星形成ゼミ
2020/01/24
SFN 324 #1-#10

長谷川哲夫（国立天文台）

1

324 The dry and carbon poor inner disk of TW Hya: evidence for a massive icy dust trap
D. Bosman1 and Andrea BanzaI2#7 Arthur
2019A&A...632L..10B (2019/12)

E-mail contact: arbos at umich.edu

Gas giants accrete their envelopes from the gas and dust of proto-planetary disks, so it is important to determine thecomposition of the inner few AU, where most giant planets are expected to form. We aim to constrain the elemental
carbon and oxygen abundance in the inner disk (R < 2.3 AU) of TW Hya and compare with the outer disk (R > 2.3
AU) where carbon and oxygen appear underabundant by a factor of ∼50. Archival infrared observations of TW
Hya are compared with a detailed thermo-chemical model, DALI. The inner disk gas mass and elemental C and O
abundances are varied to fit the infrared CO, H2 and H2 O line fluxes. Best fitting models have an inner disk that has
a gas mass of 2 × 10−4 M⊙ with C/H ≈ 3 × 10−6 and O/H ≈ 6 × 10−6 . The elemental oxygen and carbon abundancesof the inner disk are ∼50 times underabundant compared to the ISM and are consistent with those found in the outerdisk. The uniformly low volatile abundances imply that the inner disk is not enriched by ices on drifting bodies that
evaporate. This indicates that drifting grains are stopped in a dust trap outside the water ice line. Such a dust trap
would also form a cavity as seen in high resolution sub-millimeter continuum observations. If CO is the major carbon
carrier in the ices, dust needs to be trapped eﬃciently outside the CO ice line of ∼20 AU. This would imply that theshallow sub-millimeter rings in the TW Hya disk outside of 20 AU correspond to very eﬃcient dust traps. The more
likely scenario is that more than 98% of the CO has been converted into less volatile species, e.g. CO2 and CH3 OH.
A giant planet forming in the inner disk would be accreting gas with low carbon and oxygen abundances as well asvery little icy dust, potentially leading to a planet atmosphere with strongly substellar C/H and O/H ratios.
Accepted by A&A Letters
http://arxiv.org/pdf/1911.11152

Jupiter formed as a pebble pile around the N2 ice line
A.D. Bosman1 , A.J. Cridland1 , and Y. Miguel1
1

Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands

E-mail contact: arbos at umich.edu
The region around the H2 O ice line, due to its higher surface density, seems to be the ideal location to form planets.
The core of Jupiter, as well as the cores of close in gas giants are thus thought to form in this region of the2 disk.
Actually constraining the formation location of individual planets has proven to be diﬃcult, however. We aim to use

Fig. 4. Schematic of the TW Hya disk showing the locations that should
trap the oxygen- and carbon-bearing molecules. Oxygen needs to be
trapped outside of 2.4 AU and is most likely trapped in the dust ring atthat location. Carbon can either be trapped at the same location, with
CO2 being the most probable carrier, or at larger radii outside the CO
ice line, with CO being the most probable carrier.

Lacy, J. H., Sneden, C., Kim, H., & Ja↵e, D. T. 2017, ApJ, 838, 66
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Miotello, A., vanC/H,
Dishoeck,E. F., Williams, J. P., et al. 2017, A&A, 599, A
Najita, J. R., Carr,
J.
S.,
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A Guide to NumPy (USA: Trelgol Publishing)
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In summary, we find that the elemental carbon and oxygen Salyk, C., Pontoppidan, K. M., Blake, G. A., Najita, J. R., & Carr, J. S.
• Outer disk: C/HやO/Hはabundances in the inner disk are lower by a factor of approxiApJ, 731, 130
Tak, F. F. S., van Dishoeck, E. F., & Black, J. H.
mately 50 compared to the ISM. Even at temperatures of 500 K, Schöier, F. L., van derunder-abundant（ISMのA&A, 432, 369
the gaseous carbon or oxygen elemental abundances cannot have
1/50）
K. R., Bergin,
E. A., Cleeves, L. I., et al. 2016, ApJ, 823, 91
increased by a factor of two, strongly constraining the release of Schwarz,
Schwarz, K. R., •Bergin,
E. A.,disk
Cleeves,L. I., etau)ではどう
al. 2018, ApJ, 856, 85
Inner
(<2.4
volatiles and grain destruction up to 500 K. This is interpreted Song, L., Balakrishnan, N., Walker,
K. M., et al. 2015, ApJ, 813, 96
as the dust trap responsible for the dust-free cavity also trapping Trapman, L., Miotello,A., Kama, M., van Dishoeck, E. F., & Bruderer, S.
か?
A&A, 605, A69
the major carbon- and oxygen-bearing ices outside of 2.4 AU. A
Methods
planet currently accreting gas in the gap will accrete very low Virtanen, P., Gommers, R., Oliphant, T. E., et al. 2019, ArXiv e[arXiv:1907.10121]
amounts of carbon and oxygen, while possibly accreting ISM Walker, K. M., Song,• DALI
disk
modelによる、近L., Yang,
B. H.,
et al. 2015, ApJ, 811, 27
concentrations of nitrogen and noble gasses. Depending on the Walsh, C., Nomura, 赤外ー中間赤外のスペクト
H., & van Dishoeck, E. 2015, A&A, 582, A88
accretion history this planet could have a substellar C/H and O/H Wolniewicz, L., Simbotin, I., & Dalgarno, A. 1998, ApJS, 115, 293
Yang, B., Stancil, P. ル線強度を予想
C., Balakrishnan, N., & Forrey, R. C. 2010, ApJ, 718,
abundance.
model
Zhang,
K., Pontoppidan, K. M., Salyk, C., & Blake, G. A. 2013, ApJ, 766,
Fig. 1. Surface density structure in inner regions of the TW Hya model. Fig. 2. Map of the gas temperature in the inner region of the• E.観測データ（VLT,
Zhang,A., Blake, G. A., Cleeves,Spitzer）とL. I., & Schwarz, K. R.
together with the emitting areas of the H2 S(1) line (black) the
CO K.,
v1 Bergin,
gas is the inner disk drop in gas surface density. The value gas = 0.1
Nat.
Astron.,1,
0130
vibrational
lines(orange)andthestrongest
line
of
the
H
O
33
µm
feaの比較から、innder
diskの2
used here best fits the H2 observations. The red curves show the column
Acknowledgements. Astrochemistry in Leiden is supported by the Netherlands(purple).
The
green
line
shows
T
=
150
K,
the
approximate
locadust
averaged oxygen and carbon depletion factors in TW Hya. The red Researchsolid ture
School for Astronomy (NOVA). This work is partly based on observagas mass, C/H, O/Hを決定
ofCRIRES
the H2 Ooniceline.
The emittingareas Observatory
radially overlap
the innerline shows a model with constant depletion. The dotted line showstions
themadetion
with
ESO
telescopes
at the Paranal
under in Appendix
A:
DALI
model
disk.
632,
L10 (2019)
program
ID
179.C-0151. This work is based in part on observations made with
depletion profile assuming that carbon and oxygen returnA&A
to theISM
theSpitzerSpace
Telescope,
whichisoperatedbytheJet
Propulsion
Laboratory,values above T gas = 150 K.
California Institute of Technology under a contract with NASA. This project has
Table 1. H2 , CO, and H2 O fluxes from observations and modeling. made use of the SciPy stack (Virtanen et al. 2019), including NumPy (Oliphant Table A.1. Parameters of the TW Hya model.
Both the CO lines and H2 O lines fit well to an inner disk
2006) andelemental
Matplotlib (Hunter2007). similar to the abundance found in the outerabundance

abundanceMolecular
structures and the Transition
CO v1 P(10)(1) line flux and the full(2)(2)
disk, Observed
which is flux
a factor50
lower
to the ISM. Even a
Stellar parameters
Wavelength (µm)
Modelfluxcompared
Eup (K)H2 O spectrum between 12 and 34 µm is extracted.
jump
of
a
factor
of
two
in
the
elemental
carbonoroxygenabunReferences
Stellar mass
0.74 MH2
J = 3 in1local(S (1))thermodynamic 17.0
1.57 ± 0.05
1.7
1015
The excitationfor H2 is done
equi- dance above
500
K can be ruledout based on
the observed fluxes. Stellar luminosity
1L
H2 as there are noJ collisional= 4 2 (S (2))
12.3
1.21
±
0.20
0.75
1681
Agúndez, M., Roue↵,
E., LePetit, F., & Le Bourlot,
J. 2018, A&A,
616, A19
librium (LTE)rate coefficients availThe
HWilner,
fluxesin
TableA.1M.,
show
that
this
model
underpredicts the X-ray luminosity
30
2O
CO
v,
J
=
1,
10
0,
11
(v1
P(10))
4.75
0.64
±
0.05
0.72
3330
10
erg s 1
Andrews,
S.
M.,
D.
J.,
Hughes,
et
al.
2012,
ApJ,
744,
162
able for H2 ; however, the low Einstein A coefficients of the H O detections between 20 and 31 µm by a factor of about two,
Andrews,
S.
M.,
Wilner,
D.
J.,
Zhu,
Z.,
et
al.
2016,
ApJ,
820,
L40
2
<0.17
0.03
3243
Disk parameters
2 O that deviations12from
5,8 –11LTE
2,9
H2 lines H
mean
are expected 17.12
toBanzatti,
be A.,
Meyer,
R.,
Bruderer,S., etgas
al. 2012,
ApJ, 745, 90in the model being too
which
isM.
in<0.29
linewith thetemperature
H
O
11
–10
17.22
0.05
2473
Disk
mass
0.025 M
23,90,10
negligible (Wolniewicz et al. 1998). For H2 O and CO the local
Banzatti, A.,
Pontoppidan, K. M., Salyk, C., et al. 2017, ApJ, 834, 152
low.
H2 O
112,9 –101,10
17.36
<0.32
0.11
2396
Criticalradius(R)
35 AU
c
excitation–de-excitation balance is calculated explicitly. For Bergin,
CO, E. A., Cleeves, L. I., Gorti, U., et al. 2013, Nature, 493, 644
Surface density slope ( )1H2 O
92,7 –81,8
21.85
0.2
Booth, R. A., Clarke, 2.8
C. J.,±Madhusudhan,
N., &6.7
Ilee, J. D. 2017,1730
MNRAS, 469,
collision rate coefficients from Yang et al. (2010) for H2 and3994
Scale height at Rc (hc )0.1 radH2 O
94,5 –83,628.23
2.1 ± 0.1
1.3
1929
Song et al. (2015) and Walker et9 al.–8(2015) for H are used Bosman,(see A.
4.D.,
Discussion
Bruderer, S., & van Dishoeck, E. F. 2017, A&A, 2122
601, A36
Flaring angle ( )0.3
5,4 4,5
Bosman,A. G. G. M., & van Dishoeck, E. F. 2018a, A&A, 611,
also Bosman
H2–7
O, the data file fromthe A. D., Tielens,Inner radius
0.05 AU
H2 O et al.1 2019). For 86,3
28.43
1.6
±
0.2
1.2
2031
5,2
A80 4.1. Constraining the inner disk chemical structure
LAMDA database (Schöier et al.
Gap inner radius
0.3 AU86,22005)–75,3 is used.
2031
Bosman, A. D., Walsh, C., & van Dishoeck, E. F. 2018b, A&A, 618,
A182
Bosman, A.
D., Banzatti,
Bruderer,S., et al. 2019,
A&A, and631,2006
A133
2.4 AU
Here,
using
a±morecomplete
physicalchemical structure of Gap outer radius
H2 O
77,0 –66,1
28.6
1.7 A.,
0.1
1.2
Bruderer, both
S. 2013,
A&A,
559,and
A46 the outer disk, we can2006
100
the
inner
quantify the total H2 Inner disk gas-to-dust
77,1 –66,0
Bruderer, S., van Dishoeck, E. F., Doty, S. D., & Herczeg, G. J. 2012, A&A, 541,
5
Inner
disk
gas
depletion
[10
–1]
H2 O
63,1 –50,5
30.87
2.7
±
0.2
1.8
934
mass,
as
well
as
the
volatile
carbonandoxygenabundancein
3. Results
A91
Small
dust
size
0.005–1µm
85,4 –74,3
1806
inner disk,
confirmingthat
the inner
disk
of TW Hya is both
Bruderer, theS., Harsono,D., & van
Dishoeck, E.
F. 2015,
A&A, 575,
A94
Figure 2 compares
the emitting 6regionsofthedi↵erent
species
Cridland,A.
J.,
Pudritz,
R.
E.,
Birnstiel,T.,
Cleeves,L.
I.,&
Bergin,
E.
A.
2017,
Small
dust
fraction
0.01
H2 O
–5
33
3.96
±
0.46
4.0
1504
oxygen- and carbon-poor by a factor about 50 compared to the6,1 5,0469, 3910
in the constant abundance modela ISM.
0.005–1000 µm
75,2with–64,3 gas = 0.1. There isMNRAS,
1524there is no signifi- Large dust size
Furthermore, our modeling shows thatDawson,R.
I., & Johnson, J. A. 2018, ARA&A, 56, 175
large overlap in the emitting areas, especially in the inner disk cantLarge dust fraction
0.99(factor2
ormore)increaseinvolatile
carbonoroxygenin
Donaldson,
J.
K.,
Weinberger,
A.
J.,
Gagné,
J.,
et
al.
2016,
ApJ,
833,
95
Notes.
CO hasline flux
is takenfrom Banzatti
et al.area(2017),
H2 and H2 O fluxes are extracted from the Spitzer-IRS spectra using the
Large
dust
settling
factor
0.2(<2.4 Observed
AU). Water
the most
confinedemitting
andandonly
Du, F., Bergin,
E. A., Hogerheijde,M., there
et al. 2017,
ApJ,sign
842, of98 volatile release at thethedominant
inner
disk.
Thus,
is no
methodBanzattial. (2012).
The andtableHdenotes
the upper level energy of thetransitionsof each blend
accordingto our model. The
3probesinthe
inner etdisk
while CO
2 both also probe the outer
CO
or
H
O
ice
lines
nor
is
there
evidenceofcarbonaceousor
2
2 by taking the average flux of two adjacent OH lines.
H2 S(2) line is contaminated by an OH line; the contribution of the OH line was estimated
disk,
where
the
composition
of
the
gas
is
alreadystronglycon(1)
14
1
In the case of H2 O, the dominant transition(s) of the feature. (2) In units of 10silicate
erg s grain
cm 2 .destruction at T < 500 K.

Results• Figure 2 – emiIng regions
H2O probes only the inner disk
CO and H2 probe both inner and outer• Figure 3 – comparison with observa]ons
H2 ﬂuxes constrain inner disk gas mass
(obs show higher H2 S(2)/S(1) line ra]ocompared with the models)
CO and H2O ﬁt well with C/H, O/H similar
to those in the outer disk (~1/50 ISM),
Fig. 3. Comparison of the H2 line fluxes (left), CO rovibrational line flux (middle), and the H2 O 33 µm feature flux (right) between models andeven ruling out their x2 jump at >500 K
data. Left panel: the amount of gas within 2.4 AU is varied. Middle and right panels: gas = 0.1 is used and C/H and O/H are varied respectively.
Horizontal bands show the 1 variation of the observed fluxes. The
di↵erent
colouredpointsdenotedi↵erent
valuesforT.
The
temperature
step The dry andA. D. Bosman and A. Banzatti:
carbon poor inner disk of TW Hydrae
Discussion
threshold above which the abundances are varied. The vertical lines in the middle and right panel show the volatile carbon and oxygen abundances•
We ﬁnd – the inner disk of TW Hya is
assumed for the ISM (Meyer et al. 1998; Lacy et al. 2017).
both O- and C-poor by a factor 50 rela]ve
lower oxygen abundances in the inner disk; however, it would dust grains with almost no ices, or volatiles are efficiently locked
Eistrup,to ISM.C., Walsh, C., & van Dishoeck, E. F.
in iceson solidsthat are not transported through the disk.
also move the H2 O emission to colder gas, increasing thedis- CO2
H2O,
and
CH3OH
Inner diskgap:
No signvola]le releaseat CO2 orFavre,C., ofCleeves,L. I., Bergin,
E.H2O
A., Qi, C
To deplete the entire disk inOuter
volatiles, diska periodof very strong
crepancy between model and observations
for the22 and 28 µm
surface:features. A constant-abundance model therefore fits the data bet- snowlines
radial drift coupled with strong radial mixing is necessary (e.g.,ice
low carbon, oxygen
L38lines, no evidence of carbonaceous or
low thecarbonter than a ring model.
Booth et al. 2017). In such a scenario,
icy grainsand
drift fromsilicategrain
at >500ApJ,
K. 776, L28
themassreservoir
in
the
outer
disk
into
the
regionsof
thedisk
Gibb, E. L.,& destruc]on
Horne, D. 2013,and dust abundance
oxygenabundance
where the ices desorb. This leads
to enhancements
in C/H and4.2. Hiding C and O carriers?
• Hiding
and O carriers?
unlikely.J., & Pascuc
Gorti,
U.,CHollenbach,D.,– Najita,
O/H in the inner regions of the disk. After a few million years
The DALI models predict that CO and H2 O are the dominant all of this high-C/H
CO snowline
CO2/H2<
1e-9
asstringentand high-O/H gas is accreted onto the star
Hogerheijde, M. R., Bergin,upper
E. A.,limit.
Brinch, C.
gas-phase oxygen and carbon carriers in the inner disk. However, and the disk is left depleted in carbon and oxygen. However, a
C2H2
and
HCN
even
less
than
CO2.
it is possible that carbon and oxygen are locked in other gaseous disk like this will also be strongly depleted in solid material as
Hunter, J. D. 2007, Comput. Sci. Eng., 9, 90
species. There are a few obvious candidates for hiding more car- the grains that transport the ices inward will continue to drift into
CH4 abundance
not stronglyP.,
constrained
60
AU
20
AU
Kaeufl,H. U., Ballester,
Biereichel, P
bon and oxygen in molecular gas: CO2 , C2 H2 , HCN, and CH4 . the star leading to dust depletions at least as high as the volatile
from
obs,
but
not
expectedtobe theThere is a CO2 feature detected in the Spitzer spectrum of TW element depletion. This scenario is therefore very unlikely for
Instrumentation for Astronomy, eds. A. F
Outer
dust ringHya. Applying the model results from Bosman et al. (2017) to TW Hya, which has a massive
dust component and a gas-to-dust
most abundant C carrier from chemical
the detected feature retrieves a CO2 abundance lower than 10 9 ratio of around 100 (Bergin ettrapping
SPIE, 5492, 1218
CO
al. 2013).
2.4 AU dust ring trapping
models.
with respect to H2 . The models in Bosman et al. (2017) do not
As efficient transport is excluded, this leaves 98% of the carKama,
M., Bruderer,S., van
Dishoeck, E. F., ehave a gap, which if included would only increase thestrengthof andrichthatgrains?
H2O,
CO2
CH3OH
bon andoxygen locked in solids
are not efficiently trans• Implica]onsof uniform
deple]onthe CO2 lines. As such the CO2 abundance <10 9 is a stringent ported. Assuming that CO and H2 O are the dominant oxygen and
Kennedy,G.
M.,&
Kenyon,S. locked
J. 2008,
Inner
dust
beltcarrier of rich=> Vola]les must be eﬃciently
in ApJ, 6
upper limit and this molecule
is not anabundant
either grains
carbon carriers in the outer disk, it is necessary to stop CO from
Krijt,
F. J.,
Bergin,E. A. 2016, A
carbon or oxygen.
being transported over the CO ice line by a dust trap at a locaicesS.,
onCiesla,
solids thatare&nottransported
C2 H2 and HCN are detected in many proto-planetary disks tion larger than where the CO ice line is located. For TW Hya
Krijt,
S., Schwarz,
throughthe disk. K. R., Bergin, E. A., & Cie(Salyk et al. 2011), however neither are detected in the spec- this would imply that one of the shallow millimeter continuum
4. SchematictheandTW
diskshowingthelocationsthatshouldtrum Fig.
of TW Hya.
As the Q-branchesof
of HCNC2 HHyaaround2
Lacy,
J. isH.,C., Kim,H., & Ja↵e,rings of TW Hya outside of 20 AU corresponds to an efficient
If CO
theSneden,
main carrier,
it is necessary
to D. T
14 µmtrap
have similar
upperlevel energies
andcarbon-bearing
Einstein A coef- dust trap.
An efficient dust Oxygen
trap at >20 AU needs
should resultin abedisk
theoxygenandmolecules.
toMenu,
Henning,
et al. 2
stopJ.,
COvan
by aBoekel,
dust trapR.,near
CO snowT.,
line.
ficients to the 15 µm Q-branch of CO2 , both HCN and C2 H2 with a large cavity. As dust is abundant down to 2.4 AU, a secshouldhave been detected
if theyofare 2.4
as abundantas
CO2 .isThemosttrappedoutsideAU
andlikelytrapped
in
dust
ring
at
ond dust
trap would
be necessary
atthethat location,
which
would
Meyer,
D.
M.,
Jura,
M.,
&
Cardelli,
J.
A.
1998
If CO is eﬃciently converted to lesslack of observed features implies that both HCN and C2 H2 trap H2 O-rich grains.
vola]le A.,
CO2vanandDishoeck,
CH3OH, dustisE.trapF., Williams,
J
thatlocation.
CarboneitheratHthesame location, with Miotello,containless than
1% of the volatilecarbon.can
The final
possiblebe trapped
In this scenario
2 O would be far more efficiently locked ingaseous carbon carrier is CH4 . Observations of this molecule large grains than CO as the former is frozen out in a larger fracneeded
near
theirJ.snowlines (close
to et al. 20
J. R.,
Carr,
S., Strom,
S. E.,
CO
being
the most
probableat larger radii outside the CO Najita,
have sofar 2
only
been successful
in one disk,
in which CH4 carrier,lines tion ofor
the disk. However, if gaseous CO is efficiently convertedH2O
snowline).
have been detected in absorption (Gibb & Horne 2013). The into less volatile species, especially CO2 and CH3 OH, then theÖberg, K. I., Boogert, A. C. A., Pontoppidan,4
ice line, with CO being the most probable carrier.
CH4 abundance is therefore not strongly constrained by observations. However, from chemical models CH4 is not expected to

CO- and H2 O-depletion fractions are likely to be more similar
and an efficient dust trap around 20 AU is no longer strictly nec-

Oliphant, T. 2006, NumPy: A Guide to NumP

Jupiter formed as a pebble pile around the N2 ice line
1
1
1
A.D.
A.J. Cridland, and Y.
Miguel324 Bosman
Jupiter, formed
as a pebble
pilearound the N ice line

2

Bosman1, A.J.
Cridland1,
and Y. Miguel1
Leiden A.D.
Observatory,
LeidenUniversity,
PO Box 9513, 2300 RA Leiden, The Netherlands#8

1

2019A&A...632L..11B (2019/12)

E-mail contact: arbos at umich.edu
The region around the H2 O ice line, due to its higher surface density, seems to be the ideal location to form planets.
The core of Jupiter, as well as the cores of close in gas giants are thus thought to form in this region of the disk.
Actually constraining the formation location of individual planets has proven to be diﬃcult, however. We aim to use
the Nitrogen abundance in Jupiter, which is around 4 times solar, in combination with Juno constraints on the total
mass of heavy elements in Jupiter, to narrow down its formation scenario. Diﬀerent pathways of enrichment of Jupiter’s
atmosphere, such as the accretion of enriched gas, pebbles or planetesimals are considered and their implications forthe oxygen abundance of Jupiter is discussed. The super solar Nitrogen abundance in Jupiter necessitates the accretionof extra N2 from the proto-solar nebula. The only location of the disk that this can happen is outside, or just inside
the N2 ice line. These constraints favor a pebble accretion origin of Jupiter, both from the composition as well as froma planet formation perspective. We predict that Jupiter’s oxygen abundance is between 3.6 and 4.5 times solar.
Accepted by A&A
http://arxiv.org/pdf/1911.11154

VLBI observations of the G25.65+1.05 water maser superburst
Ross A. Burns1,2,3 , Gabor Orosz4,5 , Olga Bayandina1,6 , Gabrielle Surcis7 , Mateusz Olech8 , Gordon
MacLeod9,10 , Alexandr Volvach6,11 , Gerogij Rudnitskii12 , Tomoya Hirota2 , Katharnia Immer1 , Jay
Blanchard1,13 , Benito Marcote1 , Huib van Langevelde1,14 , James O. Chibueze15,16 , Koichiro Sugiyama2,17 ,Kee-Tae Kim3,18 , Irina Valtts6 , Nadya Shakhvorostova6,19 , Busaba Kramer17,20 , Willem A. Baan5,21 ,Crystal Brogan22 , Todd Hunter22 , Stan Kurtz23 , Andrey M. Sobolev19 , Jan Brand24 and Larisa Volvach6,11
1

Joint Institute for VLBI ERIC, Oude Hoogeveensedijk 4, 7991

5

Table 1. Elemental abundances relative to H.
Element

Protosolar

Jupiter

Enhancement

Three theories of gas giant forma]on in the Solar
SystemC
2.95 ⇥ 10 4
1.19 ± 0.29 ⇥ 10 3
4.02 ± 0.98
• Core accre]on – km-sized planetesimals
N
7.41 ⇥ 10 53.32 ± 1.27 ⇥ 10 44.48 ± 1.71
diﬃculty in ]mescale => forma]oninO
5.37small⇥ 10 4 radii
2.45 ± 0.80 ⇥ 10 4 (⇤) 0.46 ± 0.15 (⇤)
H2O ice line at a few au asNotes.
a preferredloca]onfrom
of Jupiter
Proto-solar abundances
Asplund etforma]onal. (2009), Jupiter abun(⇤)
dancesfrom
Atreyaetal.
(2016).
Oxygenmeasurement in a hot spot;000.9336245134.7849-168.1312cmBT8.9664008.966(ya)qTf(()TjETQq0.933TQHcmB12cmBT8• Pebble accre]on – millimeter- and cen]meter-sized pebbles
planetary core needs to form at large radii, outside 15 au, to end
up at a few au when the gas disk dissipates• Gravita]onal instability
cold outer regions
Elemental abundances• Table 1 – from Galileo mission, N enhancement!
• N in ISM is extremely vola]le (N2, 20 K)=> poten]ally a powerful probe of forma]on loca]on of planets
N-enriching of Jupiter• Figure 1 – three ways to enrich the atmosphere of a gas giant witha speciﬁc element• A) If Jupiter’s atmospheric enhancements are due to the accre]onof enriched gas, it must have accreted most of its mass just within
the N2 ice line => unlikely• B) C) Assume that Jupiter accreted a solar N/H ra]o from the gas,
and that all of the extra N comes in solids deposi]ng their full N
reservoir into the atmosphere.
=> the mass of refractories (silicates and metals) that Jupiter needs
to accrete as a func]on of the nitrogen-to-refractory mass ra]o forthe accre]ng bodies (Figure 2)
A&A 632, L11 (2019)

Table 1. Elemental abundances relative to H.
Element
C
N
O

Protosolar
42.95 ⇥ 10
7.41 ⇥ 10 55.37 ⇥ 10 4

Jupiter

Enhancement3

1.19 ± 0.29 ⇥ 10
3.32 ± 1.27 ⇥ 10 42.45 ± 0.80 ⇥ 10 4 (⇤)

4.02 ± 0.98
4.48 ± 1.71
0.46 ± 0.15 (⇤)

Notes. Proto-solar abundances from Asplund et al. (2009), Jupiter abundances from Atreya et al. (2016). (⇤) Oxygen measurement in a hot spot;
this probably does not represent bulk oxygen abundance of the atmosphere.

6

Juno mission

A. D. Bosman et al.: Jupiter formed as a pebble pile around the N2 ice line

Implica]ons

Fig. 2. Nitrogen-to-refractory mass ratio ofenriching solids necessary to reach Jupiter’s Nitrogen content as a function of total refractory massadded to Jupiter. It is assumed that Jupiter has
accreted solar composition gas and that the excess
nitrogen was brought in frozen on solids. The
upper limit to the total heavy element mass is taken
to be 27 M (Wahl et al. 2017). This can be in theform of ice-poor or ice-rich bodies; for ice-poorbodies the refractory mass is assumed to be thetotal mass of heavy elements, for ice-rich bodies,assuming H2 O and CO are frozen out, as would
be expected for a very N2 -rich body, the heavy element mass is around two times the refractory mass,meaning that only ⇠12 M of refractories can beaccreted. The nitrogen-to-refractory mass ratios of
ISM grains without N2 ice (Boogert et al. 2015),
comets (Altwegg et al. 2019), or CI chondrites(Lodders et al. 2009) have been added for comparison. None of these have a high-enough nitrogen
fraction to enhance Jupiter’s atmosphere.

Table 2.etCarbonoxygenandabundances
solar,
predicted
Bisschop,E., Fuchs,
G. W., van of
Dishoeck,E. F., & Linnartz,
H. 2007,
A&A,
Berginal. and(2015)
placerelative
25%toofthetotalforcarbon
inS.•theenrichingsolids,werichneedmajority of the N2 to
HighamountN/H in Jupiter– accre]onof N2
gastheor solids
474, 1061
Jupiter’s atmosphere assuming di↵erent contributing sources.
refractory phase. This leads to a gas-to-refractory massratio
of=> forma]onbeM.,in& theice,A.and
thus
temperatures
Bitsch,B., Lambrechts,
Johansen,2015,
A&A, 582,
A112
near
or
outsideN2
ice line below 20 K (Bisschop et al.
Bitsch,B.,
Izidoro,A.,
Johansen,
A.,
et
al.
2019,
A&A,
623,
A88
186 Incorporated
and a nitrogen-to-refractorymass ratio ofC/O
0.2, theBockelée-Morvan,e↵ective(20D.,–2007),of a smaller
fractionof N2 trappedin a water-richCalmonte,
Charnley, S., et al. 2015,
SpacearoundSci. Rev, solar
species[O/H]/[O/H]? [C/H]/[C/H]?
80 au insteadinU.,protoplanetarydisksmass stars)
upper limit to the amount of nitrogen that can be added
ice,
in
which
case
N
can
be
trapped
in
the
ice
up
to
temperatures
197,to47 the2• Hayfield,
Pebbleaccre]onseems
especially
Accretion of N2 enriched gas
Boley, A. C.,
T., Mayer,
L., & Durisen,
R. H.
2010, Icarus,promising
207, 509
solid1: phase.
disk wouldofK(LunineStevenson
1985;
Collings et al. 2004).
Gaseous N2Above
and CO this mass
1.8 ratio, the3.6 outer 1.1
Bolton, S.have
J., Adriani,A., 40Adumitroaie,
et al. &2017,821
Bitsch+19– it is V.,
possible
toScience,
form356,
a coldJupiter star]ng core growth as(⇤)
Boogert,C. A., Gerakines, P. A., & Whittet, D. C. B. 2015, ARA&A, 53, 541
refr.more
C and Henhanced
2.7 nitrogen4.0than
0.8 is seen
had 2:to1 +bein
what
inA. the2 O ice
50MNRAS,
au 487, 3998(⇤)
Booth, R. A., &far
Ilee,out
J. D. as2019,
2 + silicates
3.3 we find 4.0
solar3: photosphere,a scenario
unlikely.0.66
In the outer
Booth, R.parts
A., Clarke,
C. J., Madhusudhan,
N., & Ilee, J. D.
2017,
MNRAS, in469,refractories (0.05 M_sun ofrequiredpebblereservoir:
M_earth
Accretion of N2 rich pebbles
3. Implicationsof 75
Jupiter’s
nitrogenenrichment3994
of the
disk,
where
all
non-noble
elements
heavierthanhydro1: N2 , CO and H2 O ice
3.6
3.6
0.55
Bosman, A. D.,gas)
Tielens,A. G. G. theM., &N2
van iceline
Dishoeck, E. F. 2018, A&A, 611,
outsidegen 2:aresolids,the total gas-to-solid
ratio drops
A80and so
1 +inrefractorycarbon
3.6
4.5
0.7 to 77,
3.1.276,Enrichment
during formation=>Science,
proto
solar
Boss, A. P. 1997,
1836 nebula should be cold and among the largest and most
3: 2 + silicates
0.55 thethe total
solid mass in these4.5regions is 4.5
about twice
available
Boss, A. P. 2002,
Earth Planet.
Sci. Lett.,
202, 513 observed (late class I or early class II)
massivediskscurrently
highIcarus,
nitrogenCiesla, F. J., & Cuzzi,The
J. N. 2006,
181, 178 abundance in Jupiter necessitates the accretion
refractory
Notes. (⇤) Setmass.
to match Jupiter’s carbon abundance.
Diﬃculty
gravita]onal
instability
Cleeves, L. •I., Öberg,
K. I., Wilner,
D. J., et al. 2018, ApJ,
865, 155 scenario – hea]ng and mixing 7ofN inrichgas or solids.
Enrichment of Jupiter during its formaThe gravitational moments measured by Juno (Bolton
Collings,etM. al.
P., Anderson, M.2 A., Chen, R., et al. 2004, MNRAS, 354, 1133

Güdel , Yanina Metodieva
School AofSwis
Physics
and ofAstronomy,
Universityof Leicester,
University
Road, Leicester,LE1system
7RH, UK;
324
view
X-ray andUV radia]onin theplanet-forming
T-Tauri
PDSUniversity
70
of Vienna,
Dept.
ofAstrophysics,
Turkenschanzstr.
17,
1180
Vienna,Austria
R.G. Joyce1, John P. Pye1, Jonathan D. Nichols1, Kim L. Page1, Richard Alexander1, Manuel Güdel2, Yanina Metodieva2#1 Simon
2019MNRAS.tmpL.163J (2019/11)
1

2

E-mail contact: sj328 at leicester.ac.uk

PDS 70 is a ∼5 Myr old star with a gas and dust disc in which several proto-planets have been discovered. We present
the first UV detection of the system along with X-ray observations taken with the Neil Gehrels Swift Observatory
satellite. PDS 70 has an X-ray flux of 3.4 × 10−13 erg cm−2 s−1 in the 0.3–10.0 keV range, and UV flux (U band) of
3.5 × 10−13 erg cm−2 s−1 . At the distance of 113.4 pc determined from Gaia DR2 this gives luminosities of 5.2 × 1029
erg s−1 and 5.4 × 1029 erg s−1

8Hasmik Andreasyan1 , Tigran Magakian1 and Tigran Movsessian1

324 Simultaneous photometric and spectral analysis of a new outburst of V1686 Cyg
Byurakan
Observatory
NAS
Armenia,
Aragatsotn prov., 0213, Armenia
HasmikAndreasyan1,
TigranMagakian1Byurakan,
and Tigran Movsessian1#2
arXiv:1912.01262 (2019/12)

1

E-mail contact: hasmik.andreasyan at gmail.com

We present an analysis of the optical observations of Herbig AeBe star V1686 Cyg, which is associated with a small
isolated star-forming region around HAeBe star BD+40◦ 4124. We observed this star as a part of our project of young
eruptive stars investigation. Observations were held on 2.6m telescope of Byurakan Observatory from 2015 to 2017.
For this period we obtained V1686 Cyg direct images and 14 medium- and low-resolution spectra. In the course ofobservations we noticed that this star underwent a not-typical brightness outburst. After data reduction we foundthat the full rise and decline of V1686 Cyg brightness had almost 3 magnitudes amplitude and lasted about 3 months.
We were also able to trace the changes of the stellar spectrum during the outburst, which are correlated with thephotometric variations.
Accepted by Research in Astronomy and Astrophysics
http://arxiv.org/pdf/1912.01262

Modeling the accretion disk around the high-mass protostar GGD 27-MM1
Nacho Añez-López1,3 , Mayra Osorio2 , Gemma Busquet1,3 , Josep Miquel Girart1,3 , Enrique Macías4,5,6 ,Carlos Carrasco-González7 , Salvador Curiel8 , Robert Estalella9, Manuel Fernández-López10 , Roberto
Galván-Madrid7 , Jungmi Kwon11 and Jose María Torrelles1,2Institut de Ciències de l’Espai (ICE-CSIC), Carrer de Can Magans s/n 08193 Cerdanyola del Vallés, Barcelona; 2Instituto de Astrofísica de Andalucía, Glorieta de la Astronomía, s/n, 18008, Granada; 3 Institut d’Estudis Espacials
de Catalunya, Gran Capità, 2-4, Edifici Nexus, Desp. 201, 08034 Barcelona; 4 Department of Astonomy, Boston
University, 725 Commonwelth Avenue, Boston, MA 02215, EEUU; 5 Joint ALMA Observatory, Llano de Chanjnantor,
Desierto de Atacama, Chile; 6 European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei
München, Germany; 7 Instituto de Radioastronomía y Astrofísica, Antigua Carretera a Pátzcuaro # 8701, Ex-Hda.
159San José de la Huerta, 58341 Morelos, Mich., México; 8 Instituto de Astronomía de la Universidad Nacional Autónoma
deMéxico,Circuito Exterior,área de disk
la Investigación
Científica,CiudadUniversitaria,
México,
CDMX., C.P. 04510;
324
Modeling
the accre]onaround thehigh-mass
protostar
GGD
27-MM19Departamentde Física Quántica
i Astrofísica,
Institut Josepde Ciènciesdel Cosmos
i Franqués,
Nacho Añez-López1,3,
Mayra Osorio2,
Gemma Busquet1,3,Miquel Girart1,3,
Enrique(ICC),Martí
Macías4,5,6, Carlos
Carrasco- 1 08028#3
10Barcelona;
Instituto
Argentinode Radioastronomía(CCT-La Plata, CONICET;CICPBA),Jungmi
C.C. Kwon11
No. 5, 1894,
Villa
González7,
SalvadorCuriel8, Robert
Estalella9, Manuel Fernández-López10,
Roberto Galván-Madrid7,
and Jose
11
María Torrelles1,2
Elisa, Buenos
Aires, Argentina;
The University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo 113-0033, Japan
2020ApJ...888...41A (2020/01)

E-mail contact: nacho.anyez at gmail.com
Recent high-angular resolution (≃ 40 mas) ALMA observations at 1.14 mm resolve a compact (R ≃ 200 au) flattened
dust structure perpendicular to the HH 80–81 jet emanating from the GGD 27-MM1 high-mass protostar, making it
a robust candidate for a true accretion disk. The jet/disk system (HH 80–81/GGD 27-MM1) resembles those foundin association with low- and intermediate-mass protostars. We present radiative transfer models that fit the 1.14 mm
ALMA dust image of this disk which allow us to obtain its physical parameters and predict its density and temperature
structure. Our results indicate that this accretion disk is compact ( Rdisk ≃ 170 au) and massive (≃ 5 M⊙ ), about
20% of the stellar mass of ≃ 20 M⊙ . We estimate the total dynamical mass of the star-disk system from the molecularline emission finding a range between 21 and 30 M⊙ , which is consistent with our model. We fit the density andtemperature structures found by our model with power law functions. These results suggest that accretion disks
around massive stars are more massive and hotter than their low-mass siblings, but they still are quite stable. We also
compare the temperature distribution in the GGD 27–MM1 disk with that found in low- and intermediate-mass stars
and discuss possible implications on the water snow line. We have also carried out a study of the distance based on
Gaia DR2 data and the population of young stellar objects (YSOs) in this region, and from the extinction maps. We
conclude that the source distance is within 1.2 and 1.4 kpc, closer than what was derived in previous studies (1.7 kpc).
Accepted by Astrophysical Journal
https://arxiv.org/pdf/1911.12398.pdf

Uncovering a 260 pc wide, 35 Myr old filamentary relic of star formation
Giacomo Beccari1 , Henri M.J. Boﬃn1 , and Tereza Jerabkova1,2,3,4,5,6
European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München; 2 Helmholtz Institut
für Strahlen und Kernphysik, Universität Bonn, Nussallee 14–16, 53115 Bonn, Germany; 3 Astronomical Institute,Charles University in Prague, V Holešovičkách 2, CZ-180 00 Praha 8, Czech Republic; 4 Astronomical Institute, Czech
Academy of Sciences, Fričova 298, 25165, Ondřejov, Czech Republic; 5 Instituto de Astrofísica de Canarias, E-38205
La Laguna, Tenerife, Spain; 6 GRANTECAN, Cuesta de San Jose s/n, 38712 Brena Baja, La Palma, Spain 10
1

E-mail contact: gbeccari at eso.org

The Astrophysical Journal, 888:41 (15pp), 2020 January 1

The Astrophysical Journal, 888:41 (15pp), 2020 January 1 Añez-López et al.

Añez-López et al.

25 Me3and keep the total mass
Because of the similarities with disk–protostar–jet systems in mass values between 15 and Table
Model Parameters
the dynamical
mass.
low- and intermediate-mass protostars, in this paper we analyze (star + disk) close toBest-ﬁt
Mass accretion rate. Carrasco-González et al. (2012)
the GGD27–MM1 disk by applying models that have
Parameter
Value
successfully explained disks around low-mass stars. The main estimate the mass-loss rate in the jet using the formulation
given
byReynolds(1986;
see
Equation(2)), who model theﬁtted
goal is to investigate if the assumptions that are usually adopted
20
M*(Me)
emission from an ionized jet by adopting a power-law
for disks around low-mass stars can be roughly extrapolated Ttoeff free–free(K)
12,000ﬁtted
dependence with radius (see also Anglada et al. 2018):
the case of massive stars. For example, disks around low-mass
R* (Re)25
ﬁtted
stars are much less massive than the central protostar, and0.75
Distance
1.4 v
adopted⎤⎡⎡ (kpc) out ⎤
⎡
⎤
M
S
jet
n
-1
−5
therefore they are usually gravitationally stable. In the high⎥ adopted/reﬁneda
M (M⎢e yr−1) -1 ⎥ = 1.9 ´ 10-6x 07×10⎢⎣⎥⎢⎣ M: yr ⎦1000 km s-1 ⎦ ⎣ mJy ⎦mass case, it is not clear if disks are stable (Maud et al. 2019) M
or (M
)
5
calculated
disk
e
1.5
unstable (Motogi et al. 2019; Zapata et al. 2019).
⎡ n ⎤-0.45 ⎡168
D ⎤ ⎡ q0 ⎤0.75
Rdisk (au)adopted/reﬁneda
(2 )
.
´⎢
⎥
⎢
The paper layout is as follows. In Section 2 we present the⎣ GHz ⎦⎥H (au)
7 ⎦ ⎣⎢ rad ⎦⎥calculated⎣ kpc
ALMA observations of the disk around GGD27–MM1,10014
ﬁtted
Rin (au)
describing the disk model in Section 3. In Section 4 weaangle
present the main observational properties of the region. iIn(°)They assume a pure hydrogen jet49with a constant openingadopted/reﬁned−1θ∼19°(conicaljet),terminal
velocityv(∼1000
km
s
),
a
(μm)
500
ﬁtted
0
jet
max
Section 5 we explain the ﬁt procedure, and Sections 6 and 7
α ionization fraction x0=0.1,0.1and electron temperatureﬁtted
correspond to results and discussion, respectively. We list the4of the sky.
main conclusions in Section 8 and present the new distance Te=10 K, and that the jet axis is in the -planeTheyobtaina mass-loss rate of M out ~ 10 5 Meyr−1for aestimation in the appendix.
Note.
−6
−1

distance withof 1.7kpc,;8×10
Meandyr uncertainty.
for the corrected
Parameter
observational
constraints
distance of 1.4kpc (see the appendix). This value is in
2. ALMA Observations
agreement with the value obtained from CO observations of theoutﬂow associated with the jet (Qiu et al. 2019).
In this work, we use ALMA continuum observations inclination
at molecularangleof ∼49° (angle between the rotation axis andAssuming the accretion rate M acc of the disk onto the star is
1.14mm (263.0 GHz; project ALMA#2015.1.00480.S). The
the ∼10line timesof sight).
accretionraterate,
which inlargerThe
thanmass
the mass-loss(Bontemps
et oural. model
Band 6 receiver with the correlator set in continuum modeis 1996),a veryparameter,
resultedbe ∼7×the sensitive
mass accretion
rate wouldbe M accto∼8×(time division mode) covering the 253.0–257.0 and
−1
4
−1
MM
total luminosity∼1×10
Le, which
10−5
10−5
However,
Beltrán & deis Wit(2016, andeyreyr . . The
269.0–273.0 GHZ frequency ranges was used. The observareferences
therein)obtainbetweenestimation
the mass-loss(seerate andis inagreementwiththea ratio
previous
Section 4).
tions were carried out with 37 antennas in the c36-8/7
accretion
rateisof 20
approximately∼0.3together
for disks inyoung,
conﬁguration, which provided baselines between 82m andwithdisk mass
Themass
stellarmass
Me, whichhigh-mass
stars. In thiscase,theestimatedmass accretion
rate would
be for the
11.05km (13–5400 kλ). The Stokes I image toward GGD27)
isconsistentwiththedynamical
mass
(5 M
e
−5
−1
lower, ∼3×10
MeyrM. ; see Section 4).
MM1 was generated using the resulting visibilities after thestar–disk
system (21–30
eEven though the mass accretion
rate is not well determined
subtractionof the compact
source(seeaxisSection
2.1).
This
Figure5. Position–velocity
plots along
the majorof the disk
for theSO2 was Regarding the composition of the disk in terms of grain size,
using
these
methods,
itallowsus
todeﬁne a range of values to
using
the
CASA
task
tclean
with
a
value
of
0.5
for
the
9done
–8
and
19
–19
lines.
Contours
are
2,
4,
8,
16,
32,
64,
and
128
times
2,8 1,7
3,17
2,18
−1
sizes
grains we
accordingwith theTherefore, in
our ofmodeling,
explored valuesof results. The dashedblack line
the differenttherms noiseof the maps,
1.2 mJybeam
robustBriggsweightingparameter.
Becauseof shows
a lackof explore.maximum−5−4−1
expected Keplerian proﬁle for 25 Me. The red dashed line shows the best foundM accin inGirart
the ∼1×10
to ∼2×10
Meyrrange.
et al. (2018)
were tested(seeSection 4). We didvisibilities
between
150
and
300
kλ
and
in
order
to
ﬁlter
Keplerian ﬁt to the data using the method proposed by Seifried et al. (2016) at
Stellarparameters.differences
It is expected between
that most ofmodels
the dynamical
not ﬁndsubstantial
with amax ofextendedemissioncomingmassfromthe 21envelope,
we–81,7used
5σ.
The ﬁt corresponds
to a dynamicalof 30 andMe for SO2 92,8)
isstellar,otherwise
thedisk
would bemass
(21–31
M
e
and
19
–19
lines,
respectively.
visibilities
from baselines larger than 300 kλ (calibration 100of and 500μm and with 1mm (see Figure 8).
3,17
2,18
Only
unstable and would show signiﬁcant asymmetries (e.g., spiralfor small
the data is described in Girart et al. 2018). The resulting
thenotdifference
betweenthe models
radiistructures)(<0 05)thatisareobserved withthe present
data. Suchnoticeable.
amassynthesized
beam haswith
an previous
FWHM observationsof 45.0 mas×38.3
This
is in agreement
at lower
it werethe mainsequence,
an value
Themassive
grain star,sizesif of
the inbest-ﬁt
model
go should
from adevelop
minimum−1(PA=−62°. 4). TheI rms noiseis 60 μJy beamet al.. The HII region, which is not detected with the present observations
angularresolution
andStokes
less sensitivity(Fernández-López
of 0.005μm to a maximum of 3μm in the disk upper layer.
ALMA#2015.1.00480.S
also
had eta al.science
2011b;
Carrasco-González etprojectal. 2012;
Girart2017). goal
We at (see Section 7.1). A possible solution to mitigate this problem
For those grains settled in the disk midplane, the grain sizes are
Bandthat
7 tothere
observeseveralmolecularlines in theemission
298–302note
is alsosigniﬁcant
red/blueshiftedin and is to assume that the star is inﬂated, with low enoughbetween5 andto 500μm.
310–313GHz
frequencysideranges(c40-6temperature
not produce stellar UV radiation and create anthesouthwest/northeastof thedisk.conﬁguration).
This could beHerean weanalyze thediagrams
two of theofbrightestThedensity and temperature proﬁles for the best-ﬁt model
indicationof position–velocity
infall motions, although
MHDofsimulation
disk
HII region.
lines detectedthat better
tracethatthethisdiskcankinematics:
the SOareIn thatin sense,& Omukaifoundaformationand evolutionshows
be a projection
2 shown
FigureHosokawa
9. We founda ﬂared(2009)
disk witha maximum
dependence of the protostellar radius with the accretion rate.
effectsigniﬁcant
inclinations(e.g., Seifried
et al.two
2016).
In
92,8–8for
193,17–19
For thesemolecular
1,7 and2,18 transitions.
orderconstrain
the dynamical
mass fromthese PV maps,
we the They obtain that, in general, the higher the accretion rate, thelines,to thecalibrated
data wereself-calibrated
fromfollowed
theby
procedure
given
Seifried channels
et al. (2016).
Thisfour larger is the stellar radius. Then the protostar has a lower
continuum
using allthebyavailable
in theprocedure
the Keplerian
proﬁleto theemission
observed ﬁts
spectralwindows,
exceptfor5σ
thecontour
channelswith the maximum temperature for a certain stellar mass. This fact
andwas tested
in synthetic
PV maps42,3–31,2). line
Velocity
channel causes a delay in the onset of the main-sequence phase andbrightest
line emission(e.g.,ALMA
H2CO molecular
generated
MHD (after
simulations
for disks
around both
lowmaps werefrom
obtained
continuum
subtraction)using
tclean therefore a delay in the formation of an HII region. Thus,
because of the high accretion rate estimated, we decided toandstars. It should
workanforFWHM
lines that
fully
withhigh-mass
natural weighting,whichbest
yieldedsynthesizedtheresolve, spatially and kinematically, the Keplerian proﬁle in the
beam of 0 21×0 16 (PA=−87°. 1). The channel width was explore large stellar radii, between 10 and 30 Re. Because11
PV maps and−1for cases not too close to a face-on projection. −1 luminosity is known, this implies temperatures between 12,000
.
The
rms
noise
achievedwas
1.3mJybeam
;0.98
kms
and 18,000 K. This is consistent with Johnston et al. (2013),
The best ﬁt obtained yielded an inclination-corrected dynamia

Figure 1. Disk and jet system of the massive star GGD27-MM1. The color
image shows the dust continuum emission of the disk observed with ALMA at
1.14mm with ∼40 mas angular resolution (∼56 au; Girart et al. 2018; see also
our Figure 4). In contours is shown the VLA image at 3.6 cm of the radio jet
observed with an angular resolution of ∼0 4 (Carrasco-González et al. 2012).

Very Large Array (VLA) continuum observations at 7 mmreveal a cross-shaped morphology, which was interpreted as
two overlapping structures that could correspond to the radio
jet and a disk of ∼200 au radius (Carrasco-González et al.
2012), in agreement with the upper limit imposed by the
1.3mm continuum dust emission observations (FernándezLópez et al. 2011a). The size of the putative disk coincides withtheoretical predictions of the centrifugal radius based on the
spectral energy distribution (SED) ﬁtting of some high-mass
protostar regions (De Buizer et al. 2005).
In addition, observed velocity gradients in the molecular gas

per channel. The other molecular lines detected will bewater snow line by looking for spatial variations of the dust
optical depth (e.g., Cieza et al. 2016).
8. Conclusions
We used ALMA continuum observations at 1.14mm,
obtained with an angular resolution of ∼40mas, to model
the accretion disk around the central massive early B-type
protostar exciting the powerful HH80–81 radio jet using the αviscosity prescription. We found an enclosed mass of
21–30 Me, of which 5–7 Mecan be attributed to the disk.
This mass is consistent with the derived dynamical mass of
31±1 Meand 21±1 Mefor the SO2 92,8–81,7 and
193,17–192,18 lines, respectively. The radius of the disk is∼170au, with an inclination angle of 49°. We compared thephysical structure, temperature, and density proﬁles obtainedwith our model with power-law functions, showing that the
GGD27–MM1 system is a potential template for future similar
studies in other high-mass protostars. In particular, we obtained
a ﬂared disk with a maximum scale height of ∼13au and atemperature proﬁle that ranges from ∼150K at the outskirts ofthe disk up to ∼1400K at the inner edge of the disk. The
analysis of the Toomre Q parameter, evaluated at the disk
midplane temperature, indicates that the disk is stable up to aradius Rdisk;100au. This work shows that the D’Alessio
models can be used as a ﬁrst approximation in the modeling ofaccretion disks around massive protostars, providing in
addition several observational predictions.
We also reported the presence of an unresolved compact
source at the center of the accretion disk, with a radius of 4mas(∼5.6 au at the source distance of 1.4 kpc) and a brightness
temperature of ∼104K, most likely tracing ionized gas. The
origin of this compact source is uncertain; it could arise from anincipient, extremely compact HII region or from the base of
the HH80–

midplane temperature, indicates that the disk is stable up to aradius Rdisk;100au. This work shows that the D’Alessio
models can be used as a ﬁrst approximation in the modeling ofaccretion disks around massive protostars, providing in
addition several observational predictions.
We also reported the presence of an unresolved compact
source at the center of the accretion disk, with a radius of 4mas(∼5.6 au at the source distance of 1.4 kpc) and a brightness
temperature of ∼104K, most likely tracing ionized gas. The
origin of this compact source is uncertain; it could arise from anincipient, extremely compact HII region or from the base of
the HH80–81 radio jet. Observations at higher angularresolution would help to determine the nature of this compact
source.
Finally, we have estimated a distance of 1.2–1.4kpc to the
GGD 27 star-forming region based on the Gaia DR2 catalog
combined with near-infrared polarimetric data of the YSOs in
the region and the extinction maps.
We are grateful to Nuria Calvet for making D’Alessio’s code
available to us and for very useful discussions. We would also
like to deeply thank Guillem Anglada for his critical commentson this work that have undoubtedly improved it very
substantially. We thank our anonymous referee for her or hisvery helpful comments and suggestions to improve ourmanuscript. We also thank Rosine Lallement for the support

1212

Charles University in Prague, V Holešovičkách 2, CZ-180 00 Praha 8, Czech Republic; 4 Astronomical Institute, Czech
324 Uncoveringa 260298,
pc wide,Myr oldﬁlamentaryof starforma]on
Academyof Sciences, Fričova
25165, 35
Ondřejov,
Czech
Republic; 5relicInstitutode Astrofísica
de Canarias, E-38205
6
GiacomoBeccari1,
Henri M.J.
Boﬃn1, and Tereza
Jerabkova1,2,3,4,5,6
La
Tenerife,
Spain;
GRANTECAN,
Cuestade San Jose s/n, 38712 Brena Baja, La Palma, Spain#4Laguna,
2020MNRAS.491.2205B (2020/01)

E-mail contact: gbeccari at eso.org

Several recent studies have shown that the Vela OB2 region hosts a complex constellation of sub-populations withages in the range 10 to 50 Myr. Such populations might represent the best example of the outcome of clustered starformation in Giant Molecular clouds (GMC). We use Gaia DR2 data over an area of 40◦ radius around the open cluster
Collinder 135 to extend the study of the stellar populations of the Vela OB2 region over an area of several hundreds ofparsecs on sky. Detailed clustering algorithms combined with the exquisite astrometric quality of the GAIA catalogue
allow us to detect a new cluster named BBJ 1 that shows the same age as NGC 2547 (30 to 35 Myr), but locatedat a distance of 260 pc from it. Deeper investigation of the region via clustering in 5D parameter space and in thecolour-magnitude diagram allows us to detect a filamentary structure of stars that bridges the two clusters. Given theextent in space of such structure (260 pc) and the young age (∼35 Myr), we exclude that such population originates by
the same mechanism responsible to create tidal streams around older clusters. Even if we miss a complete picture of
the 3D motion of the studied stellar structure because of the lack of accurate radial velocity measurements, we proposethat such structure represent the detection of a 35 Myr old outcome of a mechanism of filamentary star formation ina GMC.
Accepted by MNRAS
http://arxiv.org/pdf/1911.05709

The Forgotten Quadrant Survey. 12 CO and 13 CO (1–0) survey of the Galactic Plane in
the range 220◦ < l < 240◦ −2.◦ 5 < b < 0◦
M. Benedettini1, S. Molinari1 , A. Baldeschi2,1 , M.T. Beltrán3 , J. Brand4
6

13

INAF – Istituto di Astrofisica e Planetologia Spaziali,
via Fossodel Cavaliere 100, 00133 Roma, Italy; 2 Center for
12
13
324 The Forgo{enQuadrant
Survey.
CO andandCO(1–0) surveyof thePlane
in theInterdisciplinary
Exploration
and Researchin Astrophysics
Departmentof Physics
and Galac]c
Astronomy,
Northwestern◦.5<b<0◦
University,
Evanston,
60208;◦ 3−2
INAF– Osservatorio
Astrofisico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy;#5 range220◦ IL<l<2401

4

M. BenedeIni1, S. Molinari1, A. Baldeschi2,1, M.T. Beltrán3, J. Brand4
arXiv:1911.11545 (2019/11)

14

Bertrand Lefloch1
Univ. Grenoble
Alpes, CNRS,
Grenoble,
France; 2 INAF-Osservatorio
di Arcetri, L.go E.
324
Astrochemistry
as a IPAG,
tool to38000
follow
the protostellar
evolu]on: theAstrofisicoClass I stage
Fermi 5, Eleonora
I-50125Bianchi1,
Firenze,Cecilia
ItalyCeccarelli1, Claudio Codella2,1, Juan Enrique-Romero1, Cecile Favre1 and Bertrand Leﬂoch1#6 arXiv:1911.08991(2019/11)
1

E-mail contact: eleonora.bianchi at univ-grenoble-alpes.fr

The latest developments in astrochemistry have shown how some molecular species can be used as a tool to study
the early stages of the solar-type star formation process. Among them, the more relevant species are the interstellar
complex organic molecules (iCOMs) and the deuterated molecules. Their analysis give us information on the present
and past history of protostellar objects. Among the protostellar evolutionary stages, Class I protostars represent a
perfect laboratory in which to study the initial conditions for the planet formation process. Indeed, from a physicalpoint of view, the Class I stage is the bridge between the Class 0 phase, dominated by the accretion process, and theprotoplanetary disk phase, when planets form. Despite their importance, few observations of Class I protostars exist
and very little is known about their chemical content. In this paper we review the (few) existing observations of iCOMs
and deuterated species in Class I protostars. In addition, we present new observations of deuterated cyanoacetylene
and thioformaldehyde towards the Class I protostar SVS13-A. These new observations allow us to better understandthe physical and chemical structure of SVS13-A and compare the cyanoacetylene and thioformaldehyde deuteration
with other sources in diﬀerent evolutionary phases.
Accepted by ACS Earth and Space Chemistry
http://arxiv.org/pdf/1911.08991

The dry and carbon poor inner disk of TW Hya: evidence for a massive icy dust trap
Arthur D. Bosman1 and Andrea Banzatti2
Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands; 2 Department of Physics,
Texas State University, 749 N Comanche Street, San Marcos, TX 78666, USA
1

7

15

Amphur Maerim, Chiang Mai, 50180, Thailand; University of Science and Technology, Korea (UST), 217 Gajeongro, Yuseong-gu, Daejeon 34113, Republic of Korea; 19 Astronomical Observatory, Ural Federal University, Lenin
32451, VLBI
observa]onsof the 20
G25.65+1.05
water fürmasersuperburstAuf dem Hügel 69, 53121 Bonn,
Ave.
Ekaterinburg
620083, Russia;
Max-Planck-Institut
Radioastronomie,
21 A. Burns1,2,3, Gabor Orosz4,5, Olga Bayandina1,6, Gabrielle Surcis7, Mateusz Olech8, Gordon MacLeod9,10, Alexandr#9 Ross
Germany;
Netherlands Institute for Radio Astronomy, Oude Hoogeveensedijk 4, 7991 PD Dwingeloo; 22 NRAO,
Volvach6,11, Gerogij Rudnitskii12, Tomoya Hirota2, Katharnia
23 Immer1, Jay Blanchard1,13, Benito Marcote1, Huib van
520 Edgemont
Road,Charlottesville,
VA
22903,
USA;
Instituto
Radioastronomia
y Astrofisica,
Universidad
Langevelde1,14, James O. Chibueze15,16, Koichiro Sugiyama2,17,
Kee-Taede
Kim3,18,
Irina
Val{s6, Nadya
Shakhvorostova6,19,
24
NacionalBusaba
Autonomade Mexico,Morelia
58089, Meexico;di Radioastronomia
Kramer17,20,
WillemApartado
A. Baan5,21,Postal
Crystal 3-72,
Brogan22,
Todd Hunter22,
Stan Kurtz23,INAF-Istituto
Andrey M. Sobolev19,
Jan Brand24 andand Italian
ALMA
Regional Centre, via P. Gobetti 101, 40129, Bologna, Italy
LarisaVolvach6,112020MNRAS.491.4069B (2020/01)
E-mail contact:
rossburns88 at googlemail.com

This paper reports observations of a 22 GHz water maser ‘superburst’ in the G25.65+1.05 massive star forming region,
conducted in response to an alert from the Maser Monitoring Organisation (M2O). Very long baseline interferometry(VLBI) observations using the European VLBI Network (EVN) recorded a maser flux density of 1.2 × 104 Jy. The
superburst was investigated in the spectral, structural and temporal domains and its cause was determined to be anincrease in maser path length generated by the superposition of multiple maser emitting regions aligning in the lineof sight to the observer. This conclusion was based on the location of the bursting maser in the context of the star
forming region, its complex structure, and its rapid onset and decay.
Accepted by MNRAS
http://arxiv.org/pdf/1911.12634

The dynamically young outflow of the Class 0 protostar Cha-MMS1
L.A. Busch1,2 , A. Belloche1 , S. Cabrit3,4 , P. Hennebelle5, B. Commerco̧n6Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany; 2 Argelander-Institut fr Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany; 3 LERMA, Observatoire de Paris, PSL
Research University, CNRS, Sorbonne Université, UPMC Univ. Paris 06, 75014 Paris, France; 4 Université Grenoble
Alpes, CNRS, IPAG, 38000 Grenoble, France; 5 AIM, CEA, CNRS, Université Paris-Saclay, Université Paris Diderot,
Sorbonne Paris Cité, 91191 Gif-sur-Yvette, France; 6 Centre de Recherche Astrophysique de Lyon UMR5574, ENS de
Lyon, Univ. Lyon1, CNRS, Université de Lyon, 69007 Lyon, France
1

E-mail contact: labusch at mpifr-bonn.mpg.deOn the basis of its low luminosity, its chemical composition, and the absence of a large-scale outflow, the dense core
Cha-MMS1 located in the Chamaeleon I molecular cloud was proposed as a first hydrostatic core (FHSC) candidate
16
a decade ago. Our goal is to test this hypothesis by searching for a slow, compact outflow driven by Cha-MMS1 that324 The dynamically young ou€low of the Class 0 protostar Cha-MMS1
Busch1,2, A. Belloche1, S. Cabrit3,4, P. Hennebelle5, B. Commerco ̧n6#10 L.A.
arXiv:1911.11194 (2019/11)

17