星形成ゼミ
SFN #309 (18-27本目)
百瀬宗武（茨城大・理）ハイライトは以下の３本• #21: The ALMA-PILS survey: Isotopic composition of oxygen-containing complex
organic molecules toward IRAS 16293‒2422B (J. K. Jørgensen et al. A&A in press)• #24: ZOOMING IN TO MASSIVE STAR BIRTH (S. Kong et al., ApJ in press)• #26: Transport of CO in Protoplanetary Disks: Consequences of Pebble Formation,
Settling, and Radial Drift (S. Krijt et al. ApJ in press)

These enhancements are thought to be a consequence of the servations of the THz ground state transitions of H2 D (Brünken
ativetohydrogen(e.g.,
van
Dishoeck
et
al.
1995;
Ceccarelli
et
al.
stars
is
the
Class
0
+ protostar IRAS 16293–2422. This source
A&A proofs: man
et
al.
2014)
and
D
H
(Harjuetal.
2017)
towardthecoldenveexothermic
reaction2【解析】
520. TheALMA-PILS
survey:Isotopic
compositionof oxygenいくつかの遷移の積分強度図
2001)
compared tothe cosmic
D/H ratioof 1.5 2.0⇥10(e.g,., lope
has aroundlong beenrecognisedashavinglarge
abundancesof deuterIRAS
16293–2422
suggestvery
similaramountofcontaining
complexorganic
molecules
towardIRASthe16293–
基本的には，以下のローテーション++
Linsky2003;
Prodanović
etal.
2010).
In
particular,
deuterated
speciesincomparedtohigh-mass
protostellar
sources(van
H3 + HD ⌧ H2 D + H2 + E(1) both cations
this source. Due to sensitivity limitations, how2422B
ダイアグラムで分子種ごとのated isotopologues of species
such as formaldehyde (H2 CO) and ever,
Dishoeck
et
al.
1995)
and
was
also
the
first
solar-type
protothe single-dish observations typically targeted the brightJ.
K.
Jørgensen
et
al.
A&A
in
press
柱密度と温度を得る。Euの範囲がmethanol
(CH
OH)
are
found
to
be
significantly
enhanced
up
star
for
which
abundant
complexorganic
molecules
were
found
3
(where https://arxiv.org/pdf/1808.08753.pdf
E = 232 K), which followed J.by
dissociative
recomest,complex
loworganic
excitation,transitions
that in some cases may be optiK. Jørgensen et al.: Isotopic composition of oxygen-containing
molecules toward IRAS
16293–2422B
狭いもの（下パネル）はNだけ議論
tolevels
of
⇠
10%
or
above
comparedtotheregularisotopo+(Cazauxetal.
2003).
Combiningthese
twoproperties,ithasbination of H2 D with electrons leads
toanenhancedatomicvariations will more likely be statistical at this level rather thancally thick both for the main isotopologues as well as for the【内容】原始星
16293-2422Bに向けたALMA
Bandstructure.
7のラインサー
loguesin IRAS
single-dish(e.g.,
Parise
et
al.
2006)
and
the
physical
Again,
any di↵erencesat this been a natural target for deuteration studies. This is the source
D/H
ratio
that
can
be observationstransferred representing
tograinswhentheneutrallevel will only cause minor variations in the derived column den-deuterated variants. Furthermore, single-dish observations natusome ofthese sourceseven
showOtherdetectionsof systems
multiply
deuter13
sities.
For relative abundances
expressed as ratiosof column den- toward which the above mentioned multi-deuterated species,
ベイ。Oを含む有機分子およびそれらのD,
C同位体の遷移を系統的に調speciesfreeze-out(Tielens
1983).
isotopicsuch
assities between di↵erent species, error propagation translatetherally encompass the entire protostellar envelope and are thus inp(e.g., CD2 HOH
and CDOH; also
Pariseet al.ofvariations
12ated species
13
20% 3
uncertainties
into an uncertainty⇡2002
30% (= and2 ⇥ 20%) as well as some deuterated complex organics, e.g., methylCandC-containing
isotopologues
mayshow
trinsically biased toward emission on larger scales where most of
べ，柱密度・温度・同位体比を調べる。そして，これらの生成反応（特– or, e.g., 0.6 or 1.5 percentage points for D/H ratios of 2% orParise et toal.the2004)
indicating
very
degreesof
deuteration
formate(CH
OCHO;andDemyk
et al.may
2010)
anddimethyl
ether
5%,high
respectively.
But, the error couldbelower if only calibration
3located
compared
local
ISM
due
to
the
fractionation
processes
inthematerialismolecules
stillbelargelyfrozenuncertainty is an issue and other parameters such as T can beにダスト表面反応）に制約をつける。
(seealsophases
overview
in Jørgensen
etassumedal. 2016).
to be the same. This should certainly be valid for the (CH3 OCH3 ; Richard et al. 2013), were first detected. Recent obthe
coldalthoughthe variationsof
those are expected tocomparison between the C- and C-isotopologues and likelyout on dust grains due to the lower temperatures.
+servations
of
the
THz
groundstate
transitionsofH
D(BrünkenTheseenhancements
arethoughttobeaconsequenceofthesome of the deuterated species.
2【背景】
be at much smaller levels than thosealsoof
deuteriumvs.
hydrogen.
Using ALMA we haverecently completed a large unbiased
As a comparison to our method, rotation diagrams for+(Harjuetal.
2017)
towardthecoldenveexothermic
reactionCH
OD
and a-CH CHDOH are shownin Fig. 1. CH in
OD is an et al. 2014) and D2 H
Isotopeselective
photodissociationorion-molecule
reactions• Dや13Cが関わる以下の反応は，低温環境下で同位体分別を引き起こす
example of a species with a significant number of completelysurvey, the Protostellar Interferometric Line Survey (PILS), of awell-isolated lines spanning a range of energy levels. The er- lope around IRAS 16293–2422 suggest very similar amount of
the+gas through the reaction:(Jørgensen
et linesal. of2016).
rors on the derived excitation temperatures and column densitieskey frequency window around 345 GHz
+
Fig.
2.
Representativemaps
for
CH OH 89(ΔE=232K)
H3 + HD ⌧ H2 D + H2 + E
sensitivity
limitations,howare ⇡10% and 5%,
respectively (taking into account the(1)statisti- both cations in this source. Due to(⌫=347.865
GHz; more
E =143 K)sensitive
and 1716 than(⌫=344.802 GHz;
cal noise on the derived line strengths and calibration uncertain-These data are up to two orders of magnitude
E =345 K) in the upper left and right panels (a and b), respectargetedthebrightties) with the numbers otherwise in agreement with those derived ever, the single-dish observations typically
13 +
+
13
tively
and
CH
DOH
7
8
(⌫=346.43471
GHz; E =176 K) andprovideexcellent
opportuC + CO ⌧ C + CO + E(2)above. For a-CH(ΔE=35K)
CHDOH the isolated lines represent
a narrowprevious single-dish studies and thus
17
16 (⌫=355.077 GHz; E =364 K) in the lower left and right(where E = 232 K), which followed
bylevels,dissociative
in
some
cases
may
be
optirange in energy
so for this species onlyrecomthe column den- est, low excitation, transitions thatpanels(c and d), respectively.
In allpanels, theintegrations
were pernities
forsystematicstudiesofcomplexorganics
andtheirisositycanbeproperly
constrained.
The
deriveduncertainty
onthe+formed over ±0.5 km s around the systemic velocity and the contours
bination
of
H
D
with
electrons
leads
to
an
enhancedatomicas12 wellas andforcolumn density is also aboutThisvalue reflects that the fit- cally thick both for the main isotopologues
126%.
13Cの減少2H2K;
shown at 3 , 6 , 9 and(blue contours)
fromthethere upwards
以外の分子に伝播，COにおけるC/
3+への濃集→• DのH(whereE = 35Langer et al. 1984;
Furuya
et
al.
2011)
may
topologues.
In
particular,theinterferometricobservations
maketed, most isolated, transitions have S/N ratios of 8–16, i.e., thatin steps of 6 (red contours).
D/H
ratio
that
can
be
transferredtograinswhentheneutralthe statistical uncertainties on their line fluxes12
are about 6–12% deuterated variants. Furthermore, single-dish observations natu13
enhancetheCOabundanceinthegas-phase
relativetoCO.
(9% on the average). When fitting just the column
density byit possible to zoom in on the inner 30–60 AU around the cen（ただしCOは，FUVによる解離の影響も考慮する必要あり）
speciesfreeze-out(Tielens
1983).
Other
such
as
matching theisotopic
intensities, the systems
derived error goes
down withthe rally encompass the entire protostellar
envelope
and
are
thus
inmolecules
appears brighter
and where
absorption
is less of an
半ビーム分，１ビーム分
Isotopeselective
photodissociation
maydecreasetheamounttral
protostars,
i.e.,
Solar
Systemscales,wherethetemperaturessquarerootofthenumber
of
lines
–
in
this
case
six.
I.e.,
the
de12
13
issue.
• 両者の関係を分子種ごとで調べ，その起源に迫る。
C
andC-containing
isotopologues
may
also
show
variations
rived uncertainty is a factor of about 2.5 below the average statis- trinsically biased toward emission on Fig.
largerscales
where
most
of
13
12
ずれた位置でのスペクトル2comparestheintegrated
emissionaroundof CO relative to CO, but at thesame oftime
tical uncertainties
the fluxesenhancingof the individual lines.theOther sep-are high and the ices have sublimated and the complex organic
IRAS16293B for two transitions of CH OH and CH DOH
compared
to
the
local
ISM
due
to
the
fractionation
processesinaratechecksthat
theseuncertainties
arereasonable
come
from
the
materialislocatedandmolecules
may
still
be
largelyfrozen1313
13
representingdi↵erent
excitationlevels.
Thishighlights that theamount of C. Once on the grains,statisticalthe fitsenhanced
CO orlines where
C ei-molecules therefore are all present in【観測データのサマリー】
thegas-phase.
Theinitialto species with few well-isolated
emission morphologies are remarkably similar for all species
thecoldphasesalthoughthevariations
those
are
expectedtother rotationof
diagrams(Jørgensen
et al.
2016) or full -analyses
out
on
dust
grains
due
to
the
lower
temperatures.
Fig.
1.
Rotation
diagramsforwell-isolated
lines
of
CH
OD
(upperandlinestheof di↵erent
excitation levels,
what is also seen for
can
then
be
incorporated
intothecomplexmolecules.
resultspresented
thefirstdetectionsof
deuterated
isotopo(Persson
et al. 2016)organic
give similar
uncertainties.
329.1-362.9GHzをカバー，Δv=0.2km/s，ビームサイズ
0.5”(60au)
panel)andCH
CHDOH(lowerpanel).
For
theformer,both
rotation•other complex organic species identified from the PILS data
be
at
much
smallerlevels
than
those
of
deuteriumvs.
hydrogen.
Uncertainties
arising fromcontributions
to the temperature
Using
ALMA
we
have
recentlycompleteda etlarge
unbiased
12 vibrational13
and column
density can be constrained,
while thelimited(Jørgensen
et al. 2016; Coutens
et al.2016)2016; Lykke
et al. 2017).
Other mechanisms, such as segregation
andofisocyanic
acidandformamide(Coutensal.
aspartition between
functions are small CO(about 5%
or less) CO
for the Clogues
range of CH OD transitions only allow us to constrain the column denThis reenforces
theSurvey
point above (PILS),
that the bulk of
theaemission• 前例のない分解能と高感度を達成し，以下を星間空間で初検出
Isotopeselective
photodissociationorion-molecule
reactionsinisotopologuesof molecules with low
excitation temperaturessity for that species.
In bothpanels, the best fit is shownwiththe solid
survey,theProtostellar
Interferometric
Line
of
13
is dominated by relatively
compact material with relatively
in the ices due to slight di↵erences in(⇠125
theirbindingenergies
the deuterated
and represented
C-isotopologues
ofglycolaldehydeK) or ofthose for which
the vibrational (e.g.,states are well-wellline withas
our conservative
estimates on the uncertainties
byhomogeneous
physical conditions.
13C体，エタノールのD体
the dottedfrequency
lines (the best fit values
given in the upper
right corner ofthegasthroughthereaction:characterised.
For deuterated 12
species or for molecules with large key
windowaround345
GHz(Jørgensen
et al. 2016).
ケテン，アセトアルデヒド，ギ酸のD,•Smitheach panels). The dashedlines
in bothpanels indicate
the best fitsspecies
aset al. 2015) may also a↵ect theamountCmethylrelativetouncer-(Jørgensenetal.
2016).
These
all
show
correction
factors, i.p., ofethanol andformate, thisAlsomarkedin Fig.significant
2 are the continuumdeupeak and the twosuming a fixed rotation temperature of 125 K: this temperature clearly
tainty may be up to 10–25%. Generally, the assumption that the Theseo↵set positions at one
half andsensitive
one full beam (0.5
and 1 ): the
data
are
up
to
two
ordersofmagnitude
more
than
13
does
not
match
the
data
for
CH
OD
over
the
range
of
upper
energiesfor• 原始星の位置ドンピシャだとダスト連続波の光学的厚みが大きいので，
C thatis available for+ incorporation
intofactor
largermolecules.
on theby position
the with its
vibrationalof an isotopologue
of a heavier molecule is theterium enhancements – although notemission
peaks levels
close to thehinted
half-beam o↵set+
13
13
the observed lines.
same
as that of its main isotopic species will lead to an(2)underes- previous single-dish studies and thus
strength
reduced by aexcellent
factor of 2 at the full
beam o↵set position.
provideopportuCSince
+ CO
⌧
C
+
CO
+
E
timateofitscolumndensity
and
thus
lead
to
an
estimated
D/H
previous
single-dishobservations
–
but
also
indicationsofdifall of these fractionation processes are very
sensitive toThis is consistent with the emission peak being
marginally re１ビームずらした位置のスペクトルを解析（右のFigure
2,3）
ratio that is somewhat too small or a C/ C ratio somewhat too nities for systematic studies of complex
solved in that
direction. Fig. 3andcomparesspectra isotoward the twoorganics
their
半ビームではまだ連続波を背景に吸収が見えているisthoughttobeunder
relatively
homogeneous
physicalcondilarge.
Specifically,
the gas physics (density and temperature) it has therefore been ferences that may exactly reflect theiro↵setchemistries.
positions over a frequency
range where prominent (low
ex

12

3

13

3

3

18
3

up

1,17

3,6

2,8

2,15

up

2

3

2,15

5,2/3

4,5/4

3,14

up

up

1

J. K. Jørgensen et al.: Isotopic composition of oxygen-containing complex organic molecules toward IRAS 16293–2422B

18
3

2

2

3

3

3

3

12

13

00

00

Fig. 3. Spectrum of optically thick transitions of CH2 DOH at 356.95 GHz toward the half-beam (upper) and full-beam (lower) o↵set positions
from IRAS16293B. In the lower panel, synthetic spectra for CH2 DOH are overlaid: those are both calculated for the same column density (Table 1)
but with temperatures of 50 K (blue) and 300 K (red).

NH2 CHO and HNCO (Coutens et al. 2016) and CH2 OHCHO
and (CH2 OH)2 (Jørgensen et al. 2016). These divisions aremostly in agreement with a similar division into “cold” (T ex .
100 K) and “hot” (T ex & 100 K) molecules by Bisschop et al.

Formation time?

early

late

Tex

gh

13

CH2 13 CO
CHDCO

CH3 OCH313
CH3 OCH3
asym-CH2 DOCH3
sym-CH2 DOCH3

る割合がかなり一様 → exchange
2.0 ⇥ 10
As 0.042
pointed 0.021
out reactionが盛んな高温領域に速やか
previously (e.g., Garrod et al. 2008), a
Dimethyl ether
explanation
for the distinction between hot and2.4 ⇥straightforward
1017
...
...
に輸送されたため？
16
d15

1.4 ⇥cold
100.029 (1/34)may lie in the binding energies of the di↵ermolecules
4.1 ⇥ 1016
0.17
0.043
ent
16 species (also listed in Table 2). A very clear distinction is
1.2 ⇥ 10
0.050
0.025

Formation time?
early

late

CH3CH2OH

CH2CO
H2CO

CH3CHO
CH3OCH3

2–3%

4–8%

（次ページTable 3参照）

CH2(OH)CHO

氷表面での
束縛エネルギー

125 K

HCOOH
CH3OH

CH3OCHOBinding energy?

300 K

HNCO
NH2CHO

high

Tex

low

NH CHO and HNCO (Coutens et al. 2016) and CH OHCHO
and (CH OH) (Jørgensen et al. 2016). These divisions are【結果】
mostly in agreement with a similar division into “cold” (T ex .
a “hot” (Ta ex & 100 K) molecules by Bisschop et al.
Species
N100 K)
N/NandNcorr /Nmain
同等の配位がある同位体について
main
2[cm(2007)]from a survey of high-mass
hot cores and a follow-up
重みを調整した後でのMethanolstudy by. . Isokoski
et al. (2013). Also, the molecules with low exb
CH3 OH1.0 ⇥ 1019.
...
Main spices に対する存在比17temperatures
are typically those identified in the large
CH2 DOH
7.1 ⇥citation
10
0.071
0.024
CH3 OD
1.8 ⇥single-dish1017
0.018 survey
0.018 of complex organics toward IRAS 16293–
Ethanol(例えばCH
2DOHはメチル基の
2422
by
Jaber
et
al.
(2014).
Table
2
comparesthese
detections:in17
CH3 CH2 OH
2.3 ⇥ 10...
同等なHの場所が3つあるのでit seems0.059
that the hot
and cold molecules from the higha-a-CH2 DCH2 OH
2.7 ⇥general
1016
0.12
a-s-CH2 DCH2 OH
1.3 ⇥mass
1016
0.057
0.057
surveysandthe interferometric1/3する)
data agree well with a few
16
a-CH3 CHDOH
2.3 ⇥ 100.10
0.050
all the cold molecules from the interferometrica-CH3 CH2 OD[1.1 ⇥exceptions.
1016 ][0.050] Also,[0.050])13(1) Ncorr/Nmainで比較すると，
a-CH3 CH2 OH
data
15 are detected in the IRAS16293 single-dish survey again il[9.1 ⇥ 10 ][0.040 (1/25)]
a-13 CH3 CH2 OH
lustrating that that survey mayD化物
be biased
toward the colder gas on
2-3%のもの
Methyl formate
larger scales. Of the warm moleculesin the interferometric data,
D化物 4-8%のもの
CH3 OCHO
2.6 ⇥ 1017...
...
CH0.057
and NH2 CHO are seen in the single-dish3 OH に綺麗に分かれる.
CH3 OCDO
1.5 ⇥CH
1016 3 OCHO,
0.057
CH2 DOCHO
4.8 ⇥survey:
1016
0.18
0.061
those
are
all relatively abundant and thus may contribute
13
15
CH3 O CHO
[6.3 ⇥ 10 ][0.024 (1/41)]
significantly enough to be picked out in the larger beam. There
Ketenec(2)個々の分子種で異なるFunctional
16 no species detected from the single-dish observations that areare
CH2 CO4.8 ⇥ 10
...
...
)
13
groups （官能基）にDが含まれていCH2 COnot
14 detected in thec interferometric data.
7.1 ⇥ 100.015 (1/68)

es for the isotopologues of the complex organics
2 and abundances relative to the main isotopologue at the position
2
AS16293B. As discussed in the text the uncertainties on the individual column densities are about 20%, while a
一番右のカラム（Ncorr/Nmain)2
ertainties on the ratios between species are 30% from2error propagation.
Square brackets indicate tentative fits to

D/HFig. 4. Schematic representation of the results from this paper: the discussed molecules are grouped according to their D/H ratios and excitation temperatures. The species underlined can be shown to have lower
12 13
C/ C ratios by a factor 2 than typical values for the local ISM (although only tentatively for methyl formate and ethanol), while the remainder are either consistent with a standard ISM ratio or have too optically thick lines of the main isotopologue for a reliable independent
estimate.

(３)
Thave
exと氷表面での束縛エネルギー
seenbetweenspeciesthathigh excitation temperatures in
Acetaldehyde
12C/13C がISMに比べて下線があるのは17にも良い対応がある。
interferometricdata, which have binding energies
CH3 CHO1.2 ⇥IRAS16293
10
...
...
15
CH3 CDO
9.6
⇥
10
0.080
0.08
)
of
5000–7000
K(ethylene glycol as high as 10200 K), and thosefactor2以上小さかった（tentative含む）もの
13
CH3 CHO1.8 ⇥that1015 have 0.015
13
low(1/67)
excitation
temperatures,
which have binding enThe di↵erence between these (lower) sublimation tempera（右のFigure
4を参照）
CH3 CHOergiestures of 50–100 K and the higher inferred excitation temperaFormic
acide in the 2000–4000 K range. In the context of the three
12CO→
13CO̶
t-HCOOH5.6 ⇥phase
1016
...
...
原始星エンベロープが温められ放出される順序̶chemical
model
byGarrod(2013)
this
would
imply
that
tures
(100–300
K)
may
be
a
resultoftherapid
infall(andshort
高いD/H比：低温環境が
t-H13 COOH
8.3 ⇥ 1014
0.015 (1/68)c)
the bulk of the colder species simply sublimate at lower temper- distances)in thedense innermost region of 13
theCリッチになる？，
envelope aroundt-DCOOH(binding
energyの違い)で固体は一定時間続いた後に1.1 ⇥atures
1015
0.020
0.020
and vice versa for the warm species: the lower binding en- IRAS16293B. For a typical infall speed of ⇠ 1 km s 1 the timet-HCOOD
FUVの影響と関連？？？
さらなる研究が必要作られたことを反映
ergieswould
correspondtosublimation
temperatures
of
⇡
50
K
it
would
take
material
to
move
⇠50
AU
(typical of these temogue relative to that of the main species given respectively without (N/Nmain ) and with the statistical
18

16

18

A&A
manuscript
no. msTable 2. Division of molecules into “hot” and “cold” fromtheproofs:
interferometricobservationsof IRAS16293 (this study) and high-mass hot cores(Bisschop et al. 2007), an indication of whether or not the species are detected in the single-dish study of IRAS16293 (Jaber et al. 2014) and theTable energies
2. Divisionof molecules
into “hot”
and “cold”
the 2013).
interferometric observations of IRAS16293 (this study) and high-mass hot coresbindingof eachspecies (fromthe tabulation
byfromGarrod(Bisschop et al. 2007), an indication of whether or not the species are detected in the single-dish study of IRAS16293 (Jaber et al. 2014) and thebinding energies of each species (from the tabulation by Garrod 2013).
aSpecies

IRAS16293
High-mass hot cores Binding energy
Interferometric Single-dish[K]Species
IRAS16293
High-mass hot cores Binding energya
Formaldehyde
H2 CO
Cold
+
Cold / Hot
2050
Interferometric Single-dish[K]
KeteneCH2 CO
Cold
+
Cold
2200
Formaldehyde
H2 CO
Cold
+
Cold / Hot2050
Acetaldehyde
CH3 CHO
Cold
+
Cold
2775
KeteneCH2 CO
Cold
+
Cold
2200
b
Dimethyl
ether
CH
OCH
Cold
+
Cold
/
Hot
3675
3
3
Acetaldehyde
CH3 CHO
Cold
+
Cold
2775
Methylformate CH
OCHO
Hot
++
Hot
5200
Dimethyl ether
CH3 3 OCH3
Cold
Cold / Hot b
3675
Methanol
Hot
++
Hot
5530
Methyl formate CH
CH3 OHHot
Hot
5200
3 OCHO
Formamide
NH
Hot
++
Hot
5560
Methanol
CH2 CHO
Hot
Hot
5530
3 OH
Formic
acid
HCOOH
Hot
-+
Cold
5570
Formamide
NH2 CHO
Hot
Hot
5560
Ethanol
CHCOOH
Hot
-Hot
6260
2 H5 OH
Formic acid
Hot
Cold
5570
Glycolaldehyde
CH
Hot
-6680
Ethanol
C22HOHCHO
Hot
Hot
6260
5 OH
Ethyleneglycol (CHHot-102002
Glycolaldehyde
CH22OH)
OHCHO
Hot
-6680
b
Notes: a TheEthylene
listed binding
for pure
ices(Garrod2013).
Although, dimethyl
ether is classified
as hot in Bisschop et al.
glycolenergies(CH2 OH)
Hot
10200
2
a
b
(2007),
temperaturesof 80–130
K areforfound
SgrB2(N)(Belloche
et al.dimethyl2013) andG327.30.6 (Bisschop
et al. 2013),
i.e.,
Notes:The listed binding
energies
puretoward
ices (Garrod2013).
Although,ether
is classified
as hot in Bisschop
et al.
relatively
compared
to other(2007), temperatures of 80–130 K are foundtoward “cold”
SgrB2(N)(Belloche
et al. species.
2013) and G327.3 0.6 (Bisschop et al. 2013), i.e.,
relatively “cold” compared to other species.

Table 3. Inferred abundances and deuterium fractionation (from interferometric and single-dish data, respectively) for di↵erent organic molecules.
ForTablethe deuterium
thedeuterium
numbers referto the inherent
D/H ratio (i.e.,andtakinginto accountthe statisticalfor
ratiosfor thefunctionalgroups
3. Inferredfractionation,
abundances andfractionation(from interferometric
single-dishdata, respectively)di↵erent
organic
molecules.
with
H-atoms)
for the singly
deuterated
species.
As notedD/H
in thetext
thetakinguncertainties
on theabundances,e.g.,functional
D/H ratios,
from
Formultiple
the deuterium
fractionation,
the numbers
refer
to the inherent
ratio(i.e.,
into accounttherelative
statisticalratios for thegroupsthewithALMAdata H-atoms)
are about for30%;
or 1.5percentage
pointsAsfor
ratiosor 5%,
multiplethe0.6
singlydeuterated
species.
noted
in of
the2 text
the respectively.
uncertainties on the relative abundances, e.g., D/H ratios, fromthe ALMA data are about 30%; 0.6 or 1.5 percentage points for ratios of 2 or 5%, respectively.

[D/H] ratios
Species[X/CH3 OH]
Single-dishInterferometric
Model (Taquet et al. 2014)[D/H] ratios
Species[X/CH3 OH]etal.⇥2014)(⇠Single-dish1000 AU) Interferometric(⇠ 50 AU)
1.1Model⇥ 105(Taquetyr
2.0
105 yra(⇠ 7.5%1000 fAU)
(⇠ 50
1.1 ⇥
105 yr2.0 ⇥105 yrFormaldehyde
H2 CO
19%
3%AU)
2.1%
0.21%
a
Formaldehyde CH
H23CO
19%
7.5% f f,g
3%
2.1%
0.21%
MethanolOH—
1.8–5.9%2%b3.5–1.8%
0.28–0.17%f,gbb
MethanolCHOH—
1.8–5.9%2%
3.5–1.8% m 0.090%–0.12%
0.28–0.17% m
3Ethanol
CH
CH
OH
2.3%
.
.
.
5%
0.63–9.7%
3
2
bb
m
m
j
Ethanol ether
CH
CH
OH
2.3%
.
.
.
5%
0.63–9.7%
0.090%–0.12%
32
Dimethyl
CH
OCH
2.4%
3%
4%
3.7%
0.10%
3
3
j
b
Dimethyl ether CH
CH
2.4%
3%
4%
3.7%
0.10%
3 OCH3Glycolaldehyde
0.34%
...
5%c
6.5–13%0.22–0.38%
2 OHCHOcbhGlycolaldehyde
CH
OHCHO
0.34%
.
.
.
5%
6.5–13%0.22–0.38%
2
Methylformate CH
OCHO
2.6%
6%
6%
7–9%
0.25–0.22%
3hbb
Methyl formate CH
CH
2.6%
6%
6%
7–9%
0.25–0.22%
3 OCHO
Acetaldehyde
1.2%
...
8%b
9.2%l l0.068%l l
3 CHO
Acetaldehyde CH
CH
1.2%
8%
9.2%
0.068%
3 CHO
Ketene0.48%.. .. ..
2%bb
0.25%
0.015%
2 CO
Keteneacid
CH2 CO0.48%
2%
0.25% k0.015% k
FormicHCOOH
0.56%.. .. ..
2%bb
2.3–1.0%
0.58–0.66%kkFormic
acid
HCOOH
0.56%
.
.
.
2%
2.3–1.0%
0.58–0.66%dIsocyanic acid
HNCO
0.27%
...
1%d
...
...
Isocyanic acid NH
HNCO
0.27%
1%
......
. .. .. .
Formamide
0.10%.. .. ..
2%dd
2 CHO
Formamide
0.10%
... i
2% e
...
...
2 CHO
Water
HNH
O
.
.
.
0.25%
0.046%
1.2%
0.33%
2
i
e
Water
H
O
.
.
.
0.25%
0.046%
1.2%
0.33%
2
a
b
c
d
e
Notes: Persson
et al. (2018). This
paper. cJørgensen et al. (2016). dCoutens et al. (2016). e Persson et al. (2013) referring toabNotes: Persson
et al. (2018). Thisfg paper. Jørgensen et al. (2016). Coutens et al. (2016). Persson et al. (2013) referring to

Tex の高低と Binding Energy の高低がよく対応
Binding Energy を昇華温度に換算すると(50-100) K
Tex がそれより高い (100-300)Kのは，
Rapid infall のせいであろう(昇華後，infallで速やかに高温領域に到達）

化学反応モデル(Taquet et al. 2014)と観測の比較（本研究 b + 他の観測研究）“Early” model ̶1.1 105 yrの方が“Late” model ̶2.0 105 yrよりよく合う
実際には，初期条件に依存するので，
年齢の絶対値自体にはさほど意味はない24. ZOOMING IN TO MASSIVE STAR BIRTH【結果2（論文の順番とは前後するが）】S. Kong et al., ApJ in press
https://arxiv.org/pdf/1701.05953

Kong et al.
ALMA Band 6，CO(J=2-1)の高速度成分

16+00.0700【内容】IR Dark Clouds(IRDC) に付随するクランプのサーベイで見出さ
ト観測(2.3”)では分解できなかった構造を分解。原始星のほか，大質量原始星前段階 = Pre-protostellar coreの候補領域をN2D+輝線で特定。J-VLAのアンモニア観測も実施し，温度分布も推定している。

+00.0690

Galactic Latitude

れたC1-Sコアを高分解能(0.2”, Cycle 2, B6)で観測。Cycle 0のパイロッ

0.1 pc+00.0680

0.1 pc+00.0685

0.1 pc

C1-Sa+00.0675
コンパク
ト配列 +00.0670

0.00200
0.001750.001250.00100

0.00600.00075

0.00450.00050

0.00300.000250.0015広がった配列

28.3230

28.3220

28.321028.3200

C1-Sb

0.1 pc+00.0685

Galactic Latitude(d) color:Cycle 2 cont. comb. smoothed

0.00270.00240.00210.00180.0012

C1-Sa+00.0670

0.00000.1 pc0.003

0.0009
C1-S
C1-Sb

0.00060.0003

0.008
0.007
0.006
0.004

C1-Sa
C1-S
C1-Sb

0.002
0.001

+00.0665

28.3230 28.3225 28.3220 28.3215 28.3210
Galactic Longitude

0.000028.3230 28.3225 28.3220 28.3215 28.3210
Galactic Longitude

0.00200.00160.00160.00120.00120.00080.00080.00040.00040.000

0.000028.3240

28.3230

28.3220

28.321028.3200

0.0000Galactic Longitude

this is not included in these maps. C18 O(2-1) emission isnearly absent in C1-S (see also the spectra shown in Figure 6), but is rather mostly concentrated in C1-Sa andC1-Sb.
The lack of C18 O(2-1) emission in C1-S can be explained by CO depletion from the gas phase. In the C1S core and much of its clump envelope, we expect thatthe temperature is . 15 K (see, e.g., Figure 2). At suchtemperatures, CO is mostly frozen-out onto dust grains(Caselli & Ceccarelli 2012). As shown in Figure 6(3c),C1-S inner has no detected C18 O(2-1) flux (i.e., at velocities immediately around 79.4 km s 1 overlapping with
the N2 D+ (3-2) emission). We use the 3 0th-moment
C18 O(2-1) noise level (0.446 K km s 1 for C1-S inner) to calculate an upper limit of C18 O column denS innersity NCC1< 3.00 ⇥ 1014 cm 2 , assuming an ex18 O
citation temperature of 10 K and optically thin conditions. This corresponds to an abundance constraint of[C18 O]/[H]= 2.91 ⇥ 10 10 (using ⌃c,mm,tot from Table 3
and assuming 1.0 g cm 2 corresponds to NH = 4.27⇥1023
cm 2 . Assuming [12 CO/H] = 10 4 and [16 O/18 O] = 557(Wilson 1999), the above abundance constraint in C1-S
inner corresponds to a CO depletion factor of fD > 616.
Such high CO depletion factors have also been found toward the center of the lower-mass pre-stellar core L1544(Caselli et al. 1999, 2002), suggesting similarity of astrochemical properties of this source with C1-S.
C18 O(2-1) emission is observed towards the protostars
C1-Sa and C1-Sb. This is to be expected, since in the• C1-Sa とC1-Sbは立派なアウトフローあり→YSOが付随• C1-Sa：ダスト連続波質量が20-50M⦿，→ <3M⦿の原始星か。
• C1-Sbは：ミリ波フラックスがC1-Saの1/14だが，CO outflow→ 中質量前主系列星？

• 二つのYSOsの間の領域（左図 C1-Sと示されている領域）にも，か

0.00000

0.005

0.0015+00.0680

全配列+00.0675

the normal direction to the continuum elongation andthe outflow axis is approximately 30 . Also relevant isthat the origin of the outflow appears to be slightly o↵set
from the continuum peak (by one beam). The outflow is
only marginally resolved in the direction perpendicular
to the flow axis (by ⇠ 3 beams). An upper limit on thehalf opening angle of the outflow cavity is estimated to
be . 10 . One can see clumpy structures in both theblue and red lobes. The redshifted outflow appears tochange the orientation of its flow axis by a small angle,⇠ 10 , once it is about 0.1 pc away from the protostar.
The blueshifted side does not show evidence for such a
deflection, however, its overlap with the C1-Sb outflow
makes this harder to discern. The observed extent of
the outflow appears to be set by sensitivity, rather thanbeing a real, physical limit.
The outflow from C1-Sb shows a wider opening angle
at its base. The cavity walls, i.e., outflow lobe boundaries, are apparent in the extended configuration image.
The blue lobe overlaps with that from C1-Sa, but it is notclear if this involves a physical interaction or is simply a
projection e↵ect.
There appear to be some high-velocity CO(2-1) emission features in the wider region. However, some of thesefeatures may be artifacts resulting from imperfect cleaning of the image, given the strong sources of the C1-Sa
3 outand C1-Sb outflows. Or these features could beflows from other nearby protostars or other ambient highvelocity gas in the IRDC or projected along the line ofsight.

の運動量はC1-Saと同程度+00.0665(c) color:Cycle 2 continuum combined

0.0020Figure 12. CO(2-1) 0th-moment contours overlaid on the continuum images (grayscale with unit of Jy beam 1 , showing combined datafrom Figure 1). Blue contours show emission integrated from 33.8 to 72.8 km s 1 ; red contours show emission integrated from 85.8 to 124.8
km s 1 . The displayed contour levels are 5, 7.5, 10, 12.5 ... (a) Left panel: Outflow contours from extended-configuration only data (maxcontour level 25 with = 16 mJy beam 1 km s 1 ). (b) Right panel: Outflow contours from combined data (max contour level 45 with
with = 12 mJy beam 1 km s 1 ). The synthesized beams are shown in the lower left corners as filled gray ellipses.

0.00150

0.0075+00.0680
Galactic Latitude

0.01350.01200.01050.00900.0024+00.0650

3(b) color:Cycle 2 continuum extended

0.00240.0028+00.0660

Galactic Longitude(a) color:Cycle 2 continuum compact

0.1 pc+00.0670

28.3240

Zooming in to Massive Star Birth【結果1】ALMA Band 6ダスト連続波

0.0028

全配列＋
空間的に
スムージ
ング

なりの質量の物資があり，ダスト連続波でも広がって見えている。
• 明瞭なピークなし。

• ダスト連続波から，T=10Kを仮定して見積もった質量は内側領域に 25M⦿，外側領域まで含めると 60M⦿

※ 温度の不定性についてはNH 観測も参考にしつつ，後ほど詳しく議論

【結果4 ALMAのN2D+の観測結果】【結果3 J-VLAのNH3反転遷移の観測：温度の推定】

UV Taper をかけた結果（下パネルを参照）から，C1-S領域

Tk = 13-16 K. ただし，臨界密度が割と低いので，エンにはN2D+が濃集している様子が見て取れる。Starless な領

ベロープ外側の低温領域の影響があるかもしれない
Zooming in to Massive Star Birth0.80+00.0740

0.1 pc+00.0720

Galactic Latitude+00.0700+00.0680

C1-S

C1-N

0.64

0.56

0.56

0.48

0.48
C1-S

C1-N

(a) color:N2 D+

0.40

0.32

0.32

0.24

0.24

0.1 pc+00.0685+00.0680+00.0620(c) color:Tk from NH3

0.08

0.08

0.00

0.00
(d) color:zoom in to C1-S region

20+00.0740

0.1 pc+00.0675

18+00.0680

C1-N

C1-S

0.0000(c) color:N2 D uvtaper
+

18

14

0.1 pcC1-S

12+00.0660

C1-Sb

10

12
10

+00.0640+00.0680

Galactic Latitude

Galactic Latitude

C1-Sa+00.0620

28.3300

28.3280

28.3260

28.3240

Galactic Longitude28.3220

28.3200

8

6

6
28.3230

28.3225

28.3220

28.3215

C1-S

C1-Sb

(d) color:1.3 mm continuum; contour:N2 D uvtaper
+

0.028

0.1 pc0.024

0.00080.0004+00.0675

0.00000.00280.00240.020

0.00200.016

0.0016
C1-Sa

0.012

0.0012
C1-S

0.008
0.004

+00.0670

80.0012+00.0665

16

14

C1-Sa

0.0025+00.0685+00.0700

0.00240.00160.0050+00.0720

160.00280.00200.007520

0.1 pc0.1 pc0.0100+00.0670

0.16

0.02000.01750.01500.0125+00.0640

0.167(b) color:1.3 mm continuum; contour:N2 D+

0.72

0.64

0.40

+00.0660

0.80
0.1 pc0.72域であるとする見方とconsistent

Zooming in to Massive Star Birth(b) color:MIREX; contour:NH3 (2, 2)

Galactic Latitude(a) color:MIREX; contour:NH3 (1, 1)

5

C1-Sb

0.00080.0004+00.0665

28.3210Galactic Longitude28.3230

28.3225

28.3220

28.3215

28.32100.000

28.3230

28.3225

28.3220

28.3215

28.32100.0000Galactic Longitude
Galactic Longitude
e 2. (a) Zeroth moment map of NH3 (1,1) integrated from 76.9 to 81.9 km s 1 (contours, shown from 3, 4, 5 , etc., with being
km s 1 ). The integration covers the main hyperfine structure. The background image shows the MIR+NIR extinction map (inFigure 3. N2 D+ observations: (a) Combined N2 D+ (3-2) 0th-moment map. The integration is from 76.9 to 81.9 km s 1 (i.e., centered2 ) from Butler et al. (2014). The white plus signs represent the C1-N and C1-S cores from T13. The red circle in the lower-righton 79.4 km s 1 velocity measured by T13). The color scale bar has a unit of Jy beam 1 km s 1 . The synthesized beam (⇠ 0.300 ) is shown
the resolution beam of the extinction map. The black ellipse in the lower-left shows the synthesized beam of the VLA observations.
as a red filled ellipse at lower-right. (b) N2 D+ (3-2) 0th-moment contours overlaid on the 1.3 mm continuum image. The continuum image

【議論1：C1-SのStarless 領域の柱密度構造（ダスト連続波）】
Zooming in to Massive Star Birth

エンベロープ差引無9エンベロープ差引有

no envelope subtraction200【議論2：N2D+に基づくC1-S のDynamical な性質の解析】

with envelope subtraction(a)

積分したスペクトル
上が内側領域のみ
下が外側領域まで含めたもの(b)

S̄ (MJy sr 1 )150

動径輝度分布100

14速度幅の動径分布
中心付近での増加傾向（infallの兆候）は見られない

Figure 10. N2 D+ (3-2) core spectra (black) and their HFS fit
results (magenta). All spectra are in the rest frame of 79.4 km s 1 .
The spectral resolution is 0.05 km s 1 .

Kong et al.
2.0
C1-S inner

50

0.50

data
model

0.45

1.5

isothermal

Tdust = 7K
Tdust = 10K
Tdust = 13Kk⇢ = 1.5k⇢ = 0.215

6(g cm 2 )5(d)isothermalkρ＝-0.215

4

Tdust = 7K
Tdust = 10K
Tdust = 13Kk⇢ = 1.5k⇢ = 0.283

Tmb (K)(c)

動径方向で等温を仮定したときkρ＝0.283

0.5

2.0

data
model

C1-S outer

のフィット

2

0.5

0.0

のΣとΣ∝ r^{kρ}で3(km s 1 )

1.0

7

1.5

1
10

(e)

Tdust = (r/Rc )6K + 7K

Tdust (r), k⇢ = 1.5k⇢ = 1.5
Tdust (r), k⇢ = 0.414k⇢ = 0.414(g cm 2 )8(f)

Tdust = (r/Rc )6K + 7K

kρ＝0.414

6

Tmb (K)

1.0

Tdust (r), k⇢ = 1.5k⇢ = 1.5
Tdust (r), k⇢ = 0.717k⇢ = 0.717

0.0

内側ほど低温をkρ＝0.717

仮定したときのΣ4とΣ∝ r^{kρ}での
フィット

2

0

0

2000

4000
6000
R (AU)

8000

10000

2000

4000
6000
R (AU)

8000

0.5

10000

密度分布は緩やか：infall 前の状態？

igure 5. (a) 1.3 mm continuum flux density S̄1.3mm as a function of projected radius, R, for C1-S outer. The measurement is averaged
ithin concentric annuli that have widths equal to the beam size. The error bars show uncertainties due to observational noise. (b) Sames panel (a), but after subtraction of the clump envelope, as evaluated from an annulus from Rc to 2Rc . (c) Mass surface density, ⌃, asfunction of projected radius R for C1-S outer assuming isothermal conditions. The fiducial dust temperature is 10 K (black dots). Also
k

0.5

1.0

4

2

0
vLSR (km s 1 )2

4

Figure 10. N2 D+ (3-2) core spectra (black) and their HFS fit
results (magenta). All spectra are in the rest frame of 79.4 km s 1 .
The spectral resolution is 0.05 km s

1.

Table 3model k⇢ = 1.5, k = 0.25
Physicalmodelk⇢ = 0.3,properties
k = 0.20of C1-S

Core property (% error)
0.40
Angular radius, ✓c (00 )d (kpc) (20%)
0.35
Rc (0.01 pc) (20%)
VLSR,N2 D+ (km s 1 )0.30
1)N2 D+ ,obs (km s(km s 1 )0.25 N2 D+ ,nt
1)
N2 D+ (km s

C1-S inner
1.10
5.0
2.67
79.30±0.0200
0.242±0.0251
0.236±0.0257
0.302±0.0267

C1-S outer
1.85
5.0
4.48
79.30±0.0200
0.212±0.0179
0.205±0.0185
0.279±0.0231

2 ) (30%)
⌃0.20
0.490
0.445
cl,MIREX (g cm
Scl,mm (mJy)
17.5±0.577
23.8±1.04
Scl,mm /⌦ (MJy/sr)
78.7±2.60
33.1±1.44
0.15
2
1.48
⌃cl,mm (g cm )0.7980.541
0.3360.624
0.228
2
⌃0.10
) (30%)
0.492
0.491
c,MIREX (g cm
0
2000
4000
6000
8000
10000
Mc,MIREX (M ) (50%)
5.22
14.7
R (AU)
nH,c,MIREX (105 cm 3 ) (36%)
19.0
11.3
11.4±0.365
Figure 11. Sc,mm,tot
Velocity(mJy)dispersion as
a function of23.2±0.577
projected raS/⌦(MJy/sr)128±4.10104±2.60
c,mm,totdius, R, for
C1-S outer. The observational measurement is av2)⌃
(g cm annuli
1.963.93
eraged withinconcentric
at a 2.41
step4.83
of beam size.
Withinc,mm,tot
1.43
1.16
53.5
123
each annulus,
observed§3.2.3.
Mthe(M ) N2 D+ is derived
25.511.6following
58.8
c,mm,tot
26.8 The
53
190
nH,c,mm,tot(10 cm) projection
93.051.6
45.192.1
black model
curve shows
the 2D(mass-weighted
25.0sum in
2
4.03
3.60
k
1.610.628
1.630.826profile
quadrature) ⌃ofc,mm(r)(g cm/ r ) (k = 0.25)
with the density
43.7
112(M )following the17.1⇢(r) / r k⇢ M
(kc,mmfiducial
model.
⇢ = 1.5),
4.97 MT0348.8
19.0 The
6
3
15.8
8.39
2
nH,c,mm (10based
cm on
) a
6.222.24
profile is normalized
minimization
to 3.73
the1.77
observa-tion sothatsuperscripts
the at coresurface(9250 AU)andis subscripts
s 1.
s = 0.306 km
The(lowtemperature)(high
The bluemodel curveshowsthethevariations
model witha shallower
temperature)indicate
resultingfrom density
dust
0.3
profile
⇢(r)
/
r
and
the
best
fit
k
=
0.201.
In
this
case,
temperature uncertainties(7 to 13 K for core; 10 to 20 K for1
0.245 km s .
s = clump).

along with
theirC1-Sclumpinnerenvelope
densities,
dispersionsof theand mass
outersurface
core structures,

we are able to compare these to predictions of the Turbulent Core Model of MT03. Our general methodologicalapproach follows that of T13. The mass-weighted average velocity dispersion of a virialized core, includingpressure equilibrium with its surroundings, is given, in
the fiducial case by (MT03; T13):✓◆ 3/8 ✓
◆1/4 ✓
◆1/4
Mc
⌃cl
B
km s
c,vir ! 1.09
2.8
60M
1 g cm 2

s.
bst
pal
ss
iof
ald
s,
ve
aat
ge
-S
ng
ce
le.
6)
a
rof

te
oeic
rld
er
ve
an
nd

Table 4
Dynamical properties of C1-S

【N2D+に基づくC1-S のDynamical な性質の解析（続き）：ビリアル解析】

Core property
Rc (0.01 pc)
1)
(km
s
+
N2 D
⌃cl,mm (g cm 2 )Mc,mm,tot (M )Mc,mm (M )1)c,vir,mm,tot (km s1)c,vir,mm (km s
N2 D+ / c,vir,mm,tot
N2 D+ / c,vir,mm
nH,c,mm,tot (105 cm 3 )nH,c,mm (105 cm 3 )tc,↵,tot (105 yr)atc,↵ (105 yr)a2b↵c,tot ⌘ 5 N
R
/(GM
)
c
c,mm,tot+
D

C1-S inner
2.67
0.302±0.0267
0.7981.48
0.541
25.553.5
11.6
17.143.7
4.97
0.8321.03
0.606
0.7520.973
0.500
0.3630.499
0.293
0.4020.604
0.311
93.0190
51.6
62.2158
22.4
0.1430.192
0.100
0.1750.291
0.110
0.1100.245
0.0457

C1-S outer
4.48
0.279±0.0231
0.3360.624
0.228
58.812326.8
48.811219.0
0.8261.02
0.602
0.7880.994
0.557
0.3370.463
0.272
0.3540.500
0.280
45.192.1
25.0
37.383.9
17.7
0.2060.276
0.144
0.2260.328
0.151
0.06830.152
0.0286

0.1650.568
0.05540.08240.213
0.0315

Bc,tot (mG) (mA = 1)
Bc (mG) (mA = 1)

0.8651.24
0.632
0.7081.13
0.418
73.7
41.717.9
31.963.3
10.7
0.1930.301
0.144
0.2210.399
0.156
6.98
4.492.47
3.195.54
1.27
3.245.42
1.95
4.19
2.170.873

0.5550.798
0.406
0.5060.761
0.343
89.8
50.821.8
44.883.2
17.8
0.1740.270
0.130
0.1860.302
0.135
4.95
3.191.77
2.724.43
1.36
2.644.42
1.59
2.193.90
1.15↵c ⌘ 5

2

2
b
R
/(GM
)
c
c,mm
N2 D +

B,vir,tot
B,vir

mA,vir,tot
mA,virBc,vir,tot (mG)
Bc,vir (mG)Bc,crit,tot (mG)Bc,crit (mG)

The superscripts (low temperature) and subscripts (high temperature) indicate the variations resulting from dust temperature
uncertainties (7 to 13 K for core; 10 to 20 K for clump).
aCore free-fall time, tc,↵ = [3⇡/(32G⇢c )]1/2 = 1.38 ⇥
105 (nH,c,mm /105 cm 3 ) 1/2 yr.
bVirial parameter (Bertoldi & McKee 1992).

tot がついているのは，envelope のsubtraction なし
tot がついていないのは envelope のsubtraction あり← ダストで求めた質量を持つビリアル平衡球で期待される速度幅← N2D+で測定された速度幅：上より小さい← コアを支えるのに十分な速度分散がない
可能性
1. 収縮直前のコアをたまたま見ている←もっともらしくない（密度で決まるFree-fall time scaleは結構短いので）。
2. 磁場で支えている：sub-Alfvenic turbulence(mA ≈ 0.2)で,B=2-3 mGで支えられる。
Crutcher et al. (2010) で提示されているnH vs. |Bz| 関係によれば，このクラウドの密度(~106 cc-1) でこの磁場強度はもっともらしい。
いずれ，ここから大質量星が形成されるのではないか。

sequestration
of
ices
in
the
midplane(Meijerink
et
al.
M
For
CO,
this
story
of
depletionabove
thesurfacesnowdiskby choosing a total disk mass
particular importance because CO emission is commonly
whichisnormalized
2.1.
Disk
.
(2)
⌃
=
(2
p)
c
of
CO
in
di↵erent
environments(Sect.
2.3).
Finally,inEven before pebblesline
start
drifting
however,thefor2and2009;potential
enhancement
the inner
is of Du et al. 2017).
Du
et al.&2015;
et diskal. 2016;
2⇡rc
used as a tracer for bulk disk mass
(e.g.,
Williams
BestinKama
Mdiskcoagulatemationof Protoplanetarythese large, particular
settledDisks:dust
particles
can changeSect.
3.5.1,
weoutline
how
small
dust
grainsimportancebecauseCOemissioniscommonly
26. TransportofCO
inConsequences. on a disk around(2)p) focus【モデルの概要】ガス円盤の物理構造
Modelsstudying
vertical mixing
find that this e↵ect can ⌃c = (2 We
2014; Ansdell et al. 2016; Miotello
et al.
2016, 2017;2
For top=
1, sucha profile contains 10%, 63%, 2⇡r86%,
andusedofasanda tracerfor bulk
disk mass& Bestthe Formation,
vertical distribution
gas-phasevolatiles
via (e.g.,the Williams
form
pebbles.
cof Pebble
Settling,
RadialDrift
gas surface density profile(L
decreasethegas-phase
H
O
and
CO
abundancesinthe
Molyarova et al. 2017). 2014;
Hence,Ansdell
if theetCO
abundance
2009)2
2016; Miotello
2016,
2017;
95%
of thedisk’s mass
0.1,a profile
1, 2, and
3rc , respecsequestration
ofal.icesin themidplaneal.
(Meijerink
et al.et al.
S. Krijt et(ApJ,inpress)
For p within= 1, suchcontains
10%, 63%, 86%, andHartmann
et al. 1998) @C
2.1.temperature,Disk
structureishttps://arxiv.org/pdf/1808.01840.pdf
significantly
depleted inMolyarova
the regionof 2017).
the disk
thatif bywarm
molecularlayer
anywhere
betweenafactorofaetal.
Hence,
theCOabundance2
tively.
For
themidplane
weassume2009; Du et al. 2015; Kama et al. 2016; Du et al. 2017).
95% of the disk’s mass within 0.1, 1, 2, and 3rc , respeci
dominates the emission, thisapproachcould
bein2underis significantly
depletedtheregionofmagnitude,
the disk
that
few
to
almostordersofdepending
on
the
the
assume✓ ◆ @t
Wefocus
on tively.
a diskFor
arounda 1Mstar, with aweradial⇣ rmidplane⌘
Models studying vertical mixing find that this e↵ect canp
1/2 temperature,r
dominates
theemission,
thisapproach
could be underestimatingmagnitude
the true disk
mass.
For
the
handful
of
disks
of
which
depends
ontheunderlying
pebbleportofgas-phasemoleculesandsolids(Sect.
2.2),
and
⇣
⌘
T
(r)
=
T
,
(3)
gas surface
profile1974;
involvedinandthe detailsof thedensity
pebbleformamid
0 (Lynden-Bell & rPringle
1/2
decrease the gas-phaseestimating
H2 O timescales
andtheCOtrueabundances
the
⌃
(r)
= ⌃c
e
g
au
disk
mass.
For
the
handfulofdisks
for which flux
independent
mass estimates can be made us(r) =freeze-out
T0, desorption
(3)
and
ice
content.
conditions
and rates atTmid
which
and
r
c
Hartmann
et
al.
1998)
warm
molecularlayer
byanywhere
betweenafactorofation
process
(Xu
et
al.
2017;
Krijt
et
al.
2016).
au【内容】円盤内でのCO分布のに対して，Pebble
for whichindependent
mass estimates
be madeusing HD, it appears
as thoughCO の形成，沈殿，動径移動がisindeeddepletedby a thecan
with
T
=
130
verticaldensity
structureis2.3).
thenFinally, inof
COK.inThedi↵erent
environments(Sect.
Even
beforepebblesstartdrifting
however,for0()
few to almost 2 ordersingofHD,magnitude,
dependingonthe◆130p K. The vertical✓ ◆2density
itFor
appears
asthisthoughCO isindeeddepletedby a the surface
CO,
story
of
depletionabove
snowwith ✓T0 =structure is thenp
where
及ぼす影響をシミュレーションで調べた。Pebbleの形成なしだと，COの存
whichisnormalizedbychoofactor
of
a
few
to
up
to
two
ordersofmagnitude(Favreparametrizedasfollowsrr
mationoftheselarge,
settleddust
particlescanchangeSect.
3.5.1,
weoutline
how
small
dust
grainscoagulatetimescales involved andthedetailsofthepebbleformafactor of
a few
to up
to two ordersof magnitude (Favre
asexp
follows⌃g (r)=parametrized⌃cdisk is of
,
(1)
line
and
potential
enhancement
in
the
inner
Di is
⇢
et
al.
2013;
McClure
et
al.
2016;
Schwarzetal.
2016).
Inthevertical
distributionofgas-phasevolatiles
via
the
to
form
pebbles.
⇣⌘rr⇢在比に大きな変化はおきない。Pebbleが形成されて赤道面に沈殿すると，固cc2
al. 2013;
McClureal. 2016; Schwarz et al. 2016). In
tion process (Xu et al.et2017;
Krijt
et al. et2016).
⇣ z ⌘2
⌃
(r)
1
z
g
tion.
⌃
(r)
1
particularimportancebecauseCOemissioniscommonly
g
p
⇢
(r,
z)
=
exp
(4)
addition,
CO
is
the
only
molecule
for
which
the
snowsequestrationoficesin themidplane(Meijerink
etal. the snowg
⌃
=
(2
p
⇢
(r,
z)
=
exp
(4)
addition,
CO
is
the
only
molecule
for
which
c
g
For
CO,
this
story
of
depletionabove
thesurfacesnow相に取り込まれたCOが円盤上層から抜けるため，ガス円盤全体（上層部）
2
H
(C
=
2⇡H
2.1.
Disk
structure
2
H
v
2⇡H
which
is
normalizedbychoosing
a
total
disk
mass
used
asal.
a 2013)tracerforforbulk
disk
massand(e.g.,
Williams & Bestline line
has been(directly)
observed
(Qi
et
and
2009;
Du
et
al.
2015;
Kama
et
al.
2016;
Du
et
al.
2017).
line
has
been
(directly)
observed
(Qi
et
al.
2013)
for
and
potential
enhancement
in
the
inner
disk
is
of
presenでCOがdeplete。実際はpebble
が中心へと落下するはずで，その場合は，
which
we
can
verticallyandradially
resolveabundances
where
the
scale-heightiscasgiven
bystar,Hsound= ourcs /⌦,
theradialsoundWe
focus
on
a
disk
around
1M
with
a
which
we
can
verticallyandradially
resolveabundances
where
the
scale-height
is
given
by
H
=
/⌦,
the
2014;
Ansdell
et
al.
2016;
Miotello
et
al.
2016,
2017;
Modelsstudying
verticalmixing
find
that
this
e↵ect
can
Figure1.
Bulkgas
densityandtemperature
for
stanM
p
disk
p
For
p
=
1,
such
a
profileconparticular importance because CO emission is commonly
solve
E
.
(2)
⌃
=
(2
p)
cc(seeusing aMolyarova
varietyof COisotopologues(Schwarz
et al.csif
2016;
speed
kand
(r)/µm, andµ=Pringle
2.3 isde-the
mean
dard
disk
model
Sec.
2.1).
The
black
contours =H
B TmidHis
gas
surfacedensity
profile(Lynden-Bell
&
1974;
2
using
a
varietyofisotopologues(Schwarz
et
al.
2016;
speed
=
k
T
(r)/µm
,
µ
=
2.3
the
mean
CO snowline 内側でCOが再び気相に戻ってCO存在比が増えるはず。
decreasethegas-phaseHO
andabundances
in
the
B
mid
et
al.
2017).
Hence,
theCOabundance
2 (e.g., Williams & Best2⇡rc 95% of the disk’s mass vwithi
used as a tracer for bulk
disk
mass
r =
notes
the
⌧
=
1
surface(Eq.
7,anddashed
lines
show
Zhang
et
al.
2017;
Dutrey
et
al.
2017;
Pinte
et
al.
2018;
molecular
weight.
Temperatures
at
the
disk
surfaceare
UVet al. 1998)
Hartmann
Zhang
et
al.
2017;
Dutrey
et
al.
2017;
Pinte
et
al.
2018;
molecular
weight.
Temperatures
at
the
disk
surfacearewarm
molecularlayer
byanywhere
betweenafactorofadi↵usioissignificantly
depletedintheregion
of
the
disk
that
2014; Ansdell et al. 2016;
et al. 2016, 2017;
z/H
=
{1,
2,
3,
4}.
Huang Miotello
et al. 2018).
elevatedas they
are directly
exposedtoradi- temtively.
Forthewarming
midplane
For pas= they1, suchadirectly
profilecontains
10%,
63%,
86%,
and
(
)
Huang
et
al.
2018).
elevatedareexposedtowarming
radifew toetalmost
2 ordersofmagnitude,
depending
on
the
✓
◆
✓
◆
the Sc
実際の観測データでは，COの内側領域でのenhance
は見えてないので，
p2 we
p adopt a verMolyarova
al. 2017).
Hence,
iftheCOabundance
dominates
theemission,
thisapproachcouldbeunderThe aim of this paper is to construct a self-consistent
ation(Chiang&
Goldreich1997);
here
95%
of
the
disk’smass
within
0.1,
1,
2,
and
3r
,
respecrr
cThe
aimtimescalesof this paper
ismodeltoinconstructa self-consistent
ation(Chiang & ⌃Goldreich1997); sturcture
here
we adopt
abasedver- on, Rosenfeld
Sc = 1
involved
andtheregion
detailsofthe
thepebbleforma(r)
=
⌃
exp
(1)
that
describes
howtheformationandsubsequenttical
temperature
that
is
g
c
is
significantly
depleted
the
of
disk
that
柱密度分布
estimating the true disk mass.
ForThethehandfulof disks
analyticalsolutionin Eq. 7 is only
valid
when the• Pebble の落下を妨げる機構？
tively.
For
themidplanetemperature,
weassume
r
r
T
(r)
=
T
c
c
mid
0
disk
w
model
that
describes
howtheformationandsubsequenttical
temperature
sturcture
that
is
based
on
Rosenfeld
tion
process
(Xu
et
al.
2017;
Krijt
et
al.
2016).
verticalsettling
andradialdriftofpebblesaltersCOetal.
(2013);
Dutreyetal.
(2017):
above
z
=
z
H,
the
q
dominates the emission, thisfor
approach
could
be under-mass estimates
dust-to-gas
ratio
isconstantwithheight.
Duringourwhichindependent
can
be
made
us⇣ rabove⌘ 1/2• 固相に取り込まれたCOが別のより難揮発性化学種に変わっている？
Forverticalsettling
andradialdriftofpebblesaltersCOetal.
(2013);
Dutreyetal.
(2017):
z
=
z
H,
the
For
CO,
this
story
of
depletionabove
thesurfacesnowabundancesindi↵erent
regions
of
the
disk;
both
inteatmospherictemperatureisparametrizedasqestimating the true disk mass. For the handful of disks
simulations,however,
the
small
grain
abundance
will
which
is
normalizedbychoosing
a
total
disk
mass
T
(r)
=
T
,
(3)
温度（中心面）
mid is by
0HD,disk;
itintheappears
assnowline,
thoughCOindeeddepleteda au with
T0 = 130 K. The vertic
radialriorenhancement
andingexteriortomidplaneaswellisasinabundancesindi↵erent
regionsoftheboth
inteatmospherictemperatureparametrizedas
可能性を考慮する必要がある。
line
andpotential
the
inner
disk
is
of
vary in time and space andTweevaluatethefor which independent mass estimates can be made us= 3Tmid(r),integral in(5)
atm (r) M
Armitathewarmersurfacelayers
of
the
outer
disk.
To
that
end,
factorofaas
few
toasupto two orders Eq.
of magnitude(Favreparametrizedasfollows
diskrior ing
andHD,
exteriortothemidplanesnowline,well
inparticularimportancebecauseCOemissioniscommonly
7 130
numerically.
it appears as thoughCOisindeeddepleted
by
a
with
T
=
K.
The
verticaldensityisthen (2).
⌃3T= (2p) structure
0
c mid
Tand
(r)smaller
=
(r),
(5)
上空では
2
atmfor
we
focus
on
a
single,invariantdisk
profile(Sect.
2)andz exclusively2⇡ron
the warmer
surfacelayers
of
the
outer
disk.
To
that
end,
et
al.
2013;
McClure
et
al.
2016;
Schwarzetal.
2016).
In
used
asa
tracer
for
bulk
disk
mass
(e.g.,
Williams
&
Best
In
this
paper,
wefocus
c a disk model（この論文のモデルでは，CO凍結・昇華やダストの成長とそれに伴うガス
factor of a few to up totwoordersofmagnitude(Favreparametrizedasfollows⌃2g (r)model the vertical and radial transport of dust, pebbles,✓◆
we focusa single,
invariantdisk
profile(Sect.
2)al.
and
with
r
=
100
au,
p
=
1,
and
M
=
0.05
M
.
Figure1
2014;
Ansdelletal. 2016;
2016;
Miotello
et
2016,
2017;
p
⇢
(r,
z)
=and
e
addition,
CO
is
the
only
molecule
for
which
the
snowc
d
⇡z
and
for
smallerz⇢g
et al. on
2013;
McClureetices,al.
Schwarzetal.
2016).
In
円盤中での移動は詳細に解いているが，化学反応は解いていない）
For
p
=
1,
such
a
profilecontains
10%,
63%,
86%,
⇣
⌘
and gas-phase CO while pebbles are continuously
中間では
2 (r)) sin
T (r,density
z) =
T(r)
(r)+(T
Tmid,
mid
atm1(r)
⌃
z
2⇡H
g
shows
the
gas
(Eq.
4)
and
temperature
structuremodel
theverticalandradialtransportofdust,
pebbles, 0.1,✓ 1, 2, and◆ 2 3r(4)Molyarova
et al.
2017).
Hence,
if theCO(Sect.
abundance
2z
qH
line
has
(directly)
observed(Qi95%et ⇢al.
2013)
andmass
forexpz) disk’s=paddition,
CO is theonlymolecule
forbeenwhich
thesnowforming
overMyr
timescales
3).
By comparingofthewithin,respecg (r,
c
⇡z
for
these
parameters.
Dustisinitiallypresent
at
a
dust2
H
(6)
2⇡H
ices,line
andhasgas-phaseCO
whilepebblesarecontinuouslyissignificantly
depletedintheregion
of
the
disk
that
T
(r,
z)
=
T
(r)+(T
(r)
T
(r))
sin
,
modelsofincreasing
complexity(Sect.
4)
andexploring
mid
atm
mid
been (directly) observed(Qiwe
et al.
and forand radiallytively.
which
can2013)
verticallyresolveabundancesForthemidplanetemperature,
weassumewhere
thescale-height
is
give
in
whi
2z
H
p
zq
=
3,
δ=2
to-gasratio
of
1/100,
withallgrains
being
s
=
0.1
µm
where
we
will
use
z
=
3
and
=
2.
We
also
calculateq•q
forming
Myrverticallytimescales(Sect.
3).approach
Byseveralcomparing
dominates
the emission,
this
could
be undertheanddependenceonparameters
relatedto peb3
whichover
we canradially
resolveabundances
where
the
scale-height
is
given
by
H
=
c
/⌦,
the
sound3⇣⌘susing a variety
of isotopologues(Schwarz
et
al.
2016;
speed
c
=
k
T
(r)/µm
10
r
1/2
(6)
sg/cm
B
mid
p
the
cumulative
UV
vertical
opticaldepth.
Assuming
in
size
with
a
material
density
of
⇢
=
2
.
For
•
r
ble formation/evolution(Sect.
5), weofattempt
to build amodelsofestimatingcomplexity
4)For
andtheexploringthetruedisk(Sect.
mass.
handfuldisks speed
usingaincreasing
variety of
isotopologues(Schwarz
et
al.
2016;
cwill
kthat
Tmid
(r)/µm
,
and
2.3
is
the
mean
4T0 µ
2 =
T
(r)
=
,
(3)
the ga
s =
B et
H
mid
dust
is
the
primary
absorberofradiations,
with
these
numbers,

⇡
8
⇥
10
cm
/g.
The
coloredconZhang
et
al.
2017;
Dutrey
et
al.
2017;
Pinte
al.
2018;
where
we
use
z
=
3
and
=
2.
We
also
calculatemolecular
weight.
Temperatuv
qcoherent
story estimatesofrelated
how pebble
migrationa↵ectsCO abun- depthも計算し，CO desorptionの見積もりに役立てる
au
UVのoptical
the Zhangdependenceonseveralparameterstopebforwhich
independent
mass
can
be
made
uset al. 2017; Dutrey et al. 2017; Pinte et al. 2018; the molecularweight.
Temperatures
at
the
disk
surfacearevelocitanopacity
of

=
3/(4s
⇢
),
where
s
are
UV
•
•
•
tours
show
varioustemperatures
as
well
as
the
⌧
=and
1are⇢• directly
cumulative
UV
vertical
opticaldepth.
Assuming
UV
dances Huangon a disk-wide
The results are discussed
et al. scale.
2018).
elevated as they

モデルのフレームワーク
COと小さなダストはグリッド点上で進化を追い，
ペブルはラグラジアン的に取り扱うモデル内でのペブルの成長のポンチ絵

5

Photo-desorption
Sublimation
Freeze-out

t).

2)

m-

3)

ng
es
by
a

=
th
is
ld
V
),

Sublimation(a)質量 vs. 空隙率進化
Coagulation

Figure 2. Conceptual framework of the hybrid model described in Sect. 3. The abundances of CO vapor (Cv ), small
dust grains (Cd ), and the ice-frozen-out-on-small-dust-grains(Cice ) are all followed on a logarithmic 2-dimensional grid
(Sect. 3.1). Pebbles, on the other hand, are described using Lagrangian tracer particles, whose motions through thedisk are simulated using a Monte Carlo approach (Sect. 3.5).
Arrows represent various interactions between di↵erent components, all of which are described in more detail in the text.

(b)ペブルのSt数分布(c)ペブル形成のタイムスケール

Figure 3. Cartoon of how pebble formation proceeds in our model (see Section 3.5.1). Initially, monomers of size s• growinto dust aggregates with a fractal dimension of ⇡2 (stage I). When the kinetic energy in collisions becomes large enough,restructuring occurs and aggregates grow at a constant internal density (stage II). After the bouncing threshold velocity is
7
exceeded, bouncing collisions efficiently compress the aggregates (stage III). The term ‘dust’ refers to all solids in stage I, andwe refer to the end-products of stage III as ‘pebbles’: the end-products of local dust coagulation.

(Sect. 3.1 and 3.3). The growing population of pebbles, on the other hand, is represented by Lagrangian
tracer particles (or, representative particles) and we use
a random-walk-like approach (with added settling andradial drift) to track their movement (Sect. 3.6). Given
some initial conditions (detailed in Sect. 3.2), we calculate forward in time using a combination of implicit andexplicit techniques to account for the interactions shownin Fig. 2.
3.1. Grid & boundary conditions

port in the disk is limited to z/H  4 by setting the diffusivities and initial concentrations to 0 above z/H = 4(similar to Ciesla 2009).
3.2. Initial conditions
At t = 0, we start out with well-mixed dust and COvapor: Cd (r, z) = Cd0 = 10 2 and Cv (r, z) = Cv0 = 10 3(corresponding to roughly 10 4 CO molecules per H2molecule). Then, we allow the CO to freeze-out until
an equilibrium is reached in every grid cell. No pebbles
exist at the start of the calculations.

Similar to Ciesla (2009), we set up a logarithmic grid
Figure 4. with
Illustration
formationframework
model of Sect. 2.1 and using s• = 0.1 µm,
ri+1 /ri of= the
1.05pebble
and zi+1/zi = 1.1,
with r0 =(Sect.
10 au3.5) for the disk3.3.
Transport of vapor, dust, and ice
fw = 0.5, andc = 0.4. (a): The three stages of local dust growth (see Sect. 3.5.1) and their end-products at three di↵erent
and z0 = 0.25 au (at every radius). The number of
Following(b):Ciesla(2009),
the transport
vapor,
ice,
midplane locations. Numbers correspond to log10 (s/cm) and log10 (St) (in brackets).
Stokesnumbersof pebbles of(solidblack
cells in the radial direction is chosen such that the outeranddustcurves
is calculated
explicitfragmentation
integration of
curve) formed in the midplane as a function of heliocentric distance. The
redsmalldasheddepict a byconstant
radius corresponds to approximately 3rc = 300 au. EvEq. 8curvefor eachcomponent
usingStokes
the method
threshold vf (Birnstiel et al. 2012, Eq. 3) of 1 and 5 m/s, and the blue dashedshows
the maximum
number ofin finitetheery grid cell can be thought of as a ring with volume2
withTimescalea time stepa fraction
fc ofdrift-limited scenario (Birnstiel et al. 2012, Eq. 17) for a dust-to-gas ratiodi↵erencesof 10 . (c):for chosen
pebble asformationin theV=2⇡rrz,
covering
an
area
A
=
2⇡r
r
when
1
midplane from Eq. 25 (green curve) comparedto the vertical mixing timescale⌧z ⇠(vertical)(↵⌦)
andthe viscoustimescalet⌫ forthe smallest
di↵usiontimescaleacross any
grid
3
3 projected on to the midplane .
Theboundarycon↵ = 10 .
cell:⇢ditions are reflective at the midplane (@C/@z = 0)
( zi ) 2
at the ,end of stage
decrease withparticle
massboundaryand collisionve-domain more extreme porositiest = faremin(17)
c ⇥reached
and increasingat the innerand outerof the10【結果】シミュレーションの時間発展

初期 CO
存在度

（右）Pebbleの形成なしだと，COの存在比に大きな変化はおきない。

0.1Myr
変化分（中央）Pebbleが形成されて赤道面に沈殿すると，固相に取り込まれたCOが円盤上層から抜けるため，ガス円盤全体（上層部）でCOがdeplete。
（左）pebble が中心へと落下すると，
CO snowline 内側でCOが再び気相に戻ってCO存在比が増えるはず。

実際の観測では，内側でのCO plumeは0.3Myr
変化分

1Myr
変化分

1Myr CO存在度

見えてないので，さらに別の要素も考える必要あり（COの別の化学種への変化，落下を妨げる円盤不均一や微惑星からの影響）Figure 5. Time evolution (top-to-bottom) of the gas-phase CO number density in models M0a, M0b, and M1 (left-to-right).
Top and bottom rows show number densities while the middle three rows show number density relative to the initial conditions
at t = 0, with blue representing an enhancement and red a depletion in gas-phase CO density. Contours for ⌧UV = 1 andT = 22 K are also drawn and the faint dashed lines indicate z/H = {1, 2, 3, 4}.

1818

Constraining the gap size in the disk around HD 100546 in the mid-infrared
Narges Jamialahmadi1 , Thorsten Ratzka2 , Olja Panić3 , Hassan Fathivavsari1 , Roy van Boekel4 , Sebastien Flement5 , Thomas Henning4 , Walter Jaﬀe6 , and Gijs D. Mulders71

School of Astronomy, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5746, Tehran, Iran; 2Institute for Physics / IGAM, NAWI Graz, Karl-Franzens-Universität, Universitätsplatz 5/II, 8010 Graz, Austria; 3
School of Physics and Astronomy, University of Leeds, Woodhouse Lance, LS29JT Leeds, United Kingdom; 4 Max
Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany; 5 Laboratoire J.-L. Lagrange, UMR
7293, University of Nice Sophia-Antipolis, CNRS, Observatoire de la Cote DAzur, Boulevard de lObservatoire - CS
34229 - F 06304 NICE Cedex 4, France; 6 Sterrewacht Leiden, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands; 7
Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721, USA Earths in Other Solar Systems
Team , NASA Nexus for Exoplanet System ScienceE-mail contact: nari.jami at gmail.com
We refine the gap size measurements of the disk surrounding the Herbig Ae star HD 100546 in the N band. Our new
mid-infrared interferometric (MIDI) data have been taken with the UT baselines and span the full range of orientations.
The correlated fluxes show a wavy pattern in which the minima separation links to a geometrical structure in the
disk. We fit each correlated flux measurement with a spline function, deriving the corresponding spatial scale, whileassuming that the pattern arises interferometrically due to the bright emission from the inner disk and the opposing
sides of the wall of the outer disk. We then fit an ellipse to the derived separations at their corresponding position
angles, thereby using the observations to constrain the disk inclination to i = 47 ± 1 degree and the disk position
angle to P A = 135.0 ± 2.5 degree East of North, both of which are consistent with the estimated values in previous
studies. We also derive the radius of the ellipse to 15.7±0.8 au. To confirm that the minima separations translate
to a geometrical structure in the disk, we model the disk of HD 100546 using a semi-analytical approach taking into
account the temperature and optical depth gradients. Using this model, we simultaneously reproduce the level andthe minima of the correlated fluxes and constrain the gap size of the disk for each observation. The values obtained
for the projected gap size in diﬀerent orientations are consistent with the separation found by the geometrical model.

Accepted by ApJ
http://arxiv.org/pdf/1808.05052

13

for the projected gap size in diﬀerent orientations are consistent with the separation found by the geometrical model.

19 Accepted by ApJ
http://arxiv.org/pdf/1808.05052

19

The dependence of stellar properties on initial cloud density
Michael O. Jones1 and Matthew. R. Bate1
1

School of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, United Kingdom

E-mail contact: mbate at astro.ex.ac.uk
We investigate the dependence of stellar properties on the initial mean density of the molecular cloud in which stellar
clusters form using radiation hydrodynamical simulations that resolve the opacity limit for fragmentation. We havesimulated the formation of three star clusters from the gravitational collapse of molecular clouds whose densities varyby a factor of a hundred. As with previous calculations including radiative feedback, we find that the dependenceof the characteristic stellar mass, Mc , on the initial mean density of the cloud, ρ, is weaker than the dependence ofthe thermal Jeans mass. However, unlike previous calculations, which found no statistically significant variation in
the median mass with density, we find a weak dependence approximately of the form Mc ∝ ρ−1/5 . The distributionsof properties of multiple systems do not vary significantly between the calculations. We compare our results to theresult of observational surveys of star-forming regions, and suggest that the similarities between the properties of ourlowest density calculation and the nearby Taurus-Auriga region indicate that the apparent excess of solar-type stars
observed may be due to the region’s low density.
Accepted by MNRAS
https://arxiv.org/pdf/1806.01033

20

Sink particle radiative feedback in smoothed particle hydrodynamics models of starformationobserved may be due to the region’s low density.
Accepted by MNRAS

20 https://arxiv.org/pdf/1806.01033

20

Sink particle radiative feedback in smoothed particle hydrodynamics models of starformation
Michael O. Jones1 and Matthew R. Bate1
1

School of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, United Kingdom

E-mail contact: mbate at astro.ex.ac.uk
We present a new method for including radiative feedback from sink particles in smoothed particle hydrodynamics
simulations of low-mass star formation, and investigate its eﬀects on the formation of small stellar groups. We findthat including radiative feedback from sink particles suppresses fragmentation even further than calculations that
only include radiative transfer within the gas. This reduces the star-formation rate following the formation of theinitial protostars, leading to fewer objects being produced and a lower total stellar mass. The luminosities of sinkparticles vary due to changes in the accretion rate driven by the dynamics of the cluster gas, leading to diﬀerent
luminosities for protostars of similar mass. Including feedback from sinks also raises the median stellar mass. The
median masses of the groups are higher than typically observed values. This may be due to the lack of dynamicalinteractions and ejections in small groups of protostars compared to those that occur in richer groups. We also find thatthe temperature distributions in our calculations are in qualitative agreement with recent observations of protostellar
heating in Galactic star-forming regions.
Accepted by MNRAS
https://arxiv.org/pdf/1807.09849

21

The ALMA-PILS survey: Isotopic composition of oxygen-containing complex organic
molecules toward IRAS 16293–2422B

https://arxiv.org/pdf/1808.08753.pdf

22

22

Distortion of Magnetic Fields in a Starless Core IV: Magnetic Field Scaling on Density
and Mass-to-flux Ratio Distribution in FeSt 1-457
Ryo Kandori1 , Kohji Tomisaka2 , Motohide Tamura1,2,3 , Masao Saito2 , Nobuhiko Kusakabe1 , Yasushi
Nakajima4 , Jungmi Kwon5 , Takahiro Nagayama6 , Tetsuya Nagata7 and Ken’ichi Tatematsu2
1

Astrobiology Center of NINS, 2-21-1, Osawa, Mitaka, Tokyo 181-8588, Japan; 2 National Astronomical Observatoryof Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; 3 Department of Astronomy, The University of Tokyo, 7-3-1,
Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan; 4 Hitotsubashi University, 2-1 Naka, Kunitachi, Tokyo 186-8601, Japan;
5Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku,
Sagamihara, Kanagawa 252-5210, Japan; 6 Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan; 7
Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
E-mail contact: r.kandori at nao.ac.jp
κIn the present study, the magnetic field scaling on density,|B|∝ρ, was revealed in a single starless core for the first15
time. The κ index of 0.78 ± 0.10 was obtained toward the starless dense core FeSt 1-457 based on the analysis of theradial distribution of the polarization angle dispersion of background stars measured at the near-infrared wavelengths.
The result prefers κ = 2/3 for the case of isotropic contraction, and the diﬀerence of the observed value from κ = 1/2 is
2.8 sigma. The distribution of the ratio of mass to magnetic flux was evaluated. FeSt 1-457 was found to be magneticallysupercritical near the center (λ ≈ 2), whereas nearly critical or slightly subcritical at the core boundary (λ ≈ 0.98).
Ambipolar-diﬀusion-regulated star formation models for the case of moderate magnetic field strength may explain
the physical status of FeSt 1-457. The mass-to-flux ratio distribution for typical dense cores (critical Bonnor–Ebert
sphere with central λ = 2 and κ = 1/2–2/3) was calculated and found to be magnetically critical/subcritical at thecore edge, which indicates that typical dense cores are embedded in and evolve from magnetically critical/subcritical
diﬀuse surrounding medium.

Accepted by ApJ
https://arxiv.org/pdf/1808.05327

The JCMT Gould Belt Survey: SCUBA-2 Data-Reduction Methods and Gaussian

23

The JCMT Gould Belt Survey: SCUBA-2 Data-Reduction Methods and Gaussian
23 Source
Recovery Analysis
Helen Kirk1,2 , Jennifer Hatchell3 , Doug Johnstone1,2 , David Berry4 , Tim Jenness5,6 , Jane Buckle7,8 ,Steve Mairs4 , Erik Rosolowsky9 , James Di Francesco1,2 , Sarah Sadavoy10 , Malcolm Curry5,11 , Hannah
Broekhoven-Fiene2 , Joseph C. Mottram12,13 , Kate Pattle14,15 , Brenda Matthews1,2 , Lewis Knee1 , Gerald
Moriarty-Schieven1 , Ana Duarte-Cabral16 , Sam Tisi17 and Derek Ward-Thompson14
1

NRC Herzberg Astronomy and Astrophysics Research Centre, 5071 West Saanich Rd, Victoria, BC, V9E 2E7,
Canada; 2 Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Victoria, BC, Canada
V8P 5C2; 3 Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, UK; 4 East Asian Observatory, 660 N. Aohoku Place, University Park, Hilo, Hawaii 96720, USA; 5 Joint Astronomy Centre, 660 N. Aohoku
Place, University Park, Hilo, Hawaii 96720, USA; 6 LSST Project Oﬃce, 933 N. Cherry Ave, Tucson, AZ 85719,
USA; 7 Astrophysics Group, Cavendish Laboratory, J J Thomson Avenue, Cambridge, CB3 0HE, UK; 8 Kavli Institute for Cosmology, Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK;
9
Department of Physics, University of Alberta, Edmonton, AB T6G 2E1, Canada; 10 Harvard-Smithsonian Center
for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA; 11 RAL Space, Rutherford Appleton Laboratory,
Harwell Oxford, Didcot, Oxfordshire, OX11 0QX, UK; 12 Leiden Observatory, Leiden University, PO Box 9513, 2300
RA Leiden, The Netherlands; 13 Max-Planck Institute for Astronomy, Konigstuhl 17, 69117 Heidelberg, Germany;
14
Jeremiah Horrocks Institute, University of Central Lancashire, Preston, Lancashire, PR1 2HE, UK; 15 Institute of
Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan; 16 School of Physics
and Astronomy, Cardiﬀ University, The Parade, Cardiﬀ, CF24 3AA, UK; 17 Department of Physics and Astronomy,
University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
E-mail contact: helenkirkastro at gmail.com
The JCMT Gould Belt Survey was one of the first Legacy Surveys with the James Clerk Maxwell Telescope in Hawaii,
mapping 47 square degrees of nearby (< 500 pc) molecular clouds in both dust continuum emission at 850 µm and450 µm, as well as a more-limited area in lines of various CO isotopologues. While molecular clouds and the material
that forms stars have structures on many size scales, their larger-scale structures are diﬃcult to observe reliably in thesubmillimetre regime using ground-based facilities. In this paper, we quantify the extent to which three subsequentdata-reduction methods employed by the JCMT GBS accurately recover emission structures of various size scales,in particular, dense cores which are the focus of many GBS science goals. With our current best data-reduction
procedure, we expect to recover 100% of structures with Gaussian sigma sizes of ≤30′′ and intensity peaks of at least
five times the local noise for isolated peaks of emission. The measured sizes and peak fluxes of these compact structures
are reliable (within 15% of the input values), but source recovery and reliability both decrease significantly for larger
emission structures and for fainter peaks. Additional factors such as source crowding have not been tested in our
analysis. The most recent JCMT GBS data release includes pointing corrections, and we demonstrate that these tend
to decrease the sizes and increase the peak intensities of compact sources in our dataset, mostly at a low level (several
percent), but occasionally with notable improvement.
Accepted by ApJS
https://arxiv.org/pdf/1808.07952

16https://arxiv.org/pdf/1701.05953

25

25

Dust segregation in Hall-dominated turbulent protoplanetary disks
Leonardo Krapp1 , Oliver Gressel1,2 , Pablo Benı́tes Llambay1 , Turlough P. Downes3 ,Gopakumar Mohandas1,2 and Martin E. Pessah1
1

Niels Bohr International Academy, The Niels Bohr Institute, Blegdamsvej 17, DK-2100, Copenhagen Ø, Denmark
2
Kavli Institute for Theoretical Physics, University of California, Santa Barbara 93106, USA
3
Centre for Astrophysics & Relativity, School of Mathematical Sciences, Dublin City University (DCU), IrelandE-mail contact: krappleo@nbi.ku.dk
Imaging of dust continuum emitted from disks around nearby protostars reveals diverse substructure. In recent years,
theoretical eﬀorts have been intensified to investigate in how far the intrinsic dynamics of protoplanetary disks (PPDs)
can lead to such features. Turbulence in the realm of non-ideal magnetohydrodynamics (MHD) is one candidate for
explaining the generation of zonal flows which can lead to local dust enhancements. Adopting a radially-varying
cylindrical disk model, and considering combinations of vertical and azimuthal initial net flux, we perform 3D nonideal MHD simulations aimed at studying self-organization induced by the Hall eﬀect in turbulent PPDs. To this end,
new modules have been incorporated into the Nirvana-iii and fargo3d codes. We moreover include dust grains,treated in the fluid approximation, in order to study their evolution subject to the emerging zonal flows. In the regimeof a dominant Hall eﬀect, we robustly obtain large-scale organized concentrations in the vertical magnetic field thatremain stable for hundreds of orbits. For disks with vertical initial net flux alone, we confirm the presence of zonal
flows and vortices that introduce regions of super-Keplerian gas flow. Including a moderately strong net-azimuthal
magnetic flux can significantly alter the dynamics, partially preventing the self-organization of zonal flows. For plasmabeta-parameters < 50, large-scale near-axisymmetric structures develop in the vertical magnetic flux. In all cases, wedemonstrate that the emerging features are capable of accumulating dust grains for a range of Stokes numbers.
Accepted by ApJ.
http://arxiv.org/pdf/1808.07660

27

27

Revisiting the pre-main-sequence evolution of stars II. Consequences of planet formation
on stellar surface composition
Masanobu Kunitomo1,2, Tristan Guillot3 , Shigeru Ida4 and Taku Takeuchi5
1

Department of Earth and Planetary Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113- 0033,
Japan; 2 Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan; 3 Laboratoire Lagrange, UMR 7293, Université Côte d’Azur, CNRS, Observatoire de la Côte d’Azur, 06304 Nice CEDEX 04,
France; 4 Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551,
Japan; 5 Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku,
Tokyo 152-8551, Japan
E-mail contact: kunitomo at eps.s.u-tokyo.ac.jp
We want to investigate how planet formation is imprinted on stellar surface composition using up-to-date stellar
evolution models. We simulate the evolution of pre-main-sequence stars as a function of the eﬃciency of heat injection
during accretion, the deuterium mass fraction, and the stellar mass. For simplicity, we assume that planet formation
leads to the late accretion of zero-metallicity gas, diluting the surface stellar composition as a function of the massof the stellar outer convective zone. We adopt 150M⊕(M⋆ /M⊙ )(Z/Z⊙ ) as an uncertain but plausible estimate of themass of heavy elements that is not accreted by stars with giant planets, including our Sun. By combining our stellar
evolution models to these estimates, we evaluate the consequences of planet formation on stellar surface composition.
We show that after the first ∼0.1 Myr, the evolution of the convective zone follows classical evolutionary tracks withina factor of two in age. We find that planet formation should lead to a scatter in stellar surface composition that islarger for high-mass stars than for low-mass stars. We predict a spread in [Fe/H] of approximately 0.02 dex for stars
with Teﬀ ∼ 5500 K, marginally compatible with diﬀerences in metallicities observed in some binary stars with planets.
Stars with Teﬀ ≥ 7000 K may show much larger [Fe/H] deficits, by 0.6 dex or more, compatible with the existence ofrefractory-poor λ Boo stars. We also find that planet formation may explain the lack of refractory elements seen in
the Sun as compared to solar twins, but only if the ice-to-rock ratio in the solar-system planets is less than ≈0.4 andplanet formation began less than ≈1.3 Myr after the beginning of the formation of the Sun.
Accepted by A&A
http://arxiv.org/pdf/1808.07396