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

August 28, 2020
Ray S. Furuya

00Seeds of Life in Space (SOLIS). X. Interstellar Complex Organic Molecules in the NGC
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
Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France; 2 INAF, Osservatorio Astrofisico di Arcetri, Largo
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 Perugia, Perugia 06123, Italy; 5 Max-Planck-Institut für extraterrestrische Physik (MPE), Giessenbachstrasse 1, 85748
Garching, Germany
1E-mail contact: marta.de.smn at gmail.com
Context. The interstellar Complex Organic Molecules (iCOMs) are C-bearing molecules containing at least six atoms;
two main approaches of their formation are invoked: a direct formation in the icy 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
protostars is a unique environment to study how the iCOMs can be formed, as the composition of the dust mantles is
sputtered into the gas phase.
Aims. The chemical richness in shocked material associated with low-mass protostellar outflows has been so far studied
in the prototypical L1157 blue shifted outflow to investigate the iCOMs formation routes. To understand whether thecase of L1157-B1 is unique, we imaged and studied the IRAS 4A outflows in the NGC 1333 star forming region.
Methods. We used the NOEMA (NOrthern Extended Millimeter Array) interferometer as part of the IRAM SOLIS(Seeds Of Life in Space) Large Program to image the large scale bipolar outflows driven by the IRAS 4A system inthe 3 mm band, and we compared the observation with the GRAINOBLE+ astrochemical model.
Results. We report the first detection, in the IRAS 4A outflows, of several iCOMs: six lines of methanol (CH3OH),
eight of acetaldehyde (CH3CHO), one of formamide (NH2CHO) and four of dimethyl ether (CH3OCH3), all sampling
upper excitation energy up to ?30 K. We found a significant chemical differentiation between the south east outflow
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 inh 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
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,Given that CH3OH is a grain surfacegas(coordinatesphase model
run with
GRAINOBLE+
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
throughthe2001)
gas phasereactionof Theethyl
radicaloutflow (fromthe HCNmainly
observationsof Choi
and of the
4A ones.
contourmap(CH3CH2)
represents the iCOMs emission at 3 mm inand atomic oxygen. Furthermore, thetheIRASchemicaldifferentiation
betweenthetwooutflows
suggests
that
the
IRAS
4A1 for methanol whose contours
4A outflows (this work). For all the iCOMs the contours start at 3 with steps of 1 , except
outflow is likely 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
In addition, observation of 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 witha dashed grey circle.
Accepted by Astronomy & Astrophysics

composition. As shown by the modelling of section 6, a smaller
density or a younger age of the 4A1 outflow with respect to the
4A2 one would explain the observed CH3 OH/CH3 CHO di↵erence. Specifically, if the two outflows are very young and 4A1 isyounger than about 200 yr, then this would explain why its ratio
is larger than the 4A2 one (see Figure 6).
Unfortunately, our observations did not have enoughmethanol lines to allow a meaningful non-LTE analysis to derive the volume density, so we do not know if the density in the
4A1 outflow is lower than in the 4A2 outflow. With a non-LTE
on SO
et al.OH)(2019)
suggestSE,
thatSW
there
is Northno sig-from left to right; Lower panels:
2 , Taquet (CH: Upper panels: Rotationalanalysis
Diagramsof methanol
in outflow
and3nificantdi↵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. 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⇠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
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 fasterthan the 4A2 one; this, combined with the smaller spatial extension again support the hypothesis that 4A1 outflow is younger
Molecule
SE of
Outflow
SW ageOutflow
Region As(a) L1157-B1(b)than the 4A2 Outflow
one. In favora 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,
4A2: the former18(8)is bright in theTrot
11(3)4A1 and23(18)10-30(c)10.0(1.1)
IRAS
4A分⼦流における,
14
2
continuum
iCOMs line
emission, exactly
the opposite
Ntot [10cm ] but lacks
1.3(0.5)
0.6(0.4)
0.9(0.6)
 (0.25-0.5)
0.7(0.3)
CH3 CHO[CH
of 4A2et 13(7)al. 2017).
Oneofthe possible
ex3OH]/[CH
3CHO]はTrot[K] (e.g. López-Sepulcre
9(2)23(19)
10-30(c)8(1)
142planationis thesmallerhot corino
which
Ntot [10cm ]for thissituation
0.5
 0.7
1.6(0.7)
1.0(0.4)
3
他のclass
0 size,hot corinos
CH3 OCH3(c)
could
younger age ofand this19
agrees with the
Trot[K]also imply a11
164A1,とも異なる.
10-30Fig.
9
7: Abundance
ratios between CH3 OH and CH3 CHO (Bot↗
142younger
outflow too. 0.02
Ntot [10cm age] of its
 0.02
 0.020.03(0.02)
tom panel), –CH3 OH and CH3 CHO column density (Upper
NH2 CHO(c)
In summary,theabundance ratio
3 OH/CH3 CHO 19
Trot[K]
11di↵erent CH16
10-30panel)–compared
to di↵erent sources for which the emitting size
⇨ IRAS 化学的性質の差(d)measured in the 4A1 and 4A2 outflows is unlikely caused by a has been estimated via interferometric observations: the values
CH3 OH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
themore
extended
4A2
outflowshowsnosignificant
variation
サイズ差による, 密度差 B1 (Codella et al. 2019), the Class I source SVS 13A (BianchiaRegion where formamide and dimethyl ether emits (Ceccarelli et al. 2017);
of thisratio
over a scale observations;of about 6000 au. On the contrary, the et al. 2019), and the Class 0 sources, in decreasing order of bolob
From Codella et al. (2019)based
on interferometricに起因か？
cobserved
CH
OH/CH
CHO
abundance
3
3
Fixed rotational temperature used to derive a range of possible Ntot ; ratio is consistent with metric luminosity, Barnard1b-S (Marcelino et al. 2018), HH212d
the 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, Stefetaldehyde is synthesized in the gas phase. The major reaction fen K. et al. 2019), IRAS 16293-2422B (Jørgensen et al. 2016),
is that between atomic oxygen and ethyl radical. The gas-phase CepE-mm (Ospina-Zamudio et al. 2018). The outflow values are
Model description
cloudwith a given
time dependent
profile. Additionally,
synthesis hypothesis also agrees withtheoreticalquantumchem- physical
shown
with
redgrains,(pink multifor CH3 CHO) markers, the hot corinos in
the new code allows a distribution of size for theistry
studies(Enrique-Romero
et
al.
2016,
2019).
Thus,
although
NOBLE+ is a gas–grain model simulating the chemical layer formation of the grain ice mantle,
blue growth(cyan forusing diamonds for the outflows, dots
3 CHO),of
andCH
depletion
terrestrial
show
that
acetaldehydecanbe
ion of gas and ices. It is the
upgradedlaboratory
version ofexperiments
GRAIN- thefor Class 0 and star for the Class I source. The cyan band repreice, and desorption.
formedon (2012a);the surfacesof dust grains (e.g Bennett et al. 2005a,b; sents the area in which the the hot corinos values fall.
E, initially developed by Taquet
et al.
in particular
In this work, we used a chemical network of 522 species ande-coded and improved in termsof computational
efficiency
Öberg
et al. 2009), ourresults provide evidence that the gas
4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？

A&A proofs: manuscript no. C-fractionation-final-eps[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).

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.

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

A&A proofs: manuscript no. C-fractionation-final-eps

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.

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

a suppression
the low-frequency
emissionby theRazin-Tsytovich eff
Probing the physicalor
conditions
and star offormation
processes in the
Galactic HII
regionS305
Accepted by The Astrophysical Journal

L. K. Dewangan1 , Saurabh Sharma2 , Rakesh Pandey2 , S. del Palacio3 , D. K. Ojha4 , P. Benaglia3 , T.
Baug5 and S. R. Das6

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 Fundamental Research, Homi Bhabha Road, Mumbai
400 005, India.; 5 Kavli Institute for Astronomy and Astrophysics, Peking University, 5 Yiheyuan Road, Haidian
District, Beijing 100871, P. R. China.; 6 Indian Institute of Space Science and Technology, Trivandrum 695547, India.

1

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

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

12,3Frantisek
DinnbierandPavel
KroupaWe present multi-scale and multi-wavelength observations of the Galactic H ii region S305, which is excited by massive

O8.5V and O9.5V stars. Infrared
images reveal an extended sphere-like shell (extension ∼7.5 pc; at Td = 17.5–
127 K) enclosing the S305 H ii region (size ∼5.5 pc; age ∼1.7 Myr). The extended structure observed in the Herscheltemperature map indicates that the molecular environment of S305 is heated by the massive O-type stars. Regularly
spaced molecular condensations and dust clumps are investigated toward the edges of the infrared shell, where the
PAH and H2 emission is also observed. The molecular line data show a signature of an expanding shell of molecular gas
in S305. GMRT 610 and 1280 MHz continuum maps reveal overdensities of the ionized emission distributed around
two O-type stars, which are surrounded by the horseshoe envelope (extension ∼2.3 pc). A molecular gas deficientregion/cavity is identified toward the center of the horseshoe envelope, which is well traced with PAH, H2 , molecular,
and dust emission. The edges of the infrared shell are found to be located in the front of the horseshoe envelope. All
these outcomes provide the observational evidence of the feedback of O-type stars in S305. Moreover, non-thermal

I.Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, D-509
Strahlen- und Kernphysik, University of Bonn, Nussallee 14-16, 53115 Bon
Faculty of Mathematics and Physics, Astronomical Institute, V Holesovic
E-mail contact: dinnbier at ph1.uni-koeln.de

Star clusters form out of the densest parts of infrared dark clouds. T
residual gas, which has not formed stars yet. Gas expulsion lowers the gra
unbinding many of11the cluster stars. These stars then move on their ow
field of the Galaxy, forming a tidal tail. We investigate the formation
to expulsion of primordial gas under various scenarios of gas expulsion t
dynamically evolved (age >galactic
T0yr)starclusters

L. K. Dewangan et al.

【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-bandoptical 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 cool
o
3
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– 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
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.
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

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