星形成ゼミ・資料
Star Formation News Letter#331 8-14

August 28, 2020
Ray S. Furuya

00formation mechanisms it would be interesting to observe CH3CH2, but give
Seeds of Life in Space (SOLIS). X. Interstellar Complex Organic Molecules in the NGC
spectroscopic
studies on this species are needed.
1333
IRAS 4A outflows
Marta De Simone1 , C. Codella2,1 , C. Ceccarelli1 , A. López-Sepulcre3,1 , A. Witzel1 , R. Neri3 , N.
Balucani4,1 , P. Caselli5 , C. Favre1 , F. Fontani2 , B. Lefloch1 , J. Ospina-Zamudio1 , J. E. Pineda5 and
M. De Simone et al.: Seeds of Life in Space (SOLIS)
V. Taquet2

Accepted by Astronomy & Astrophysics

Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France; INAF, Osservatorio Astrofisico di Arcetri, Largo
https://arxiv.org/pdf/2006.09925

1

2

E. Fermi 5, 50125 Firenze, Italy; 3 Institut de Radioastronomie Millimetrique (IRAM), 300 rue de la Piscine, 38400
Saint-Martin d’Hères, France; 4 Dipartimento di Chimica, Biologia e Biotecnologie, Universit degli Studi di Peru要旨
gia, Perugia 06123, Italy; 5 Max-Planck-Institut für extraterrestrische Physik (MPE), Giessenbachstrasse 1, 85748
interstellar
Complex Organic
Garching, Germany
Molecules(iCOMs;Cを含む, at gmail.com
E-mail contact:marta.de.smn>6原⼦からなる)をNGC1333
Context. The interstellar Complex Organic Molecules (iCOMs) are C-bearing molecules containing at least six atoms;
IRAS
4A分⼦流の衝撃波痕跡に
two mainapproaches of their formation 1are invoked: a direct formation in the icy 1
mantle of the dust grains, or
through the reaction in gas phase of released grain mantle species. The shocked gas along outflows driven by low-mass
対してNOEMAで探査(4”分解能)
1 how the iCOMs can be formed, as the composition
5
protostars is a unique environment to studyof the dust mantles is6
sputtered into the gas phase.
1material associated with low-mass protostellar outflows
9
CH
CHchemical
3OH,
3CHO, NH
2CHO,in shocked
Aims.
The
richnesshas been so far studiedCH
分流ローブ
in theprototypicalblue shifted outflow to investigate the iCOMs formation routes. To understand whether the
3OCH3を初検出;L1157
2,11,12
caseofL1157-B1
isunique,we
imagedandstudied the IRAS 4A outflows in the NGC 1333 star forming region.
ごとに化学的差顕著. Fig.1のMethods.
We used the NOEMA (NOrthern Extended Millimeter Array) interferometer as part of the IRAM SOLIS
SWは,
SEやNorthよりもricher(Seeds Of Life in Space) Large Program to image the large scale bipolar outflows driven by the IRAS 4A system inandin andiCOMs.
the 3brighter
mm band,we compared the observation with the GRAINOBLE+ astrochemical model.

Hot Corinos Chemical Diversity: Myth or Reality?

Marta De Simone , Cecilia Ceccarelli , Claudio Codella1,2 , Bri
Mathilde Bouvier , Satoshi Yamamoto , Nami Sakai , Paola Case
Bertrand Lefloch , Hauyu Baobab Liu , Ana López-Sepulcre1,10 ,and Leonardo Testi

Results. We report the first detection, in the IRAS 4A outflows, of several iCOMs: six lines of methanol (CH3OH),
eight of acetaldehydeCorino,(CH3CHO), one of formamide (NH2CHO) and four of dimethyl ether (CH3OCH3), all sampling
化学的な差からHot
upper excitation energy up to ?30 K. We found a significant chemical differentiation between the south east outflow
4A2が駆動する分⼦流よりもFig. 1: Left: Overlap of the contour map of the 1.25 mm continuum emission from NGC 1333 IRAS 4 region in Perseus, observed
driven by the IRAS 4A1 protostar,withshowinga richer molecular content, and the north-south west one driven by thethe IRAM 30m antenna (Lefloch et al. 1998), with the map of SiO line (VLA observations; Choi 2005). Axes o↵sets are in
4A1が駆動する分⼦流のほうがh m by00
IRAS 4A2 hot corino. The CH3OH/CH3CHO
abundance
ratio =
is 03
lower
factor∼4=inthearcseconds fromSVS 13 (↵(2000)
29 3s.9 aand(2000)
31the160 8former;). Right:furthermore
Zoom in in the
IRAS 4A system with NOEMA00
若い.
ratio in the IRAS 4A outflows is lower
a factor ∼10
respect
to the values
found4A.
inAdifferent
hot corinos.
SOLISbyobservations.
Axeswitho↵setsare in arcseconds
from IRAS
spatial separationof 5 correspond to ⇠ 1500 au at a distanceof 299(Zuckeriset now
al. 2018).
The whitetrianglestomark
theanpositionof thesources 4A1
and 4A2, while the black triangles markConclusions. After L1157-B1, IRAS
4Apc
outflow
the second
outflowshowevidentchemicalcomplexity.
0
the species,
position ofthe
theastrochemicalsources 4B and 4B
in Table2). Theblack crosses markreproduced
the analyzed positions in the outflows (SE,
Giventhat CH3OH is a grain surfacegas(coordinatesphase model
run with
GRAINOBLE+
CH
3OHを中⼼とする, 分⼦流のSW, North and As; coordinates in Table 2). The dashed blue and red arrows indicate the direction of the blue– and red–shifted 4B
our observation assuming that acetaldehyde
is formed mainly through the gas phase reaction of ethyl radical (CH3CH2)
衝撃波痕跡の化学を理解するた outflow (from the HCN observations of Choi 2001) and of the 4A ones. The contour map represents the iCOMs emission at 3 mm inand atomic oxygen. Furthermore, thetheIRASchemicaldifferentiation
twotheoutflows
the IRAS
4A1 for methanol whose contours
4A outflows(this work).between
For all thethe
iCOMs
contourssuggests
start at 3 thatwith stepsof 1 , except
めには,
さらに若い分⼦流をサ
outflow islikely younger than the have
IRAS
4A2
one.Further
investigationneededto constrain
the outflow.
steps
of 20
. The emission
distribution isisthefollowing:1) methanolthe(CHagein grey),
integrated over the transitions 20,2 10,1
3 OHofA, 20,2 shocks
10,1 E are
and 2necessary.
1 1,1 EmJy/beam
km/s;constraints
2) acetaldehyde(CH3CH3CHO
CHO, in magenta), here in the 50,5 40,4
1,2
ンプルにCH
CH2の観測が必要.
In addition, 3observationof even younger
Inwithorder =to75provide
strongon theemission with
= 11mJy/beam
km/s;formamide(NH41,4known,
31,3 emission
2 CHO, in green),
formation mechanisms it would be A
interesting
to observe
CH3CH2,but3)giventhat its
frequencies
are not
future with = 10 mJy/beam km/s;
dimethyl ether (CH3 OCH3 , in blue), 41,4 30,3 emission with = 9 mJy/beam km/s. The synthesized beams for the formamide line
spectroscopic studies on this species
are needed.
(green,⇠ 400 ) and for the other species (black, ⇠ 200 ) are indicated in the lower left corner. The primary beam (⇠ 5200 ) is shown with10

a dashed grey circle.
Accepted by Astronomy & Astrophysics

01he gas phase at the second step of the model. These values
composition.
As shown
re based on previous observations
towards L1157-B1(Codellaby the modelling of section 6, a smaller(/H)
molecules
injected
abundancest al. 2017).
density or a 5younger
age of the 4A1 outflow with respect to the
解析の流れ

CO2
H2 O
molecules
CO2OCS
H2 OH2 COOCSNH3H2 CO
NH3

3 ⇥ 104A2 onewould
explain the observed CH3 OH/CH3 CHO di↵er4
2 ⇥ 10 (/H)
injected
abundances
diagram”(左)からそれぞれの分⼦にence. 2Specifically,
if the two
outflows are very young and 4A1 is
6 “Rotation
3 ⇥ 10 ⇥5 10
younger
200exyr,then this⇨would
explain why its ratio ⇨1 ⇥4 than
10 6 about
ついてT
とN推定
N⽐から相対存在⽐推定
2 ⇥ 105
is2larger
2 ⇥6 than
10 the 4A2 one (see Figure 6).
⇥ 10
化学進化モデルと⽐較
6
Unfortunately,
our observations did not have enough1 ⇥ 102 ⇥ 10 5 lines to allow a meaningful non-LTE analysis to demethanol

rive the volume density, 今回の化学進化モデル
so we do not know if the density in the
4A1 outflow is lower than in the 4A2 outflow. With a non-LTE
気相反応
ダスト表⾯反応
on SO
et al.OH)(2019)
suggestthatSW
there
is Northno sig-from left to right; Lower panels:
2 , Taquet (CH: Upper panels: Rotationalanalysis
Diagramsof methanolin+outflow
SE,
and
3
nificantdi↵erence
in density between the outflow driven by 4A1
onal Diagrams of acetaldehyde(CH
3 CHO) in outflow SE, SW and North. The parameters Nup , gup , and Eup are the column
and theofone
from 4A2.
On thehand,
a typicaly, the degeneracy, and the energy
the upper
level. 新しい点
The
errorotherbars onln(Nassuming
up /gup ) are computed by taking the calibration error
velocity
oflines
100 represent
km/s,
wethe
estimate
integrated flux (15%) intoshockaccount.
The redbest fits.a kinematical age of• 塵サイズ分布を考慮⇠200 yr for the 4A1 outflow which has a very short extent; thisseemswithto thesupportthe younger
ageforofeach
4A1outflow
hypothesis.
4: Results of the LTE analysis
Rotational
diagrams,
peaks,Furtherusing the observation with the NOEMA• multi-layer
formationof grainice
more,
Santangelo
etal.
(2015),
usinghighspatialresolution
X backend. In the last row are shown the values of the abundance ratio between methanoloband acetaldehyde for each outflow
servations of CO, SiO and SO,
showed that the 4A1 jet is fastermantlesthan the 4A2 one; this, combined with the smaller spatial exten• 塵の成⻑と破壊も考慮
sion again support the hypothesisthat 4A1 outflow is younger
Molecule
Outflow
SE
Outflow
SW ageOutflow
Region As(a) L1157-B1(b)than the 4A2 one. In favor of a di↵erentof the Northtwo outflows
14 is also
there
observed chemical
Ntot [10cm 2 ] the50(30)9(7) di↵erentiation
12(9)between the5-15
130(30)CH3 OH
two[K]
driving sources,
4A1 and23(18)4A2: the former18(8)is bright in theT
11(3)10-30(c)10.0(1.1)
IRAS
4A分⼦流における,Fig. 5: Contour maprotof the CH
OH/CH
CHO
abundance
ratio
3
3
14
2
continuum
lacks
iCOMs
line emission, exactly
the opposite] but
1.3(0.5)
0.9(0.6)
 (0.25-0.5)
0.7(0.3)
totstart
yearmap
afterofNtheof thecm
shockThe
x and y0.6(0.4)
ig.atCH
5:1000
ContourtheCH[10abundance
ratio
3 OH/CH
3 CHO passage.
3 CHO
[CH
8 y
6 13(7)of 4A2(e.g.
López-SepulcreOneof
the possible
ex3OH]/[CH
3CHO]は
Tabundances[K]
23(19)
10-30(c)8(1)
t 1000
yeartheafter
the startpassage.
Thex andaxis areinjectedof methanol
[4
⇥9(2)
10
, 4 ⇥ 10 et] al. 2017).
rot of the shock
8
6
14
2
planationfor⇥ethyl
this
is 2thesmallerhot corino
which
xisandare thethe parent
injectedmolecule
abundancesof methanol10, 4situation⇥ 10 CH] 3 CHacetaldehyde,
radicalNtot of[10cm ][40.5
 0.7
1.6(0.7)
1.0(0.4)
3
他のclass
0 size,hot corinos
9 molecule
7 of acetaldehyde, ethyl radical CH3 CH2
CH
OCH
3
3
nd[4theparent(c)⇥ 10 , 4 ⇥ 10 ],Trespectively.
Themeasured
to ageac- of
could
also
imply amethanol
younger
and this19
agrees with the[K]
11
164A1,とも異なる.
10-30Fig.
9
7: Abundance
ratios between CH3 OH and CH3 CHO (Botrot
7↗
4 ⇥etaldehyde
10 9 , 4 ⇥ 10abundance], respectively.
Themeasuredmethanoltoac(8ratio youngerof 14
North andSW
outflows
20)
2
age
of itsoutflow too. 0.02
Ntot ofand
[10
cmone
] outflows
 0.02
 0.020.03(0.02)
tom panel), –CH3 OH and CH3 CHO column density (Upper
taldehyde
abundance
North(38 50)(8in 20)
falltheorange ratio
band
the and
SE SW
the green
NHin2 CHO(c)
In summary,thedi↵erent
CH3 OH/CH3 CHO 19
abundance ratio(38covered
allband;in theL1157-B1
orange band
the SE250)
one50) inbythe
Tand
[K]
11
10-30panel)–compared
to di↵erent sources for which the emitting sizerot (130value
isthegreen
blue band 16⇨ IRAS 化学的性質の差
(d)
(130
and;
L1157-B1
value
250)
is
covered
by
the
blue
band
measured in the 4A1 and 4A2 outflows is unlikely caused by a has been estimated via interferometric observations: the values
CH OH(Codella
et al. 2019).
Codella et3 al. 2019).
ではなく,
hot corinosの44(5) composition
11(3)of the17(3)
190(60)di↵erent grain mantle
two outflows,
because 20in the outflows
of IRAS 4A (this paper), in the outflow of L1157CH3 CHO
3
the
more
extended
4A2
outflowshowsnosignificant
variation
CH
サイズ差による, 密度差 B1 (Codella et al. 2019), the Class I source SVS 13A (Bianchi
a 3OHが気相で⽣成と仮定し, 衝撃波通過後10Region whereformamide
andthedimethyl
ether thatemitsacetalde(Ceccarelli et al. 2017);
Finally,
we
ran
a
model
with
assumption
this
ratio
over
scale observations;of about 6000 au. On the contrary, the et al. 2019), and the Class 0 sources, in decreasing order of boloFinally,
weCodellaran aOHに対するCH
model
withofthe
assumptionthat aacetaldeb
yearsのCH
From
al.the(2019)
basedoninterferometricに起因か？
3 eton3CHOの存在量(の逆hydeissynthesizedicemantlesandinjected
directly
into
yde cis synthesized on the ice mantles
and injected
directly into
observed
CH
OH/CH
CHO
abundance
3
3
Fixedrotationaltemperatureused
to derive a range of possible Ntot ; ratio is consistent with metric luminosity, Barnard1b-S (Marcelino et al. 2018), HH212gas
phase
at
the
passageoftheshock.
he the
gas
phase
at
the
passageoftheshock.
⽐をカラー表⽰)dthe scenario
in bestwhich(i) the densities
4A1 outflow
youngerthat(and,Abundance Ratio computed
dividing thefit column
derivedisassuming
the contwo species
tracing the
same
mmare
(Bianchiet al.
2017; Codella et al. 2019), IRAS 4A2 (Taquetgas with the same properties(see text).
sequently,
faster) than the 4A2 one and (ii) in both outflows ac- et al. 2015; López-Sepulcre et al. 2017), L483 (Jacobsen, StefModel
results⇨
IRAS
4A分⼦流は,etaldehyde
L1157とは明らかに異な.2.6.2.
Modelresults
is synthesized in the gas phase. The major reaction fen K. et al. 2019), IRAS 16293-2422B (Jørgensen et al. 2016),
Figure5 shows
the contourmap
theCH3 OH/CH
CHO
abun- and ethyl radical. The gas-phase CepE-mm (Ospina-Zamudio et al. 2018). The outflow values are
る.5 グレインあるいはガスの密度の違いに起因？
betweenoxygenigureshows
the contour
map isof thattheofCH
CHO3abun3 OH/CH
3 atomicModeldescription
cloudwith a given
time dependent
profile. Additionally,dance
at 1000
the shockpassage,
as aalsofunctionof withance
ratioratioat 1000
yearsyears
afterafter
thesynthesis
shockpassage,
as a functionof agrees
hypothesis
theoreticalquantumchem- physical
shown
with
redgrains,(pink multifor CH3 CHO) markers, the hot corinos in
the new code allows a distribution of size for thehe theinjectedmethanoland ethylradical,assumingthat acetaldeinjected
methanoland ethylradical,assumingthat acetalde- et al.
istry
studies(Enrique-Romero
2016,2019).
Thus,
although
NOBLE+
issynthesizeda gas–grain
model
simulatingthechemicalblue growth(cyan forusing diamonds for the outflows, dotsyde
is entirelyin theNote thatthecho3 CHO),ofhyde
is entirely
synthesized
ingas
thephase.
gasphase.
Notethat
the cho- layer formation of the grain ice mantle,
andCH
depletion
terrestrial
laboratory
experiments
show
that
acetaldehyde
can
be
ion
of
gas
and
ices.
It
is
the
upgradedversionof
GRAINensen
ageage(1000yr) isof magnitudeof theofkinemat(1000yr)inisthe
in orderthe orderof magnitude
the kinemat- the ice, and desorption.
for Class 0 and star for the Class I source. The cyan band reprecalicalageageof L1157-B1(Podioetal.
2016;
Codella
et
al.
2017)
formedonthesurfacesofdust
grains(e.g
Bennettetal.
2005a,b;E,
initially
developedby
Taquetetal.
(2012a);inparticularof L1157-B1 (Podio et al. 2016; Codella et al. 2017)
the area
in which
In this work, we used a chemicalsents
networkof 522
speciesthe
andthe hot corinos values fall.
nd,likely,IRAS
4A outflows.First,
the
shows
that there
e-codedand improvedin terms
of figurecomputational
efficiency
and, likely,
IRAS
4A outflows.First,
figureshows
thatresults
there provide evidence that the gasÖbergettheal.
2009),
our
4

02

are
underestimatedby∼30%.
Therefore,
centimeter
observationsare
cruc
Hot Corinos Chemical Diversity: Myth or Reality?
census,and ,theirabundances
Marta De Simone
Cecilia molecular
Ceccarelli , Claudio
Codella , Brian E. Svoboda , Claire Chandler ,2(2,0)-2(1,1) E
24.9343829-7.2
0.97 × 0.95 (−12)19(3)
6.5(0.2) 3.3(0.6)
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0.9
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3.1(0.3)
0.9
6(2,4)-6(1,5) E
25.0181271-7.1
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25.01812
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25.12487
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25.12487
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0.95
(−21)
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25.29442106-7.0 50.96 × 0.94 (−11)13(3)
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8(2,6)-8(1,7) E Bouvier9(2,7)-9(1,8) E
25.54140127-7.0
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López-Sepulcre,31(2)
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E. 32(2)Pineda, Vianney
Taquet10(2,8)-10(1,9)
E127 25.87827
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26.31312175-6.9
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6.0(0.4) 4.9(0.9)
1.1
31(3)
6.8(0.1) 2.9(0.3)
0.9aSpectroscopic parameters by Xu et al. (2008) are from the CDMS (Cologne Database for Molecular Spectroscopy; Mller et al. 2005) molecular database.
要旨bparameters
byofXual. (2008)fitarefrom the CDMS (Cologne Database for Molecular Spectroscopy; Mller et al. 2005) molecular database.
Results
theetGaussianalgorithm.
cGaussianalgorithm.
ThefitRMS
is computed over each spectral window.
omputed over each spectral window.
10
iCOMsの検出で定義される, hot corinoは提Accepted by ApJ Letters

https://arxiv.org/pdf/2006.04484

唱から20年が経つが,同定された数は少ない.
疑問.1: なぜhot corinoは多く⾒つからないのか？ 疑問.２:hot corino連星では, なぜ化学的性質が⼤きく異なるのか？

Probing the physical conditions and star formation pro
S305
仮説：ダストの光学的厚さの⾼さゆえ, 輝線が観測されない.

L. K. Dewangan , Saurabh Sharma , Rakesh Pandey2 , S. del P
NGC 1333 IRAS 4A binaryに対してVLAで
Baug5 and S. R. Das6
12

24-26 GHz帯のCH3OH輝線探査. この周波数では, 4A1と4A2ともにhot corino的性質を⽰す.
3

Physical Research Laboratory, Navrangpura, Ahmedabad - 380 009,
Observational Sciences, Manora Peak, Nainital 263 002, India.; Instituto
4
ダスト熱輻射のセンチ波でのtau推定 ⇨ 4A1
Department of Astronomy and Astrophysics, Tata
InstituteofFundamen
でiCOM linesがミリ波では受からないことが5
400 005, India.; Kavli Institute for Astronomy
and Astrophysics, Pek
整合的に説明できる.
District, Beijing 100871, P. R. China.; 6 Indian Institute
of143
Space
Science
ダスト熱輻射のtauGHz
25 GHz1̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶4A1
>=1.6
記述なし
4A2
~0.3
記述なし

E-mail contact: lokeshd at prl.res.in

Figure 1.present
Bottom right panel:
IRAS 4A continuum emission
map multi-wavelength
at 25 GHz. First contour and steps correspondto 50σ (σ = 3µJy beam of). the GalacticWe
multi-scaleandobservations
tomrightpanels:
panel: CH
IRAS
4Avelocity-integrated
continuum emission
maptoward
at 25 GHz.
and steps
correspond(σ = 3µJybeam). (from 50σ
Other
OH
maps
IRAS First
4A incontour
color scale
overlappedwith tothe50σcontinuum(white)contours: CHvelocity-integrated
maps toward
IRAS 4Afromin color
scale
overlapped
continuum
contours
50σ
withOHsteps
of 170σ). The emission
is integrated-2 km
s Infrared
to 2 km s withwiththerespect
to the (white)v (∼ reveal
6.7 km s (from). Methanol
first
contour
O8.5V
and
O9.5V
stars.
imagesanextended
sphere-lik
170σ
).
The
emissionisintegrated
from
-2
km
s
to
2
km
s
with
respect
to
the
v
(∼
6.7
km
s
).
Methanolfirst
contour(green) and steps correspond to 3σ (σ=1.2 mJy beam km s ). The transition of the imaged line is reported in each panel. The black stars
03 e
teps
correspond
3σ(σ=1.2
mJy beam
km sbeams). Thethe imaged
line is(green)
reportedpanel.leftTheblack starsshow
the 4A1 to
4A2
positions.
Synthesised
fortransition
continuum
and lines
are inin eachthe lower
corner.
27K) andenclosing
theS305
Hofii(white)region
(size
∼5.5
pc;
age ∼1.7 Myr). The
C

C

3

3

−1

C

−1

C

−1

−1

−1

−1
−1

−1

sys

sys
−1

C

−1

C
−1

C

−1

C

the linear polarization position angles observed at above and
議論部分
below 100 GHz frequencies (Ko et al. 2020).
Although we cannot exclude that a real chemical differSect.
5.1 ”Isbetween
IRAS 4A1
a hot
ence exists
4A1
andCorino?”
4A2, the observations so far
100
K以上の領域あり(Sect.3参照とあるが,availablecannot support that hypothesis. 明⽰的な記述なし)
Centimeter obser⇨
yes of other iCOMs than methanol are necessary to settle
vations
this issue. This conclusion may apply to other binary systems
Sect.
”4A2 versus
4A1: arethey chemicallydifferent?”
where5.2
an apparent
chemicaldifference
is observed
using mm
明確な結論の記述なし
observations.
5.3. Are the iCOMs abundances in hot corinos
underestimated?
The dust absorption also affects the iCOMs line intensities
in 4A2. At 143 GHz τdust is 0.3, which leads to underestimate
the iCOMs abundances by about 30%. At higher frequencies,
this factor becomes more important; e.g. at 250 GHz, where
several hot corinos studies are carried out (see references in§1), the absorption factor would be 2.5, and at 350 GHz,
frequency where the most sensitive iCOMs search has been
carried out (e.g. Jrgensen et al. 2016), the absorption factor
would be 6. This behaviour also agrees with what alreadyfound in massive hot cores (e.g. Rivilla et al. 2017). Therefore, in order to derive reliable iCOMs abundances complementary cm observations are needed to estimate the dust absorption.

と最後に⾔っているだけ.

derestimated by the dust absorption.
Therefore, the difficulty in disco
could be because the searches ha(sub)mm wavelengths, where the du
not negligible. The suspected diffecoeval objects of the same binary s
verified at cm wavelengths, as well as
estimated from mm observations.
We conclude that centimeter obse
are of paramount importance for the
future, next generation instruments
lenght regime, such as ngVLA (MSKA (Codella et al. 2015), could be
way to identify hot corinos and certai
facilities to study them.

ACKNOWLEDGM

We thank the referee P.T.P Ho foand suggestions. This work has
the European Research Council (ERUnion’s Horizon 2020 research andfor the Project “The Dawn of Orga
grant agreement No 741002. It was
PRIN-INAF 2016 The Cradle of Life

04

C/ C ratios increase with ζ because of secondary photons and cosmic-ray rea
Carbon isotopic fractionation in molecular clouds

Accepted
A&A
Laura Colzi1,2by, Olli
Sipilä3 , Evelyne Roueff4 , Paola Caselli3 and Francesco Fontani2
Università degli studi di Firenze, Dipartimento di fisica e Astronomia, Via Sansone 1, 50019 Sesto Fiorentino, Italy;
https://arxiv.org/pdf/2006.03362.pdf
2INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125, Florence, Italy; 3 Max-Planck-Institüt für
1extraterrestrische Physik, Giessenbachstrasse 1, D-85748, Garching bei München, Germany; 4 Sorbonne Université,
要旨
Observatoirede Paris, Université PSL, CNRS, LERMA, 92190 Meudon, France

isotope-selective
photodisscociationと低温でのisotopic交換反応を考慮した,
E-mailcontact:
at gmail.com
Seeds
oflcolzi.astroLifeinSpace (SOLIS). X. 化学進化モデルにおいInterstellar Complex OrgてCの同位体⽐は理論的に研究されてきた.
C-fractionation
has been4A
studiedoutflows
from a theoretical point of view with different models of time-dependent chemistry,
1333
IRAS
includingboth isotope-selective
photodissociation andlow-temperature isotopic exchange reactions. Recent chemical
最近の理論研究から,
低温でのisotopic交換反応によってCが窒素化合物にdepletionすることが⽰され
13modelspredictthatthe latter may
to a depletion of 132,1
C in nitrile-bearing species,with
1 leadabundance⽐の68よりも２倍ほど⼤きくなる.
1 12 C/13 C ratios two times
ており,
その結果,
12C/13C⽐はelement
12C/13C⽐Marta
Deelemental
Simone, C.
Codella, interstellar
C. Ceccarelli, theA.
López-Sepulcr
higherthantheabundance
ratio
of
68
in
the
local
medium.
Since
carbonisotopic ratio
14
15
は, N/ N⽐の推定の際に使われる,基本的な⽐であるため,理解を深める必要がある.
4,1
1
2
1 carbon
14 515is commonly used to
the N/ , NC.
ratiosFavre
with the double-isotope
method,,it B.
is important
to study
Balucani, evaluate
P. Caselli, F. Fontani
Lefloch, J. Ospin
今回, isotopic交換反応を新たに取り⼊れた,
HNC,weHCN
and CNにおける同
fractionationin detailassumptions. In this work
implemented
a gas-grain chemical model with
2 to avoid incorrect 気相反応モデルをつくり,V.
Taquet3 ̶ 2x107 cm-3の範囲について調べた.
位体⽐を10̶50
K, 2x10newisotopic exchange
reactionsand investigated their introduction in the context of dense and cold molecular gas. In
1213
weinvestigatedtheC/
C ratios of HNC, HCN, and CN using a grid of models, with temperatures
and1particular,
2
結論
Univ.
Grenoble
CNRS,
IPAG,
38000 Grenoble, France; INAF, Osser
3
7
densities
rangingfrom 10 to Alpes,
50 K and 2×10
to 2×10cm−3 , respectively.
13C + C13→ 12C + 13CC
13Cを交換.
13
122 反応を介して,
13• suggest
C原⼦を出発物質(?)とする分⼦の形成では,
3 C3
We
a
possibleC
exchange
through
the
+
C
→
C
+
CC
reaction,
whichこdoes not resultin dilution,
3
2
E. の反応は,Fermi(1)5,50125
Firenze,
Italy;
InstitutdeRadioastronomie
Millimetrique(I
13 13C存在⽐をあげる. (2) CO分⼦形成とCOがグレインへfreeze-outのあいだの化学進
but rather in C enhancement, for molecules that
4 are formed starting from atomic carbon. This effect is efficientSaint-Martind’Hères,France;Chimica,
Biologia
e Biotecno
in a化で特に有効.
range of time between
the formationof CO Dipartimento
and its freeze-out on di
grains.
Furthermore,
the parameter-space
12
13
5C/(=68)のexplorationshows,
onthat
the
C ratios
are このレンジを踏まえる
predicted
to extraterrestrische
be a factor
0.8–1.9 different Physik
from
12average,
3C⽐は,
と
•
⼤質量星形成領域の
C/1
local
value
0.8 of̶ nitriles
1.9 倍. ⇨gia, Perugia
06123,
Italy;
Max-Planck-Institut
für
(
12
13
14
15
the 14local
C/ C
of 68 for high-mass star-forming
regions.
This
result also affects the N/ N ratio: a value of 330
N/15N⽐は,よく使われる値=330に対して,260 ̶ 630
(up to1150)のレンジを取る.

Garching, Germany• 宇宙線イオン化率↗で, 12C/13C⽐も↗

9E-mail contact: marta.de.smn at gmail.com

Context. The interstellar Complex Organic Molecules (iCOMs) are C-bearing mo
two main approaches of their formation are invoked: a direct formation in ththrough the reaction in gas phase of released grain mantle species. The shocked g
protostars is a unique environment to study how the iCOMs can be formed, as th05
sputtered into the gas phase.

気相反応だけ(実線)では, after 2x105
yrs: COはダスト表⾯にfreeze-out始める. ⇦ 図1のキャプションは逆？(破線が下がっている)
図3左：CO depletionが進むと[He+]↗
(He+はcosmic-ray inducedイオン化で定率で⽣成される, COはHe+のmain
destruction partnerだから)
He+は気相中の残存COと反応を続けて[C+]↗（図1左）, C+はOを含む分⼦とではなく, 主にH2と反応し, [CH]↗ ⇦図1左では下がっている？
Fig. 1: Time evolution of C+ , C, CO, CH, and HCO+ (left panel ) and of CN, HCN, and HNC (right panel ) abundanceswith respect to H2 for the fiducial model with only gas-phase chemistry at work (solid lines) and with both gas-phaseand grain-surface chemistry at work (dashed lines).

[CH]↗の結果として, C2, C3, CN, HCN
実線は気相反応のみ, 破線は気相反応とダスト表⾯反応 and HNCの存在⽐も↗ (図1右の破線).
A&A proofs: manuscript no. C-fractionation-final-eps
CO freeze-out後は, HC3Nなどの炭素分⼦がfreeze-out指標(これはRuffle+97が既に指摘).
105yrsまではC-bearing分⼦の同位体存
在⽐にgas-grain反応の効果なし(図1右)だが, ~106 yrsでC, CH, CN, HCN,
and HNCにおける12C/13C⽐は最⼤(図3右). ⇦ この間, C原⼦の⼤部分はCOとして存在.

紫の縦線の左側はʼʼearly chemistry time”, 2つのオレンジの縦線のときの反応pathsを図4⽰す.

Fig. 2: Time evolution of the 12 C/13 C ratio for C, CO, CH and HCO+ (left panel ), and for CN, HCN, and HNC (rightFig. 3: Left panel: Time evolution of CN, C, CO, C2 , C3 , and He+ abundances with respect to H2 for the fiducial model.
panel ) for the fiducial model with only gas-phase chemistry at work (solid lines) and with both gas-phase and grain-surface
Right panel: Time evolution of the 12 C/13 C for CN, C, CO, C2 , and C3 for the fiducial model. The black
horizontal
chemistry at work (dashed lines).12In bothpanels the black horizontal dashed line represents the initial 12 C/13 C ratio of
13
dashed line represents the initial C/ C ratio of 68. In both panels, the vertical purple solid line represents the ”early
68.
chemistry time” as defined in the text, while the two vertical orange solid lines represent the two times (3×104 yr, and3×105 yr) that we have analysed and discussed in the text.
実線は気相反応のみ, 破線は気相＋ダスト表⾯反応
shows a 13 C-enhancement until the last million years of the carbon. Moreover, before 106 yr there is a short interval>106yrsでC-bearing分⼦における12C/
13C⽐↘(図3右)は, CO freeze-outの効果(CO freeze-outで気相中のmainreserverはCに変わる).
同じ効果↑は, <106yrsにおいても短い期間であるが, CとCN(図3左)とHCN(図なし)でも ⇨ 詳細議論

06ʼʼearly chemistry time”

!"#%

%

!"#%

%
!"#

#$!"#
!"#

%
%

#"
!$#

!$#

気相反応だけ(実線)では, after 2x105
yrs: COはダスト表⾯にfreeze-out始める. ⇦ 図1のキャプションは逆？(破線が下がっている)!$#!"#

#$!"#
%

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Fig. 4: Chemical pathways that distribute the two carbon isotopes in atomic carbon, C2 and C3 at 3×104 yr (left panel )and 3×105 yr (right panel ), for theA&A
fiducial
model.
Main creationand destruction reactions are highlighted in red, 12 C is
proofs:manuscript
no. C-fractionation-final-eps
represented in blue and 13 C is represented in green.
statistically expected value3 (2). This discrepancy could be
explained by a difference of 16 K in zero-point energy between the two species with respect to the main species C3 ,as shown in Table 2. The different position of the 13 C incarbon chains would probably lead to a higher abundanceof C13 CC with respect to 13 CCC for 27 K < T < 43 K be-

cause of the reaction C3 + 13 C → C13 CC + C + 43 K.
Another difference is that the symmetry factor f for thereaction C3 + 13 C → C13 CC + C is 1, while is 2 for thereaction C3 + 13 C → 13 CCC + C. We plan to upgrade ourchemical network to track the position of 13 C in molecules
and hence to study the possible roles of the different ZPEs.

3 Assuming a statistical distribution of 13 C in C3 , there are two
options to place it at the ends of the carbon chain and only one
at the center of the molecule.
Article number, page 8 of 24

紫の縦線の左側はʼʼearly chemistry time”, 2つのオレンジの縦線のときの反応pathsを図4⽰す.
Fig. 3: Left panel: Time evolution of CN, C, CO, C2 , C3 , and He+ abundances with respect to H2 for the fiducial model.
Right panel: Time evolution of the 12 C/13 C for CN, C, CO, C2 , and C3 for the fiducial model. The black horizontal
dashed line represents the initial 12 C/13 C ratio of 68. In both panels, the vertical purple solid line represents the ”earlychemistry time” as defined in the text, while the two vertical orange solid lines represent the two times (3×104 yr, and3×105 yr) that we have analysed and discussed in the text.

実線は気相反応のみ, 破線は気相＋ダスト表⾯反応

図3左：CO depletionが進むと[He+]↗
(He+はcosmic-ray inducedイオン化で定率で⽣成される, COはHe+のmain
destruction partnerだから)
He+は気相中の残存COと反応を続けて[C+]↗（図1左）, C+はOを含む分⼦とではなく, 主にH2と反応し, [CH]↗ ⇦図1左では下がっている？
[CH]↗の結果として, C2, C3, CN, HCN
and HNCの存在⽐も↗ (図1右の破線).
CO freeze-out後は, HC3Nなどの炭素分⼦がfreeze-out指標(これはRuffle+97が既に指摘).
105yrsまではC-bearing分⼦の同位体存
在⽐にgas-grain反応の効果なし(図1右)だが, ~106 yrsでC, CH, CN, HCN,
and HNCにおける12C/13C⽐は最⼤(図3右). ⇦ この間, C原⼦の⼤部分はCOとして存在.
>106yrsでC-bearing分⼦における12C/
13C⽐↘(図3右)は, CO freeze-outの効果(CO freeze-outで気相中のmainreserverはCに変わる).
同じ効果↑は, <106yrsにおいても短い期間であるが, CとCN(図3左)とHCN(図なし)でも ⇨ 詳細議論

07Fig. 5: HN12 C/HN13 C ratio as a function of nH , for different temperatures, at t1 (top right panel ), t2 (bottom left panel )and t3 (bottom right panel ). The large pink circles in the bottom panels represent the result of the model that simulates
the5: physicalconditionsin theof temperatures,the pre-stellar
Danielet al. (2013). The HN12 C/HN13 C ratio
Fig.
HN12 C/HN13 C
ratio as a functionof nHcenter, for different
at t1 (topcore
right B1b
panel ), observedt2 (bottom left by
panel
)
and
t3 (bottom rightpanel ). Theetlarge
circles inisthebottom panels represent
result of
the modelthat Note
simulates
observedby Danielal.pink(2013)
represented
by thethedark
green
star.
that観測との⽐較
the error bar is within the symbol. In all
1213
the physical conditions in the center of the pre-stellar core B1b observed by Daniel et al. (2013). The HN C/HN C ratio
chemistrytime, t2 =star-forming
2xt2, t3 = 10t1
the panels
purpledashedlines
represent
therange
of densities
ofはearly
the sampleof high-masst1
observedby Danielthe
et al.two(2013)verticalis represented
by the darkgreen star.
Note thatthe error bar
is within
the symbol.
In all12 C/13 C ratio of 68.
thepanels thetwo vertical purple
dashed3.2.2,
lines represent
the rangeof densitiesof the sampleof high-massstar-forming
regiondescribed
in
Sect.
and
the
black
horizontal
dashedlines
represent
theinitialT=
10[K]での振る舞いは他と異なる
12
13
region described in Sect. 3.2.2, and the black horizontal dashed lines represent the initial C/ C ratio of 68.
Table 5: 12 C/1312
C ratios13for different molecules (C3 , C2 , C, cm−3 , and the temperatures are 10, 20, 30, 40 and 50 K.
12 C/HN
13 C, temperatures are 10, 20, 30, 40 and 50 K.
Table
5:
C/HNC)Cforratios
for different(C73show, C2the, C,
CO, CN, HCN, andthree different
times in the molecules
cm−3
, and
the
Figs. 5, 6, andbehaviour
of HN
12
13
12
13
fiducial”early chemistrytime” (secondrow), t1 , different
12 C/HN13 C,
H CN/H CN,
and inCN/theCN, respectively,
as a6,
function
CO, model:
CN, theHCN,
and HNC)for three
times
Figs.
5,
and
7
show
the
behaviourofHN
as defined in the text, and the times before and after t1 of nH and for different temperatures.
In particular, it can
12 CN/H
13 CN,
fiducialthe(secondthat
we have model:
discussed inthe ”earlytext (firstchemistry
and third row,time”
1 , forHdensities
be noted
that for row),
t1 and t2 tandhigherthan and 12 CN/13 CN, respectively, as a function
6
−3
12
13
respectively).
cm , theC ratiost tend to be higher for 10 K
as defined in the text, and the times 10
beforeandC/ after1of ThisnH isandforthedifferent temperatures. In particular, it canwith respect to higher temperatures.
because12
13Time we have discussed
C/ C
that
in the text (first
thirdrow, until
forwardandreaction(2) is efficient
K, together
beT<17.4
notedthat for t1 and t2 and for densities higher thanC3 C2 C CO CN HCN HNC
withthe
low-temperatureisotopicexchange
reactionC .
6−3 forrespectively).
+10
the3 12 C/13 C ratios tend to be higher for 10 K
3×104 yr
6 68 163 35 50
88
106
Then, most of the 13 C is in CO, HCO, andcmin C3 . ,It should
be noted that this trend is also different
on thet1 =1.6×105 yr 7 24 211 63 65
6876
withofdepending
respect
to higher temperatures. This is because the5density.
Thisisbecauseofthedefinition
t
:
for
a
density12
13
3×10 yr
6 11 81 64 57
50
79
1
Time
C/ ofC106 cm−3 t1 is the time just before
forwardreaction(2) is efficient until T<17.4 K, together
reaching thedip ofratiosHNC
that directly follows C3 , while for a
C3 C2 C CO carbon
CN isotopic
HCN
withthe low-temperature isotopic exchange reaction for C3 .
5 cm−3 t is the time whendensityof10
the dip in 12 C/13 C is1
413
yr exploration6 68 163 35 present
50 and88
106
follows thatof C3 . TheThen,higher themost
density,ofthetheC is in CO, HCO+ , and in C3 . It should
3.2. 3×10
Parameter-space
12
13
later the dip of lower C/ C with respect to t1 when most5
thatex-this trend is also different depending on the
t1 =1.6×10
yrthe analysis
7 24
63 of
65
68C is in the76
In thissection, we focus
on the 211
nitrile-bearing
the atomic
form of CO.be
Thenoted
most probablespecies CN,5HCN, and HNC in order to evaluate how reli- planation, following also what was described
in結論だけ利⽤したい⼈に便利かもしれない「まとめ」
Sect.
3.1.3,
density.
This
is because of the definition of t1 : for a density
yr of the 14 N/156N ratio
11based81
64
50
79
able3×10
the estimateson 12 C/13
C= is57
that there is a competition between the O
atoms
trans−3
106andcm
t1 is the time just before reaching the dip of
68 (Colzi et al. 2018a; Colzi et al. 2018b) are.
formed into CO and frozen out on ofgrains,those that08

OBINGPHYSICAL
CONDITIONSANDSTARFORMATIONPROCESSES
IN THE GALACTIC
ora suppression
the low-frequency
emissionby theRazin-Tsytovich
eff
ProbingTHE
the physicalconditions
and star offormation
processes
in theGalactic
HII
regionREGION S305
S305

Accepted by The Astrophysical Journal

1
22
2
4
1
2del Palacio3 , D. K. Ojha
3
4 3 , T.
4
5
L.
K.
Dewangan,
Saurabh
Sharma,RakeshPandey,S.
,P.
Benaglia. Dewangan,
Saurabh
Sharma,RakeshPandey,S.
delPalacio
,
D.
K.
Ojha
,
P.
Benaglia,T.
Baug
Baug5 and S. R. Das6
6
1

S. R. Das
https://arxiv.org/pdf/2006.03244.pdf
Physical Research Laboratory, Navrangpura, Ahmedabad - 380 009, India.; 2 Aryabhatta Research Institute ofObservational Sciences, Manora Peak, Nainital 263 002, India.; 3 Instituto Argentino de Radioastronomía, Argentina.;
4
Department of Astronomy and Astrophysics, Tata Institute of ABSTRACT
Fundamental Research, Homi Bhabha Road, Mumbai
5
400 005, India.; Kavli Institute for Astronomy and Astrophysics, Peking University, 5 Yiheyuan Road, Haidian
WeBeijingpresent
multi-scale
multi-wavelength
observationsof Trivandrum
the Galacticii region S305, which
6
District,
100871,P. R. China.; andIndianInstitute of Space Scienceand Technology,695547,HIndia.

Tidal tails of open star clusters as probes to early gas ex

is excited by massive O8.5V and O9.5V stars. Infrared images reveal an extended sphere-like shell1
2,3
Frantisek
DinnbierandPavel
Kroupa(extension
⇠7.5
pc;
at
T
=
17.5–27
K)
enclosing
the
S305
H
ii
region(size ⇠5.5 pc; age ⇠1.7
d
We present multi-scale and multi-wavelength observations of the Galactic H ii region S305, which is excited by massiveMyr).
observedin thesphere-like
Herschel
O8.5V
and TheO9.5Vextended
stars. Infrared
images reveal
an extended
shelltemperature(extension ∼7.5map
pc; atindicates
Td = 17.5–that the molecular
1 structure
I.Physikalisches
Institut,
Universität
zuobserved
Köln,
Zülpicher
Strasse77, D-509
of S305is heatedby pc;
theagemassive
O-typestars.structure
Regularly
spacedmolecularcondensations
27 environmentK) enclosing the S305
H ii region(size ∼5.5
∼1.7 Myr).
The extended
in the Herscheltemperature
indicatesthat
the molecularenvironmentof S305is heatedthe massive
O-typestars.
Regularly
and dustmap
clumpsareinvestigatedtowardtheedgesof thebyinfrared
where
the PAH14-16,
and H253115
emission
Strahlenund
Kernphysik,
University
ofshell,Bonn,
NussalleeBon
spacedmolecularcondensations
anddust clumpsline
are investigatedtowardthe edges of of
the aninfraredshell, where
the of molecular gas
is alsoobserved.
The
molecular
data
show
a
signature
expandingshellofmolecularMathematics
Physics,
AstronomicalInstitute,
V Holesovic
PAH and H2 emission is alsoFaculty
observed. Theline data showand
a signatureof an expanding
shell of molecular
gas
in
S305.
GMRT
610
and
1280
MHz
continuum
maps
revealoverdensities
oftheionizedemissionin S305. GMRT 610 and 1280 MHz continuum maps reveal overdensities of the ionized emission distributed aroundaroundtwo O-type
which
are
surrounded
horseshoeenvelope (extension
E-mailcontact:
dinnbierat
ph1.uni-koeln.de
twodistributed
O-type stars, whicharesurroundedby thestars,
horseshoeenvelope(extension∼2.3 pc).by
A themolecular
gas deficient⇠2.3 pc).
A molecularregion/cavity
is isidentified
towardcenter of the horseshoe
region/cavity
is identified
toward thegas
centerdeficientof the horseshoe
envelope, which
well traced with
PAH, Hthe
2 , molecular,
andenvelope,
dust emission.
The edgesof theinfraredwith
shellform
arefoundout
locatedfront dustof thehorseshoeclustersofthein thedensestparts
ofenvelope.
infrared
which
isStarwell
tracedPAH,
Hto2 ,bemolecular,andemission.
The Alledgesdarkof theclouds.
infrared T
theseoutcomes
provide to
the beobservational
evidence
offront
the feedback
ofhorseshoe
O-type stars in
S305. Moreover,non-thermal
shell
are foundlocated
in
the
of
the
envelope.
All
theseoutcomes
provideresidual gas, which has not formed stars yet. Gas expulsion
lowersthethegra
observational evidence of the feedback of O-type stars in S305. Moreover, non-thermal radio emission
manyspectralof11theindex
clusterThesestars inthenmove onis detected in S305unbinding
with an average↵ ⇠ stars.
0.45. The
variations↵, ranging
fromtheir
1.1 ow
fielddueof totheforminga tidaltail. optically-thicker
We investigatethermal
the formation
to 1.3, are explained
softGalaxy,synchrotron
emissionand either
emission
at high frequenciestoorexpulsion
a suppressionof the low-frequency
emissionby theRazin-Tsytoviche↵ect.
of primordial
gas under
variousscenariosof gas expulsiont
Subject headings: dynamicallydust, extinctionevolved– HII regions
ISM: individual
object (Shwhich
2-305) can–(age –>ISM:
100cloudsMyr)– galactic
star clusters,stars: formation – stars: pre-main sequence
E-mail contact: lokeshd at prl.res.in

We provide a semi-analytical model for the tail evolution. We find th
have different kinematic properties than the tails gradually forming due
1. INTRODUCTION
dense shell of cool neutral material between the ioshows non-monotonic expansion
with
time,
where
longerepochsof expan
tion
and
the
shock
fronts,where
starformationisassive OB-stars ( 8 M ) have a profound impact oncontraction. The tail thickness
andvelocity
dispersions
strongly,
but nouated
when
this material
becomesgravitationally
immediate environment through the radiative andble; andthe formation
massive stars
expected
times
minimaof tailthickness
velocity ofdispersions
areisgiven
onlyinanical energy they inject
fromoftheirformation
phase
particular scenario (e.g., Deharveng et al. 2010).
their death. Hence,and
these
haveproperties
the ability of thenotstarsby thecluster. The estimates provided by the (09

L. K. Dewangan et al.

S305S
S305N

1.28GHz 連続波#4#2

infrared shell

H alpha#4#2
ionized shell

S305S
S305E2

電波スペクトル指数
Figure 9. a) Overlay of the GMRT 610 MHz continuum contours on the 610 MHz gray scale map (resobox in Figure 8f). The GMRT 610 MHz continuum contour levels (in cyan) are 2.2, 3, 4.5, 6.5, 9.5, 12, 15-1.1から+1.3(左),右はそのエラーマップ
29, and 31 mJy beam(with ⇠ 0.46 mJy beam ). b) Overlay of the GMRT 1280 MHz continuum
1

S305E1cavityS305N

S305W5

S305W3
S305W2 Synchrotron +スペクトル指数が特にhard (<-0.6;紺⾊部分)は,S305W1
optically thick free-free emission
S305W4あるいはSynchrotron, 低周波側でRazin-Tsytovich effectによるsuppression

1

scale map (resolution ⇠ 1000 ⇥ 1000 ). The GMRT 1280 MHz continuum contour levels (in cyan) are 3, 4,
Probing the physicalconditions and star formation processes in the Galactic HII region S305
19
17, and 18 mJy beam 1 (with ⇠0.74 mJy beam 1 ). The GMRT 1280 MHz continuum level at 2.5 m
contour. A pink dashed box encompasses the area shown in Figures 11a, 11b, 11c, and 11d. c) Overlay of t
contours (at 2.5 and 10.5 mJy beam 1 ) on the H↵ image. In all panels, stars show the positions of tw
Figure 1a).

10

Figure 10. a) GMRT spectral index map (resolution ⇠1000 ) of S305 generated for pixels above 3 level in the 610 and 1280 MHz bands.
The GMRT 1280 MHz continuum emission is also shown by a dotted-dashed contour at 10.5 mJy beam 1 . Regions with non-thermal ↵ aregreenish-blue, while regions consistent with thermal emission are red-yellow. b) GMRT spectral index error map of S305. In both panels,stars show the positions of two massive O-type stars (see also Figure 1a), and a big circle (in white) highlights the central region of S305.

【解析の流れ】 southern binar
Taurus, arguingIs that
it is a protostar ejected from the embedded
T Tauri North a ‘Classical’ T Tauri star?

Is T Tauri North a ‘Classical’ T Tauri star?

Flores, B. Reipurth , and M. S. Connelley 6
1
Acceptedby C.ApJ
Christian Flores, Bo Reipurth1 and Michael S. Connelley1
1

1

1

1

分光
⬇

Flores e

輝線幅から星の回転速度
Institute for Astronomy, University of Hawaii at Manoa, 640 N. Aohoku Place, Hilo, HI⬇ 96720, USA
1 Institute for Astronomy, University of Hawaii at Manoa, 640 N. Aohoku Place, Hilo, HI 96720, USA

https://arxiv.org/pdf/2006.10139.pdf(Received March 22, 2020; Revised April 28, 2020; Accepted June 16, 2020)
E-mail contact: caflores at hawaii.edu

Submitted to ApJ

円盤からのコンタミを評価&除去⬇

We present high-resolution H- and K-band spectroscopic observations of the archetypal
T Tauri starincl.込みの星の回転速度
ABSTRACTISO-ChaIa weakly-accretingstellarobjectwithfielda⬇
Synthetic spectral52:
modeling
is usedto derive the K-bandyoung
temperature,surface gravity,
magnetic
We present high-resolution H- and K-band spectroscopic observations of the archetypal T Tauri star
モデルから求まるのは,表⾯温度
rotational
velocity
for thisstar.is The
spectroscopic
temperature
measured
is TK−band
1
2 toK-band
3
4
5,6 = 3976
T
Tau
North.
Synthetic
spectralmodeling
usedderivetheK-bandtemperature,surfacegravity,A.
, C.F.
Manara, J.M.
Alcalá
, K. observations.
Biazzo, L.
et al.
重⼒加速度
is ∼ Frasca
1000
coolerthanthetemperature
fromspectroscopic
optical
OurVenuti
K-bandtemperatur
magnetic
fieldKstrength,androtational
velocity for this measured
star. The K-band
temperature
磁場強度
measured
is TK-band=confirmed
3976 ± 90K, using
which isequivalent⇠ 1000 K cooler
than line
the temperature
measuredfrom
1for T Tau
N
is
width
ratio
vs.
temperature
relationsinCatania,
the H-bandI
INAF–
Osservatorio
AstrofisicodiCatania,
via
S.
Sofia
78,
95123
K-band verling
optical observations. Our K-band temperature measurement for T Tau N is confirmed using equivalentTH−band = 4085 ± 155K is derived. This optical vs. IR temperature difference is interpreted as coolo3
(仮定はsolar⾦属量,
磁場強度⼀定)
width
line
ratio
vs.
temperature
relationsintheH-band,
from
which
a
T
=
4085
±
155K
is
H-bandtory,
Karl-Schwarzschild-Strasse
2, 85748
Garching
bei München,
Germany;I
both,coveringasignificant
part
of
the
surface
of
T
Tau
N.
The
gravityderived
for
T
Tau
N
log
g
=
derived. This optical vs. IR temperature di↵erence is interpreted as cool or hot spots, or both, 4
covering
via ofMoiariello,
16,
Italy;
INAF–星質量は求まらない？
Osservatorio
aCapodimonte,
significant
partof thesurfaceof nearly
T Tau N.every
The gravity
derivedforNapoli,
Tau N logofg=± 0.14is T Tauri
lower
than
the
gravityother80131
star inaT sample
243.45classical
stars in Taurus.AstC
lower
than the gravity
nearly every
otherwithstar inmagnetica sample5 ofstellar
24 classicalT Tauri stars models,in Taurus. we find the age of T Tau N
temperatureand ofgravity
results
evolutionary
00078
Monte
PorzioCatone,Italy;
NASAAmes
ResearchCenter, Moffett Blvd
Combining these temperature and gravity results with magnetic stellar evolutionary models, we find
1 Myr
old.
These
results suggestthat T Taudi
Nsuggestisin anearlier
evolutionary
stageMoogStokes
than mostclassical
T
Figurebetweenmodelswith di↵ertheage of T
N to be less than 1Astronomico
Myr old. These resultsthat T
Tau
N2.isComparison
in andelearlier
INAF– Tau
Osservatorio
Palermo,
PiazzaParlamento
1,
90134
P
(grey
insouthern
threeejected
wavelength
regions.
We see shortly
how the line-deptTaurus, arguing
is a protostar
fromthethatembeddedbinarysystemafter
evolutionary
stage thanthat
most itclassical
T Tauri starsejected
in Taurus,
arguing
it is line)
a protostar

E-mail
Acceptedcontact:
by ApJ antonio.frasca at inaf.it

from the embedded southern binary system shortly after its formation.
6

Flores et al.

substantially change as the temperature of the models vary. T
temperature of ⇠ 4000 K.

We report on the discovery of periodic dips in the multiband lightcurve of ISO-C
Chamaeleon I dark cloud. This is one among the peculiar objects that display ve
1. INTRODUCTION
Herbig 1953). The implication is that T Tau is located
ISO-ChaI
52: a weakly-accretingyoungstellarobjectwithdipper lightinfracu
their
UV continuum
and spectral
althoughtheypresent
aa remarkablevery lines,
close
to thesurfaceof its small
associatedglobule.
(1945) identified 11 irregular variable stars which
For a historicalaccount ofsee
1 di↵erent circumstellar
23
4 the T Tauriaphenomenon,
5,6
d optically-thickmuchalike, butother classesof disks.
We
haveanalyzed
VLT/X-Shooter
spectrum
A. Frasca, C.F. from
Manara, J.M.
Alcalá
,K.
Biazzo,L.
Venutietal.
Reipurth(2016).
les, and named them after T Tauri. In a now clas1
Based
on
blue
photographic
spectra, Catania,
Herbigfrom(1962)
thestellarparameters.
Theof dilatter,alongour2 campaignwper,Herbig(1962)
provideda detailed
analysis
INAF– Osservatorio
Astrofisico
Catania,
via
S.with
Sofia photometry
78, 95123
Italy;
European Sout
determined the spectral type of T Tau to be dG5e.3 Alpectsof theT Tauri phenomenon. While Herbig
tory,Karl-Schwarzschild-Strasse
2,85748
Garchingbei
München,Germany;
INAF – andOsservatorioA
literature,
haveallowed
us
to
model
the
spectralenergydistribution
to
estim
ready
more
than
half
a
century
ago
this
set
T
Tau
apart
fied the T Tauri stars in a restrictive manner, the4Capodimonte,
via
Moiariello,
16,
80131
Napoli,
Italy;
INAF
Osservatorio
di Roma,
V
from
most
other
T
Tauri
stars,–of
whichalmostas a Astronomico
rules innerused today
in a morerelaxedway, describing
and
outer
disk.
From 5thearerotational
periodthestar/disk
systemof
3.45
11
K- and M-stars. Since the work of Herbig, T Tau
Keywords:
infrared: stars - stars: formation - stars: pre-main sequence - stars: magnetic fields https://arxiv.org/pdf/2006.10139.pdf
techniques: spectroscopy - techniques: synthetic spectra

Figure 2. Comparison between MoogStokes models with di↵erent temperatures (color lines) vs. the spectrum of T Tau N(grey line) in three wavelength regions. We see how the line-depth ratio of the Si/Ti (left), Sc/Na (middle), and Fe/Ti (right)
substantially change as the temperature of the models vary. The best match in all cases corresponds to a model with atemperature of ⇠ 4000 K.

00078visible
Monte
PorzioCatone,Italy;
opticallyyoung
low-massstars. The
term

NASA Ames Research Center, Moffett Blvd, Mountain View, CA

10Flores et al.

T Tau N

Figure 6. The left panel shows the position of T Tau N (yellow star) and a sample of 24 CTTS from Taurus (blue circles) in
the K-band temperature vs. surface gravity diagram. A sample-representative uncertainty of 90 K in K-band temperature and0.14 dex in gravity is shown in the upper-left part of the plot. The right panel show isochrones (solid blue), evolutionary tracks(dotted black), and luminosity curves (solid red) from the Feiden (2016) magnetic evolutionary models.

temperatures, it seems noteworthy that the earlier typestar T Tau N also has a larger temperature di↵erence
than the late K and M stars BP Tau and TW Hya.
An alternative explanation for the temperature discrepancy of T Tau N is that the optical temperature
measured for T Tau is a↵ected by emission from hot

It is beyond the scope of this paper to identify which ofthese scenarios, or a combination of both, could explain
the temperature di↵erence between optical and NIR observations for T Tau N. To answer such a question one
would require multi-wavelength and preferably simultaneous observations of T Tau N accompanied by a so-12

tail, the minima of tail thickness, and ve
Tidal tails of open star clusters as probes to early gas expulsion I:
This implies
A semi-analytic
modelthat the semi-analytic moda cluster of a given age and orbital parFrantiöek Dinnbier , Pavel Kroupa
with
a
more
extendedparameter
space
I.Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany
1

2, 3

1

e-mail: dinnbier@ph1.uni-koeln.deHelmholtz-Institut für Strahlen- und Kernphysik, University of Bonn, Nussallee 14-16, 53115 Bonn, Germany
e-mail: pavel@astro.uni-bonn.de
3Charles University in Prague, Faculty of Mathematics and Physics, Astronomical Institute, V Holeöovi kách 2, 180
00 Praha 8, Czech Republic
2

Accepted by Astronomy & Astrophysics

https://arxiv.org/pdf/2006.14087
Received August 25, 2019; accepted June 17, 2020
ABSTRACT
Context. Star clusters form out of the densest parts of infrared dark clouds. The emergence of massive stars expels theresidual gas, which has not formed stars yet. Gas expulsion lowers the gravitational potential of the embedded cluster,
unbinding many of the cluster stars. These stars then move on their own trajectories in the external gravitational fieldof the Galaxy, forming a tidal tail.
Aims. We investigate, for the first time, the formation and evolution of the tidal tail forming due to expulsion ofprimordial gas. We contrast the morphology and kinematics of this tail with that of another tidal tail which forms
by gradual dynamical evaporation of the star cluster. We intend to provide1predictions which can differentiate thedynamical origin of possibly observed tidal tails around dynamically evolved (age & 100 Myr) galactic star clusters by
the Gaia mission. Such observations might estimate the fraction of the initial cluster population which gets releasedin the gas expulsion event. The severity of the initialgas expulsion is given by the star formation efficiency and the1time-scale of gas expulsion for the cluster when it was still embedded in its natal gas. A study with a more extended
parameter space of the initial conditions is performed in the follow up paper.
Methods. We provide a semi-analytical model for the tail evolution. The model is compared against direct numericalsimulations using nbody6. これまでよく研究されてきたevaparation
Results. Tidal tails released during gas expulsion have different kinematic properties than the tails gradually forming
due to evaporation, which have been extensively studied. The gas expulsion tidal tail shows non-monotonic expansion
with time, where longer epochs of expansion are interspersed with shorter epochs of contraction. The tail thickness andvelocity dispersions strongly, but not exactly periodically, vary with time. The times of minima of tail thickness and4
velocity dispersions are given only by the properties of the galactic potential, and not by the properties of the cluster.
The estimates provided by the (semi-)analytical model for the extent of the tail, the minima of tail thickness, andvelocity dispersions are in a very good agreement with the nbody6 simulations. This implies that the semi-analytic
model can be used for estimating the properties of the gas expulsion tidal tail for a cluster of a given age and orbitalparameters without the necessity of performing numerical simulations.

The JCMT BISTRO Survey:
NGC 1333

Yasuo Doi , Tetsuo Hasegawa2 , Ra

Department of Earth Science and As
3-8-1 Komaba, Meguro, Tokyo 153-8902
Natural Sciences, Osawa, Mitaka, Toky
Tokushima 770-8502, Japan; Institutemachi 1-1, Tokushima 770-8502, Japan
E-mail contact: lvferrero at unc.edu.ar
13

Key words. Galaxies: star formation, Stars: kinematics and dynamics, open clusters and associations: general14