国立天文台

楠根

#318
17 Star-planet tidal interaction and the limits of gyrochronology
18 Gaia Stellar Kinematics in the Head of the Orion A Cloud: Runaway Stellar Groups andGravitational Infall
19 Modelling the Spatial Distribution and Origin of CO Gas in Debris Disks
20 Dust Polarization in Four Protoplanetary Disks at 3 mm: Further Evidence of Multiple Origins
21 Gas and Dust Properties in the Chamaeleon Molecular Cloud Complex based on the OpticallyThick HI22 APEX Millimeter Observations of Methanol Emission Toward High-Mass Star-Forming Cores
23 Investigating the Eﬃciency of Explosion Chemistry as a Source of Complex Organic Molecules
in TMC-1
24 Nobeyama 45-m Mapping Observation toward Orion A. II. Classiﬁcation of Cloud Structures
and Variation of the 13CO/C18O Abundance Ratio due to far-UV Radiation
25 The Milky Way Project Second Data Release: Bubbles and Bow Shocks
26 When the tale comes true: multiple populations and wide binaries in the Orion Nebula Cluster

20 Dust Polarization in Four Protoplanetary Disks at 3 mm: Further Evidence of Multiple
Origins
Rachel E. Harrison1 , Leslie W. Looney1 , Ian W. Stephens2 , Zhi-Yun Li3 , Haifeng Yang3,4 , Akimasa
Kataoka5 , Robert J. Harris1,6 , Woojin Kwon7,8 , Takayuki Muto9 and Munetake Momose10
1Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 W. Green St., Urbana, IL 61801,
USA; 2 Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA; 3 Department
ALMAを使って、6つのClass
II天体 (DG Tau、Haro 6-13、RY Tau、MWC 480)を偏波観測@3mm
of Astronomy, University of Virginia, Charlottesville, VA 22903, USA; 4 Institute for Advanced Study, Tsinghua
4
University, Beijing, 100084, Peoples Republic of China; 5 National Astronomical Observatory of Japan, 2-21-1 Osawa,
Mitaka, Tokyo 181-8588, Japan; 6 National Center
for Supercomputing Applications, University of Illinois at Urbana偏光強度マップに偏波ベクトルをプロット（コントアはStokes
I）
Champaign, 1205 W Clark St, Urbana, IL 61801, USA; 7 Korea Astronomy and Space Science Institute (KASI), 776
Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Republicof Korea; 8 University of Science and Technology, Korea (UST),
偏波ベクトルの形状は２つのカテゴリーに分けられる：
217 Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea; 9 Division of Liberal Arts, Kogakuin University,
10
Tau・Haro
azimuthalなベクターパターン
1-24-2 Nishi-Shinjuku, Shinijuku-ku, Tokyo, 163-8677,DG
Japan;
College of6-13：
Science, Ibaraki
University, 2-1-1 Bunkyo,
Mito, Ibaraki 310-8512, Japan＋ 中心付近に２つの非偏波ホール(a)E-mail contact: reh3 at illinois.edu(b)

RY Tau・MWC 480：

円盤の短軸に平行

We present polarimetric observations of four Class II protoplanetary disks (DG Tau, Haro 6-13, RY Tau, and MWC＋ 偏波は中心付近のみ480) taken with the Atacama Large Millimeter/submillimeter Array (ALMA) at 3 mm. The polarization morphologies
observed fall into two distinct categories: azimuthal polarization (DG Tau and Haro 6-13) and polarization parallel=> これらの２つの特徴は、偏光強度vs.中心からの距離の図
to the disk minor axis (RY Tau and MWC 480). The mechanisms responsible for disk polarization at millimeterand submillimeter wavelengths are currently under debate.
In this Letter, we investigate two mechanisms capable（下）にも見られるof producing polarized dust emission in disks: self-scattering and grain alignment to the radiation anisotropy. The
polarization morphologies of DG Tau and Haro 6-13 are broadly consistent with that expected from radiation alignment
長軸方向
短軸方向
(though radiative alignment still does not account for all of the features
seen in these disks), while RY Tau andMWC
480 are more consistent nation
withself-scattering. Such a variation in the polarized morphology may provide evidence of
The polarization morphology observed in Haro 6-13
and position angle, as well as the beam size andand DG Tau at 3 mm resembles that observed in HL
position angle, for one of four mechanisms: Rayleighdust
diﬀerences
betweenthe mechanicalsources.
Tau atthe same grain
wavelength. size
RY Tau and
MWC 480,
scattering,radiative alignment,alignment
DG
TauとHaro
6-13：
5Total and Polarized Intensities Beam Sizes, and Inclination Angles for all Sources

SourceDG TauHaro 6-13
MWC 480
RY TauV892 TauDL Tau(c)(d)

Inc. (i)
32
40 .
36
65
59
45

I flux (mJy)
42.71 ± 0.64
24.96 ± 0.08
23.21 ± 0.41
29.50 ± 0.09
44.22 ± 0.22
32.90 ± 0.36

I (µJy/beam)

16.0
19.2
17.7
29.7
28.1
23.5

P peak (µJy/beam)
127
129
96.2
243
<128
<124

P

(µJy/beam)
15
16
15.8
19
43
42

Beam Size
0.00 23⇥0.00 22
0.00 27⇥0.00 22
0.00 43⇥0.00 30
0.00 33⇥0.00 26
0.00 26⇥0.00 20
0.00 24⇥0.00 19

Table 1. Total and polarized intensities beam sizes, and inclination angles for all sources. 3 upper limits on polarized intensity
are given for V892 Tau and DL Tau. Inclination angles for V892 Tau and DL Tau from Hamidouche (2010) and Long et al.

Figure 1. Images of DG Tau, Haro 6-13, MWC 480, and RY Tau at 3 mm. The contours represent total intensity (Stokes I)(2018), respectively.
of -3 (dashed), 3, 10, 50, 100, 250, and 500 levels, where is listed in Table 1. The colormap represents polarized intensitywith the scale on the right of each source. The length of the polarization vectors corresponds to the polarization fraction. The
vectors are plotted with ⇠ 5 segments per beam.

however, exhibit polarization parallel to the disk minor
axis, similar to HL Tau at 870 µm. This comparison isstill true regarding the way polarized intensity changes
across the disks. These di↵erences at the same wavelength for the two groups of sources implies di↵erent
polarization mechanisms for very similar sources.
To explore if these di↵erences could be attributed toinclination or signal-to-noise, we compared the observed
polarization patterns to those predicted from a simple
model. The model creates a map of the polarized intensity and polarization angle based on the disk’s incli-

Accepted by ApJL

through the Gold mechanism (as described in Gold1952), and alignment to a toroidal magnetic field. In
the radiative model, the polarization angle is calculatedby rotating the radial direction in the disk plane by 90 .
The polarization angle in the case of mechanical alignment through the Gold mechanism is the position angle of the toroidal direction in the sky plane, and thepolarization angle in the case of magnetic alignment isperpendicular to the toroidal direction. In the case of
self-scattering, the model sets the polarization angle parallel to the disk’s minor axis. The polarization fraction

6

HK Tauの3mmの結果に似ている
http://arxiv.org/pdf/1905.06266

(a)

(b)

(a)

(b)

MWC 480とRY Tau：
GasTauの870µmの結果に似ている
and Dust Properties in the Chamaeleon Molecular Cloud Complex based on theHK
Optically Thick HI
K. Hayashi1 , R. Okamoto1 , H. Yamamoto1 , T. Hayakawa1 , K. Tachihara1 and Y. Fukui2,1
1

(c)

(d)

(c)

Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan; 2 Institute for Advanced
似通った天体で異なる偏光メカニズム？
赤：偏波強度、青：偏光度
Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
Figure 2. Polarized intensity and percent polarization vs. distance from Stokes I peak along the major axes of the disks. The
shaded areas represent ±1 statistical uncertainties. Positive distances correspond to north and west of the Stokes I peak for
DG Tau, Haro 6-13, and MWC 480, and south and west of the Stokes I peak or RY Tau.

produced by the three alignment mechanisms (radiative,
magnetic, and mechanical) depends on the cosine of theangle between the dust grain alignment axis and the lineof sight direction. The polarization fraction produced byby a simple model for the disk brightness to give thepolarized intensity. Because the models are inherently
axisymmetric, they cannot explain any of the asymmetry observed in polarized intensity.

(d)Figure 3. Polarized intensity and percent polarization vs. distance from Stokes I peak along the projected minor axes of thedisks. The shaded areas represent ±1 statistical uncertainties. Errors on polarization fraction are only shown in regions whereP > 0. Positive distances correspond to south and west of the Stokes I peak for DG Tau, Haro 6-13, and MWC 480, and northand west of the Stokes I peak for RY Tau.

from Figure 1. Comparison with our simple modelshows that the polarization in DG Tau and Haro 6-13 isbroadly consistent with that expected from grain align-

polarized emission would peak at two points along the
major axis in RY Tau and MWC 480. Additionally, we
note that while Haro 6-13 and MWC 480 have nearlyシンプルなモデルと観測結果を比較した（レイリー散乱、輻射整列、Goldメカニズムによる力学的整列、toroidal磁場による整列）
7

DG Tau・Haro 6-13
輻射の異方性に対する整列モデルとほぼ一致：

(a)

(b)

azimuthallyな偏波パターン
beam averagingによる２つの低偏光ホール@長軸の両サイド
cf. Goldメカニズムによる力学的整列の場合、
azimuthallyな偏光パターンだが、円盤の短軸の両サイドに低偏波ホール

8

(c)

(d)

Figure 4. Models of expected polarization morphology in DG Tau and Haro 6-13 from radiative alignment , alongside the maps
from Figure 1. In models, gray contours represent Stokes I, blue shading represents polarized intensity, and black pseudo-vectors
represent polarization angle. The color scale is relative and not meant to quantitatively predict polarized intensity values.

The di↵erences in polarization mechanisms in thesedisks may indicate that the disks are at di↵erent stagesof evolution. Polarization from scattering is present at alonger wavelength in MWC 480 and RY Tau than in HL
Tau. This could indicate that MWC 480 and RY Tau
have (compared to HL Tau) larger dust grains, which
could imply a more evolved disk with time to allow dust
to grow to larger sizes. To determine whether evolutionary e↵ects are responsible for the variation seen in thesedisks, we will need observations at other wavelengths
to determine more quantitatively where the transitions
between polarization patterns(a)take place.
The dust opacity spectral index ( ) has been used toestimate grain sizes in circumstellar disks with assumed
dust properties. Kwon et al. (2015) obtained valuesof 0.6745 ± 0.0069 (viscous accretion disk model) to
0.615 ± 0.006 (power-law disk model) for HL Tau and(c)values consistent with zero or a small positive number for Haro 6-13. Even with the uncertainty of 0.25
on these values, HL Tau’s value is higher than Haro
6-13’s, which is consistent with Haro 6-13 being a more
evolved disk. The similar polarization morphologies, on
the other hand, imply that the two disks have similar
grain sizes. However, there is an order of magnitude discrepancy between the grain size estimates from Rayleighscattering and those from in HL Tau; scattering gives
an estimated maximum grain size of up to ⇠150 µm,
while gives a maximum grain size of ⇠1 mm (Kataoka
et al. 2016). The cause of (b)this discrepancy is currently
unknown.

RY Tau・MWC 480
散乱モデルとほぼ一致：
円盤短軸に沿った偏波ベクトル
偏光強度のピークは円盤中心

4.2. Problems with the radiative alignment model
Although HL Tau’s 3 mm polarization morphology
has been used as an example of radiation alignment, it

cf. 輻射整列モデルの場合、偏光emissionのピークが長軸に沿った2点に現れる(d)

HL Tauでは観測波長によって偏光パターンに違いがあったが、今回の観測では似た円盤を同じ波長で見ても異なる偏波パターンとなる初めての結果

Figure 5. Models of expected polarization morphology in MWC 480 and RY Tau from scattering, alongside the maps from
Figure 1. In models, gray contours represent Stokes I, blue shading represents polarized intensity, and black pseudo-vectors
represent polarization angle. The color scale is relative and not meant to quantitatively predict polarized intensity values.

is not well fit by this mechanism (Yang et al. 2019).
The polarization pattern of HL Tau is very similar to
DG Tau and HH 6-13 in Figure 1, which is an elliptical polarization pattern. However, radiatively aligned
grains produce an intrinsically circular polarization pattern even for inclined disks such as HL Tau. To recreate the elliptical pattern, Yang et al. (2019) used theplete models that include 3D descriptions of the radiation and disk will be necessary to constrain the mechanism or mechanisms responsible for polarized emission
in these disks.
5. CONCLUSIONS

These observations represent the largest survey of pro-

●偏光メカニズムの違いは、円盤の進化ステージの違いを示す？
散乱による偏光では、MWC 480やRY TauはHL Tauよりも長波長で観測されている-> HL Tauよりも大きなダストサイズ？より進化した円盤？
β（dust opacity spectral index）を使ってダストサイズを見積もる
HL Tau：β ~ 0.6745 - 0.615
Haro 6-13：β ~0=> Haro 6-13の方がより進化した円盤？

※ HL Tauにおいて、レイリー散乱で求めたダストサイズ（~150µm）とβから求めたダストサイズ（~1mm）は一致していない。
●輻射整列の問題
DG TauとHH 6-13の偏波パターンはHL Tauに酷似していて、楕円型のパターン
しかし、輻射整列は円型の偏波パターンになる（円盤の傾きを考慮しても）Aerodynamic整列（Gold 1952）だと楕円形パターンが再現できる（Yang+19）
しかし、偏光強度がAzimuthalに変化し、その傾向はHL TauやDG Tau、HH 6-13では見られていない

26 When the tale comes true: multiple populations and wide binaries in the Orion Nebula
Cluster
Tereza Jerabkova1,2,3 , Giacomo Beccari1 , Henri M.J. Boﬃn1 , Monika G. Petr-Gotzens1 , Carlo F.
Manara1 , Pier Giorgio Prada Moroni4,5 , Emanuele Tognelli4,5 , and Scilla Degl’Innocenti4,51European Southern Observatory, Karl-Schwarzschild-Straße 2, 85748 Garching bei München; 2 Helmholtz Institut背景für Strahlen und Kernphysik, Universität Bonn, Nussallee 14–16, 53115 Bonn, Germany; 3 Astronomical Institute,Charles University in Prague, V Holesovickách 2, CZ-180 00 Praha 8, Czech Republic; 4 Department of Physics “E.
Orion
Cluster周辺3
3 の 3, I-56127 Pisa, Italy; 5 INFN, Sezione di Pisa, Largo Bruno
Fermi”,Nebula
Universityof Pisa, (ONC)
Largo Bruno
Pontecorvo
Pontecorvo 3, I-56127 Pisa, Italy
ハイクオリティなOmegaCAM（rとiバンド）撮像結果が近年報告された：
E-mailcontact: tjerabkova at gmail.com- 色等級図において、３つの前主系列populationに分かれる
The high-quality OmegaCAM photometry of the 3×3 deg around the Orion Nebula Cluster (ONC) in r, and i filters- それら前主系列に属する天体は、ONCの中心に集中している。
by Beccari et al. (2017) revealed three well-separated pre-main sequences in the color-magnitude diagram (CMD).
- 著者「２つの競合シナリオ」：
The
objects belonging to the individual sequences are concentrated towards the center of the ONC. The authors
concluded that there are two competitive scenarios: a population of unresolved binaries and triples with an exotic- 空間分解されていない連星/三重星のpopulation（逸脱した質量を持つ）
mass ratio distribution, or three stellar populations with diﬀerent ages. We use Gaia DR2 in combination with the- 異なる年齢（~1Myr間隔）の３つのpopulation
photometric
OmegaCAM catalog
to test and confirm the presence of the putative three stellar populations. We also
study multiple stellar systems in the ONC for the first time using Gaia DR2. We confirm that the second and third
目的sequence members are more centrally concentrated towards the center of the ONC. In addition we find an indicationthat the parallax and proper motion distributions are diﬀerent among the members of the stellar sequences. The age
Gaia
DR2とOmegaCAMカタログを使って、想定される3つのpopulationの存在を確かめる
diﬀerence
among stellar populations is estimated to be 1–2 Myr. We use Gaia measurements to identify and remove as
manyDR2を使ってONCでの多重連星系の研究を初めて行う
unresolved multiple system candidates as possible. Nevertheless we are still able to recover two well-separated
Gaia
sequences with evidence for the third one, supporting the existence of the three stellar populations. We were able toidentify a substantial number of wide binary objects (separation between 1000–3000 au). This challenges previously方法
inferred values that suggested no wide binary stars exist in the ONC. Our inferred wide-binary fraction is ≈ 5%.
視差と固有運動を基にONCメンバーをセレクトし、混みいった領域ではGaia
DR2よりも良い
We confirm the three populations correspond to three separated episodes of starformation. Basedon this result, we
T. Jerabkova and G. Beccari et al.: Three stellar populations and wide binaries in the ONC
concludethatstarformationisnothappeninginasingle
burst
in
this
region.
PhotometoryのOmegaCAMのものを利用する
15.6

Accepted by A&A

60

15.8

http://arxiv.org/pdf/1905.06974

結果1

50

16.2

The two magnetic components in the Herbig Ae SB2 system HD 104237
２つの明確に分かれるsequenceを同定（→）
1

1

1

1

16.4

2

S.P. Järvinen , T.A. Carroll , S. Hubrig , I. Ilyin , M. Schöller , N.A. Drake
1

3,4

16.6

object countsr [magAB ]

16.0
40
30

and M.A.20Pogodin5

10Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany; 2 European
South16.8
3
ern Observatory, Karl-Schwarzschild-Str 2, 85748 Garching, Germany; Laboratory of Observational 0 Astrophysics,
17.0
4
0.5
1.0
1.5
0.00
0.25
0.50
0.2
0.0
0.2
0.4
Saint Petersburg State University, Universitetsky pr. 28, 198504 SaintPetersburg,
Russia;Laboriteório
Nacional(r i) [mag ]
AB

(r

i)

5

(r

i)

is quantitatively comparable to the Fig. 3.

第二・第三populationはONCの中心により集中している（→）
Dec [deg]

T. Jerabkova and G. Beccari et al.: Three stellar populations and wide binaries in the ONC

視差と固有運動の分布：populationで異なっている

30
20
10

Pisa等時線を使ってpopulationの年齢を見積もる

R.A. + 3 deg

4

0
0.75

5

4.3. The appare6

populationの中での年齢の違いは1-2 Myrと見積もられる

pm Dec. [mas/yr]

T. Jerabkova and G. Beccari et al.: Three stellar populations and wide binaries in the ONC
0.50

7

0.25

83

0.25

0.5

1.0
1.5
pm R.A. [mas/yr]

10

20

85
86
R.A. [deg]87Fig. 5. The R.A. - Dec distribution of the first and second sequence
identified in Fig. 3. To compare on-the-sky distributions of the "old"and "young" sequences we use two-dimensional Kolmogorov-Smirnov
test (Peacock 1983; Fasano & Franceschini 1987; Press et al. 2007)
resulting in p = 0.01 (⇡ 2.3 ).

30

Fig. 6. Left panel: distribution of the parallax, $, of the identified main-ridge sequence (blue), second +third sequence (orange). The top horizontal
axis shows corresponding values, d, in parsec using d[pc] = 1/($[mas] · 10 3 ), valid for those objects that have small relative errors (Gaia
Collaboration et al. 2018). Right panel: the R.A. and Dec proper motions with the histograms of projected distributions on the sides of the plot.

結果2

84

T. Jerabkova and G. Beccari et al.: Three stellar populations and wide binaries in the ONC

0.00

tions: 1) the spread is caused by unresolved binary stars and 2)
the spread is actually due to multiple populations.

in preparation).

the distribution, r
The best fitting p
agepop1 = 4.5+1.5
1.2
agepop2 = 2.1+0.5
0.4+0.3
agepop3 = 1.4 0.2
with E(B-V)=0.0
B17. The corres
isochrones are sh

After applying se
C3 we expect to
PMS stars. Howe
noticeable groupthat is, the objec
et al. (2013) studintermediate resoan accurate met
the related age ostars are actuallyconclude that, if
then especially folike the here usedscattered from th
accretors are mosblue-wards scattethese bluer target

Article number, page 8 of 17
5. Apparent binary and triple systems
Gaiaの固有運動と他の測定を使い、可能な限り多くの分解されていない多重星系候補を同定し取り除いた

Fig. 6. Left panel: distribution of the parallax, $, of the identified main-ridge sequence (blue), second +third sequence (orange). The top horizontal
3

axis shows corresponding values, d, in parsec using d[pc] = 1/($[mas] · 10 ), valid for those objects that have small relative errors (Gaia
In the previous section we investigated the impact of unresolved
Collaboration et al. 2018). Right panel: the R.A. and Dec proper motions with the histograms of projected distributions on the sides of the plot.
binaries on the detection of multiple populations among the PMSof the ONC. We are now interested in exploiting the potential
in preparation).
of the Gaia DR2
combination
with theOmegaCAM
Fig.catalog
6. Leftinpanel:
distributionof theparallax, $, of the identified main-ridge sequence (blue), second +third sequence (orange). The top horizontal
photometry toaxis
investigate
resolved
multiplesystems.
The
seeing3
shows corresponding values, d, in parsec using d[pc] = 1/($[mas] · 10 ), valid for those objects that have small relative errors (Gaialimited OmegaCAM photometry aims at resolving binaries hav5. Apparent
binary andon
tripleCollaboration et al. 2018). Right panel: the R.A. and Dec proper motions with the histograms of projecteddistributions
thesystems
sides of the plot.
ing separations ' 0.7”. While the resolution of Gaia DR2 is 0.4",
In the previous section we investigated the impact of unresolved
Ziegler et al. (2018) show that
Gaia is only able to reliably re00
binaries on the detection of multiple populations among the PMS
cover all binaries down to 1.0 at magnitude contrast as large asof the ONC. We are now interested in exploiting the potentiallog(separation[AU])
6 magnitudes.in preparation).
of the Gaia DR2 catalog in combination with the OmegaCAM
to investigate resolved
2.2
3.2 photometry4.2
5.2 multiple systems.
6.2 The seeing
One method to investigate resolved apparent binary candilimited OmegaCAM photometry aims at resolving binaries havdates is to construct the so-called Elbow plot (e.g., Larson 1995;
7
ing separations ' 0.7”. While the resolution of Gaia DR2 is 0.4",
Gladwin et al. 1999). The method consists in calculating the disZiegler et al. (2018) show that Gaia is only able to reliably recover all binaries down to 1.0 at magnitude contrast as large astribution of the number density of observed targets (⌃) as a func6 magnitudes.
5. Apparent
binaryandtriple systems
6tion of on-the-sky
separation (✓).
As shown
in Gladwin
et al.
One method to investigate resolved apparent binary candiFig.
7.
The
Elbow
plot
showingthesurfacenumberdensityasa func(1999) the presence of an elbow in the density distribution dedates is to construct the so-called Elbow plot (e.g., Larson 1995;
tion of separationon the sky. The black dashed line shows the originalIntheprevious
sectionwe
investigatedtheimpactofunresolved
et al. 1999). The method consists in calculating the disscribed above is caused by the presence of resolved binaries. In Gaia data sample, the black solid line shows
5 the cross-matched,Gladwinthat is, of the number density of observed targets (⌃) as a functribution
the detectionof multiple
populations
the PMS
short, for eachbinaries
star in ouron
catalog
we divide thesurroundingarea initial,amongcatalog after the C1 and 2- C2 are applied. We fit the elbow
tion partof on-the-sky separation (✓). As shown in Gladwin et al.
7. The Elbow plot showing the surface number density as a funcof sky into a of
set theof annuli,
drawingof radius ✓i in
cen-exploiting
ONC.by We
are circles
now interestedthepotentialof the diagram obtaining a slope value 41.7 ± 0.05. The gray data(1999)
pointsthe presence of an elbow in the density distribution de- Fig.
tion of separation on the sky. The black dashed line shows the original
scribedtered on the star,
withGaia✓i = 2✓
i 1. in✓0 ischosen to be withi 1 andand theslope are from Simon (1997) having a smaller field ofviewabove is caused by the presence of resolved binaries. In Gaia data sample, the black solid line shows the cross-matched, that is,of theDR2catalog
combination
theDMOmegaCAM
short,
for
each
star
in
our
catalog
wedividethesurrounding
area
well below the smallest separation in the sample. Next we count by using the HST. The gray line is the Duquennoy & Mayor (1991) disinitial, catalog after the C1 and 2- C2 are applied. We fit the elbow partphotometry to investigate resolved multiple systems. The seeingof sky into a set of annuli, by drawing circles of radius ✓i cen- of the diagram obtaining a slope value 1.7 ± 0.05. The gray data points
3 that has been reformulated
the number of companion stars in each annulus and we calculate tribution of binary stars of G-type primaries
tered on the star, with ✓i = 2✓i 1 and i 1. ✓0 is chosen to be and the DM slope are from Simon (1997) having a smaller field of view
limited OmegaCAM photometry aims at resolving
binariesto the number
densityhav⌃ by Gladwin et al. (1999) (their eq. (5)).
the ⌃(✓)i as follows,
wellThebelow the smallest separation in the sample. Next we count by using the HST. The gray line is the Duquennoy & Mayor (1991) dis-

かなりの数の広い連星（1000-3000 auの間隔）を同定でき、連星成分の相対固有運動は０

これは、以前示唆された結果（ONCには広い連星は存在しない;
ing separations ' 0.7”. While the resolution of Gaia DR2 is 0.4",
N
Ziegleretonly able to reliably re⌃(✓) =, al. (2018) show that Gaia is(5)Salcally+99）と異なる
⇡N (✓
✓ all
) binaries down to 1.0 at magnitude contrast as large ascover
6 magnitudes.
where N is thenumber of stars in the ith bin, N is the totalof stars and✓ = (✓+ ✓ )/2
the angular separationOne
methodtoisinvestigate
resolvedofapparent binary candiまた連星の比率は約5%と推定number
measured sources.
dates is to construct the so-called Elbow plot (e.g., Larson 1995;
i

i

tot

2
i

2
i 1

00

i

tot

i

まとめ

i 1

00

)

結果3

-> 3つのpopulationの存在を支持する

log(number densityにもかかわらず、2つのpopulationをrecoverできているvertical lines (from left to right) are the resolution limit of GaiatheDR2,
number of companion stars in each annulus and we calculate2⌃(✓)i as follows,
the resolution limit of OmegaCAM, respectively,
the first red linetheshows(1 · 103 au) as the definition of wide binaries, and the last line shows theNi⌃(✓)con,(5)
i =start of the Elbow feature (3 · 103 au).1 The color histograms are⇡Ntot (✓i2 ✓i2 1 )structed for central circular regions (see Fig. 8 ) to see how the potential
where Ni is the number of stars in the ith bin, Ntot is the totalof detection of wide binaries changes with the chosen spatial region.

0-4

number of stars and ✓ = (✓i + ✓i 1 )/2 is the angular separation of-3 measured sources.
-2

-1

0

tribution of binary stars of G-type primaries that has been reformulated
to the number density ⌃ by Gladwin et al. (1999) (their eq. (5)). The
vertical lines (from left to right) are the resolution limit of Gaia DR2,
the resolution limit of OmegaCAM, respectively, the first red line shows(1 · 103 au) as the definition of wide binaries, and the last line shows thestart of the Elbow feature (3 · 103 au). The color histograms are constructed for central circular regions (see Fig. 8 ) to see how the potentialof detection of wide binaries changes with the chosen spatial region.

We show in Fig. 7 the Elbow plot as calculated using the
We show in Fig. 7 the Elbow plot as calculated using the
Gladwin et al. 1999). The method consists in calculating the disstars sampled with the Gaia DR2 catalog alone (black dashed the other hand keeps the data sample as complete as possible.
log(separation[deg]) with the OmegaCAM cata- The slope of the elbow is 1.70 ± 0.05 which suggests incomstars sampled with the Gaia DR2 catalog alone (black dashed the other hand keeps the data sample as complete as possible.
line) andGaia DR2 cross-matchedof the number
densityof observed
targets
func-is 1.70 ± 0.05 which suggests incomline) and Gaiatribution
DR2 cross-matchedwith theOmegaCAM
cata- The
slope(⌃)
of as
the aelbow
log (black solid line). We applied the C1 and 2 C2 criterion to plete data sample toward smaller separations as slope values forboth forcatalogs. The C1 and 2 C2 criterion reduces significantly complete samples in binary-devoted studies are ⇡ 2 (Gladwin
tion
of We
on-the-sky
As shown
indataGladwinet al. smaller separations as slope valueslog (black solidline).
applied theseparation
C1 and 2 C2(✓).
criterion
to pletesample toward
the contamination
by objects
not belonging
to the as
ONC,
but on et al. 1999). This is consistent with the recovery completenessElbow
showing
the surface
numberdensitya funcboth catalogs.(1999)
The C1 theand 2presenceC2 criterion
reducessignificantly
completesamples in binary-devoted
studiesare ⇡plot
2 (Gladwin
of an
elbow
in the density
distribution
de- Fig. 7. The
tionwithof separation
the sky. The black dashed line shows the original
Article number, page 9 of 17
the contamination
by objects
to thebut onof etal. 1999).binaries.
This is consistent
the recoveryoncompletenessscribedabovenotis belonging
caused by
theONC,
presence
resolvedIn

short, for each star in our catalog we divide the surrounding areaof sky into a set of annuli, by drawing circles of radius ✓i centered on the star, with ✓i = 2✓i 1 and i 1. ✓0 is chosen to bewell below the smallest separation in the sample. Next we countthe number of companion stars in each annulus and we calculatethe ⌃(✓)i as follows,

Gaia data sample, the black solid line shows the cross-matched, that is,
Article number,of 172- C2 are applied. We fit the elbow part
initial, catalog
after thepage
C19andof the diagram obtaining a slope value 1.7 ± 0.05. The gray data points
and the DM slope are from Simon (1997) having a smaller field of viewby using the HST. The gray line is the Duquennoy & Mayor (1991) distribution of binary stars of G-type primaries that has been reformulated
to the number density ⌃ by Gladwin et al. (1999) (their eq. (5)). The
vertical lines (from left to right) are the resolution limit of Gaia DR2,
the resolution limit of OmegaCAM, respectively, the first red line shows(1 · 103 au) as the definition of wide binaries, and the last line shows the

３つに別れた星形成episodeに対応する３つのpopulatioinを確かめた
この結果に基づき、この領域では星形成は単一バーストでは起きていないと結論づける
さらにONCにおいて、存在しないと思われていた広い連星5%を同定
N⌃(✓) =,(5)ii⇡Ntot (✓i2

✓i2 1 )

3

17 Star-planet tidal interaction and the limits of gyrochronology
Florian Gallet1 and Philippe Delorme1
1

背景 Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France星の自転周期から星の磁気活動からE-mail contact: florian.gallet1 at univ-grenoble-alpes.fr星の年齢を見積もる方法（GyrochronologyやMagnetochronology）：
Age estimation techniques such as gyrochronology and magnetochronology cannot be applied to stars that have
- 近傍環境と角運動量を交換している星への適用は難しい
exchanged
angular momentum with their close environments. This is especially true for a massive close-in planetarycompanion(with a period of a few days or less) that could have been strongly impacted by the rotational evolution of- 特に近接大質量惑星（周期〜数日以下）を持つ場合、潮汐相互作用で恒星の自転進化への影響が大き

いため難しい
18

この論文

・経験的手法（この論文ではGyrochronology）において信頼できる範囲を探る
・恒星の角運動量進化コード ＋ 惑星軌道進化コード を使用- 恒星の表面回転速度の進化に、星-惑星潮汐相互作用が与える影響を詳細に調べる
結果

A&A proofs: manuscript no. aanda

黄色の領域：単独星より10%ほど自転が速い＝年齢測定で約20%の誤差
惑星質量が増えると、黄色の領域が右に広がる
Porbが4日以上だと適用可（1太陽質量、5木星質量の場合）

Fig. 1. Evolution of Prot,? (t) as a function of Porb (t) and stellar mass for a 2 Mjup (upper panel) and 5 Mjup (lower panel) planet. The color gradientcorresponds to the relative rotational departure Prot = 1 Prot,isol. /Prot,? . Only systems where the planet is still present are plotted. The blue lines(composed of plain circles) depict the evolution of a given star-planet system (Prot,init = 10.8 days and SMAinit = 30%Rco ) in the Prot,? (t) Porb (t)plane. The red area shows the domain of applicability of gyrochronology analysis.

A&A proofs: manuscript no. aanda

δProtが10%を超える継続時間Δt10%
vs. δProtが10%を超えるときの年齢
PMSの時（age < 100 Myr）にδProtが10%を超える
場合、星の質量が増えるとΔt10%は短くなる
近接大質量惑星と恒星の相互作用：

Fig. 2. Duration for which the surface rotation rate of a star in a star-planet system departs by more than 10% compared to the same but isolated
star (see sect. 3.1 for the definition of the variables). The black dots correspond to planets still orbiting the star, while the red dots are planets thathave been engulfed.

– Prot,isol.,x% is the rotation period of a star but without a planet

SuperWASP cluster data (Pollacco et al. 2006) in addition to theat the specific age Age . It is used as a comparison value to properties of the Hyades cluster
単独星よりも90%も自転周期が違う場合を考える：
quantitatively extract the impact of the presence of a massive
Age
= Age
⇤ (P
/P
)
Myr,
(5)
planet on the surface rotation rate of the stars.
x%–

tx% is the time during which the relative rotational departure Prot x%. For example, t0% corresponds to the time
it takes for a star to return to the rotational behavior of an
isolated star.
– Agegyro is the age estimated using a gyrochronology tool andbased on Prot,x% . It corresponds to the age estimated using theobserved stellar rotation period without information about
the rotational history.
– Agegyro,isol. is the “real” age of a star estimated using gyrochronology and based on Prot,isol.,x% . It corresponds to thetrue gyrochronologic age of a star that has never experienced
an impact of a planetary companion.

gyro

Hyadesrot,obs.

Hyades

1/0.56恒星の表面回転速度を大きく変える（たいていのケースで、惑星の飲み込みが関連）
several Gyrも若い見積もりに！

where the period-color relation in the Hyades is given byP= 10.603 + 12.314 ⇤ (J K 0.57) days,
表面自転周期における90%超の変化：~(6) a few 100 Myr 続くwith Age= 625 Myr. The (J-K )-mass relation is given by
the YREC isochrones extracted at 600 Myr for solar metallicity
stars (Z = 0.01757,
see An et al. 2007) .
10%の変化：~ a few Gyr 続く
Finally, gyrochronology analysis can only be applied to sysHyadess

Hyadess2

tems whose real age is older than about 100-200 Myr for a 1.0

M star and 500-600 Myr for a 0.6 M star (Barnes 2010; DeGyrochronology解析だと…
lorme et al. 2011).
We note that Ageand Ageare semi-synthetic ages
- they誤って若く見積もってしまうsince
are estimated using the rotation rate provided by the
Figure 1 shows the evolution of P (t) as a function of thegyro,isol.

gyro

numerical model and the gyrochronology tools calibrated on theobservations. The di↵erence between Agegyro,isol. and Agegyro
highlights the possible error on the age estimation that can be
introduced by the presence of a massive close-in planet. Moreover, in the case of a perfect age-Prot,? relationship, Agegyro,isol.
and Agex% should, by definition, be identical. However, since
Agex% is directly obtained from the stellar model STAREVOL,
while Agegyro is calibrated using observations, the two ages aredi↵erent (see Table 1).
In this article we used the gyrochronology calibration described in Delorme et al. (2011) that is slightly di↵erent fromthat proposed in Barnes (2003, 2007, 2010). In Delorme et al.
(2011) the calibration of the gyrochronology is done using the

3.2. Impact of tidal interaction on rotationrot,?

SMA(t) expressed in orbital period Porb (t), for the three stellar
masses (0.5, 0.7, and 1.0 M ), and the two planetary masses (2Mjup and 5 Mjup ) considered in this work. The relation between
SMA and Porb is given bys
SMA3
Porb = 2⇡.
(7)
G(M? + Mp )- 信頼性のある結果は得られない

Gyrochronologyと別の手法を組み合わせれば年齢推定のより良いツールとなる
The color gradient corresponds to the variation in P for eachが、自転進化は外部トルクの影響を強く受ける
pair [P (t) SMA(t) M
M ].
rot

rot,?

2

?

p

http://www.astronomy.ohio-state.edu/iso/empirical.html=> 新たな年齢測定手法の概念実証を提案：- tidal-chronology 法と呼ぶ

Article number, page 4 of 12- 恒星惑星系において観測される2つの値を使う
Prot,★：恒星の自転速度
Porb：惑星の位置（=公転周期）

F. Gallet and P. Delorme: Star-planet tidal interaction and the limits of gyrochronology

Tidal-chronology
1) 初期条件（Prot,init、SMAinit）からスタート
2) 星の初期自転速度と初期時t0での内部構造を仮定
し、星の散逸<D>ωを見積もる
3) <D>ωによって惑星の軌道進化が決まる
4) 惑星の軌道進化が星の自転速度を変える-> 1)に戻り、新たなProt, SMAinitから再スタート
Prot,★が増えるにつれ年齢も増える
この手法単体で年齢測定をするには、星惑星での潮汐散逸の描写が不十分
・惑星での散逸を考慮していない・星-惑星での磁場相互作用を考慮していない

Fig. 3. Synthetic Prot,? (t) and Porb (t) estimated for a system composed of a 0.5, 0.7, and 1.0 M star around which orbits a 2 Mjup planet (upper
panel) and a 5 Mjup planet (lower panel). Prot,init = 1-11 days (with Prot,init = 0.2 days) and SMAinit is between 0.1 and 1.0 Rco (Gallet et al. 2018).
The color gradient indicates the age (in Myr) at which the pair Prot,? (t) Porb (t) is extracted. Only planetary systems where the planet is still
orbiting the star are plotted. The blue lines (composed of plain circles) depict the evolution of a given star-planet system (Prot,init = 10.8 days andSMAinit = 30%Rco ) in the Prot,? (t) Porb (t) plane.

・radiative core内での散逸も物理的に描写していない星-惑星の磁場相互作用はPMSフェーズの間のみ存在するが、by the inward migration of the planet. The star-planet systemthus moves toward smaller SMA (Porb ) and rotation period (ifthe acceleration torque produced by the planet is stronger thanthe braking torque of the stellar winds or the PMS contraction
torque, see the blue tracks in Fig. 1).
The hypothesis of this paper implies that the orbit of theplanet is initially circular and coplanar, and remain so, with respect to the equator of the star during the whole stellar evolution.
The results above and the tidal-chronology technique are hence
only valid within this framework. Moreover, since we simply
present the proof of concept of such a technique, for now, thetidal-chronology should be used with caution and in addition toother age determination tools. In the future, and with the increasein the completeness and complexity of our tidal dissipation modeling, we hope that this technique will be reliable enough to derive reliable stellar ages by itself.
In this paper, and because of the nature of the tidal dissipation formalism we use, we only consider isolated star-planet
systems composed of one planet that orbits one star because themodel that we use does not allow us to follow the evolution ofmultiplanetary systems. Hence, we do not consider Kozai-Lidov
resonance (Kozai 1962; Lidov 1962), which is present in n-bodysystems (with n > 3) for a given body with an orbital inclination greater than 39 . Finally, we also mention the work of Wu& Lithwick (2011) on secular chaos in the evolution of the properties of almost coplanar multiplanetary systems. They pointed

MSフェーズでは別の散逸によりmigation timescaleが短くなり、見積もられる系の年齢を短くする
まとめ
Gyrochronologyが適用できるのは以下の場合のみ：
Fig. 4. Randomly selected P (t)-SMA(t) pairs (see text) with their- 単独星 もしくは
associated age dispersion (tt )/t .
rot,?

max

min

min

- Prot,★-Porbの特定範囲外にある星惑星系
恒星と惑星の質量が大きいほど広くなる(tmax tmin )/tmin associated with each of these pairs and plot themin Fig. 4.
In the case of migrating planets, the evolution of star-planet
systems in the Prot,? (t)-Porb (t) space depends on their initial conditions. As the star evolves, its surface rotation rate is impacted

禁じられた範囲 or 惑星の飲み込みが疑わしい場合： Gyrochronologyは特別な注意を払って使用すべき

Article number, page 7 of 12

Tidal-chronologyは今のところ、系の正確な年齢は与えない

V. Getman,1? E. D. Feigelson,1 M. A. Kuhn,2 G. P. Garmire3

rtment of Astronomy & Astrophysics, 525 Davey Laboratory, Pennsylvania State University, University Park PA 16802
rtment of Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
ingdon Institute for X-ray Astronomy, LLC, 10677 Franks Road, Huntingdon, PA 16652, USA

18 Gaia Stellar Kinematics in the Head of the Orion A Cloud:Runaway Stellar Groups and Gravitational Infall

ed for publication in MNRAS; 05/23/19

K. V. Getman,1? E. D. Feigelson,1 M. A. Kuhn,2 G. P. Garmire3

1 Department of Astronomy & Astrophysics, 525 Davey Laboratory, Pennsylvania State University, University Park PA 16802
2 Department of Astronomy, California Institute of Technology, Pasadena, CA 91125, USA

ABSTRACT

Xiv:1905.03844v1 [astro-ph.SR] 9 May 2019arXiv:1905.10251v1 [astro-ph.GA] 24 May 2019

3 Huntingdon Institute for X-ray Astronomy, LLC, 10677 Franks Road, Huntingdon, PA 16652, USA

19This work extends previous kinematic studies of young stars in the Head of the Orion
A cloud (OMC-1/2/3/4/5). It is based on large samples of infrared, optical, and XAccepted for
publication
in MNRAS;
05/23/19
ray
selected
pre-mainsequence stars with reliable radial velocities and Gaia-derived
parallaxes and proper motions. Stellar kinematic groups are identified assuming they
mimic the motion of their parental gas. Several groups are found to have peculiar
ABSTRACT
kinematics: the NGC
two kinematic
stellar groups
inoftheExtended
NebulaThis1977
work cluster
extends andprevious
studiesyoung
stars in Orion
the Headof the Orion
Draft
May
13,
2019
(EON)version
cavity arein the act of departing
birthplaces.
The abnormal
A caught
cloud (OMC-1/2/3/4/5).
It is based theiron large
samples of infrared,
optical, and XA
Typesetusing
L
TX
modernstyle
inAASTeX62
motion of NGC E1977
may havebeensequencecaused stars
by awith
globalhierarchicalcloud andcollapse,
ray selected
pre-mainreliableradial velocities
Gaia-derived
parallaxes
and propermotions.
Stellar kinematicgroupsare identified
assuming they
feedback by massive
Ori OB1abstars,
supersonicturbulence,
cloud-cloud
collision,
mimic thetheir
parental
Severalbygroups
are foundto might
have peculiar
and/or slingshot e↵ect;the motion
formeroftwo
modelsaregas.
favoredus. EON
groupskinematics:
the NGCand twostellar groups
the Extended‘rocket
Orion Nebula
have inherited anomalous
motionsof1977theircluster
parental
cloudlets
due toinsmall-scale(EON) cavity are caught in the act of departing their birthplaces. The abnormale↵ects’ from nearby
OB ofstars.
sparsestellargroupsto the east
andmotionNGCWe
1977also
mayidentify
have beencausedby a global
hierarchicalcloudcollapse,west of Orion A thatare driftingfromthecentralregion,possiblya slowly
expanding
feedbackbymassiveOri
OB1abstars,
supersonicturbulence,
cloud-cloud
collision,
Modelling
SpatialDistribution
andOrigin areof favored
CO findings
Gas
in of
DebrisDisks
halo ofthe Orion the
NebulaCluster.
We theconfirm
varying
and/orslingshote↵ect;
formerpreviously
two modelsreported
by us. EON
groups might
1,
2
3,
4
1,
2
5 and
have
inheritedanomalous
motionsof
theirparental
cloudletsdue
tosmall-scale‘rocketline-of-sightdistancestodi↵erent
parts
of
the
cloud’sHeadwithassociateddi↵erences
Hales,
Uma
Gorti,
John M. Carpenter,
Meredith Hughes,
DraftA.S.
versionMay 13,2019e↵ects’ from nearby movies
OB stars.
identify
sparsegroups tooftheeast andin gas velocity. Three-dimensionalof We
staralso
kinematics
showstellar
contraction
the
6,
5
Kevin
Flaherty
Typesetgroups
using of
LATstarsstyle
AASTeX62
of OrionAin
that
are driftingfrom theregion,stars.
possiblya slowly the
expanding
EX moderninwestOMC-1
andglobalcontraction
ofcentral
OMC-123
Overall,halo of the Orion Nebula Cluster. We confirm previously reported findings of varying
1
Joint of
ALMA
AvenidaAlonsodeCórdova
3107,
Vitacura
7630355,
Santiago,
Chile
Head
OrionObservatory,
A line-of-sight
region exhibits
complexmotions
consistentwiththeoreticalmodelsdistances to di↵erent parts of the cloud’s Head with associated di↵erences2
involvingcollapse(possibly
turbulent)cloudswith
National hierarchicalRadio Astronomy
Observatory,
520in
Edgemont
Charlottesville,
VA OB
22903-2475,
in gasgravitational
velocity.
Three-dimensional
moviesof Road,star
kinematics
show contractionof theUnited andStatesof America
stellar feedback. groups of stars in OMC-1
globalcontraction of OMC-123 stars. Overall, the3
Headof OrionA region
exhibits
complexmotions consistenttheoretical models
NASA
Ames
ResearchCenter,MS
245-3,
Mo↵ettField, andCAwith
94035-1000
Key words: infrared:stars–
stars:
early-type–
openclusters
associations:involving4hierarchical gravitational collapse in (possibly turbulent) clouds with OB
SETI
Institute,
Mountain
View,
CA
94043
general–stars:
formation–stars:
pre-mainsequence–
X-rays:stars
stellar feedback.
Modelling
the Spatial
Distribution and Origin of CO Gas in Debris Disks
5
Wesleyan University, Van Vleck Observatory, 96 Foss Hill Dr, Middletown, CT 06459
Key
words:
stars – stars: early-type1,–2 open clusters and associations:3, 4infrared:
5
6
A.S. Hales,1, 2 Uma
Gorti,John
M.
Carpenter,
Meredith
Departmentof Astronomy
and Department
Physics
general– stars: formation– stars:
pre-mainsequence –of
X-rays:stars Hughes, and6,
5
WilliamsKevin
College, Flaherty
Williamstown, MA 01267 USA

v1 [astro-ph.SR] 9 May 2019

NTRODUCTION1

proposed to play major roles in the formation of both the

Joint ALMA Observatory, Avenidasub-filaments
Alonso de Córdova
3107,filaments
Vitacura(e.g.,
7630355,
Chileand integrated
Smith Santiago,
et al.
ABSTRACT
bubbles, and filamentary
molecular cloud structures
1 2INTRODUCTION
proposed to et
play
roles
in theformation
both theNational
Radio Astronomy Observatory,
520
Edgemont
Road,
Charlottesville,
VA of22903-2475,
2016; Vázquez-Semadeni
al.major
2019).
Dense,
gravitationallyiquitous in the Galaxy (Churchwell et al. 2006; André
sub-filaments
and integrated filaments (e.g., Smith et al.
UnitedStatesofAmericabound
pre-stellar
cores
then
form by cloudfragmentation
Shells, bubbles,andfilamentary molecular
structuresThe
detectionof gas cloudin debrisdisksraisesthequestionwhether
this gas is a2016;
Vázquez-Semadeni
et al. of2019).
Dense, gravitationally2014) and are often sites of starformation.
Hierarchicalare ubiquitous in 3
theGalaxyAmes(Churchwell
et al. 2006;
André
along
the MS
densestfilaments;
core
growththroughfilamenNASA
ResearchCenter,245-3,
Mo↵ettField,
CA
94035-1000
bound pre-stellar
cores
then
form by bycloudthefragmentation
entation in molecularcloud
filaments
is
often
observed
remnantfromtheprimordial
protoplanetaryphase,
orreleasedcollision of
et al. 2014) and are often sites of star formation.
Hierarchicaltary accretionis alsoreported(Andréet al.
2014).
Small
4
along
the
densestCA
filaments;
growththroughfilamenSETI
Institute,
Mountain
View,
94043coreles ranging from fragmentation
several parsecs
to <
0.1
pc.
Di↵erin molecularcloud
filaments
is
often
observed⇠bodies. In this paper
star clusters
mayin isthesecores
through
formasecondary
we analyze
ALMA
observations
atstartaryemerge
accretionalso
reported(Andréet1-1.5”al.
2014).resolution
Smallhysical mechanisms
to trigger
the cloudfragon appear
scales5 Wesleyan
rangingfrom University,
severalparsecs
to <
0.1
pc.
Di↵erVan
Vleck
Observatory,
96
Foss
Hill
Dr,
Middletown,
CT
06459
⇠
star
maycoreemergein these cores
throughstar formation mediatedby clusters
turbulentaccretion(McKee& Tan
12ent
physicalmechanisms
appeartotriggerthecloudfragofthree
debris
disks
where
the
CO(2-1)
rotationalline
wasdetected:
HD
131835,tion including gravitational collapse; thermal,
turbu6tion
mediatedbyturbulentcore
accretion(McKeeDepartmentofAstronomy
andaccretion
Department
ofetPhysics
2003),
competitive(Bonnellal. 2001;
Wang
et al. & Tan
mentation
includinggravitational
collapse;thermal,turbund magnetic pressures;
angularmomentum;anddy2003),competitive
accretion(Bonnell
et
al.
2001;
Wang
et
al.
138813,andHD
156623.
Wedyapply
the iterative
Lucy-Richardson
deconvolution2010),
stellarmergers(BonnellBate USA
2005), and/or global
andHD
magneticpressures;
angularmomentum;andWilliams
College,
Williamstown,
MA &
01267
2010), stellar mergers (Bonnell & Bate 2005), and/or global
al feedback from lent,
youngstellaroutflows,
winds,
andhierarchicalcollapse(Vázquez-Semadeni
et al.
namical feedback
from toyoung
stellaroutflows,ofwinds,
and gravitational
techniquetheet
problemcircumstellar
disks gravitational
toderivedisk geometries
andetsurface
hierarchicalcollapse(Vázquez-Semadeni
al.
ion pressure (Takahashi
al. 2013;
Contreras
al. Contreras
radiationetpressure(Takahashial.et2013;al.
2017,et2019).
Molecular
gasMolecular
can thengas
becan
expelled
feedback
2017, 2019).
then be byexpelledby feedback
Teixeira et al. 2016).
It
is
also
possiblethat
cloudsare
2016; Teixeira
et al. 2016).
It is also possible ofthate↵ects
cloudsarebrightness
distributions
the
gas.
The
deriveddisk
parameters
are
used
as
ABSTRACTof young
starsof including
ionizing
and andinpute↵ectsyoung starsOB
including
OB radiation
ionizing radiation
y composed of velocity-coherent(Hacarlargely composed sub-filamentsof velocity-coherent
sub-filaments (Hacar
winds,
supernovae,
protostellar
accretion
heating,
protostelwinds,
supernovae,
protostellar
accretion
heating,
protostelfordetection
thermochemical
modelsto disks
test
primordialand cometaryscenarios
for theet al.
2013,2018).
Turbulentor global
hi- both
2013, 2018). Turbulent
energycascadesor
globalhiTheofenergy
gas cascadesindebrisraisestheoutflows
questionof whether
this gasis a
lar jets (Daleandlar jetsand outflows2015).(Dale 2015).
erarchicalgravitational
collapseenhancinganisotropies
areical gravitational collapseorigin
enhancinganisotropiesof thegas. Wearefavor a secondary origin for the gas in these disks and find thatremnant from the primordial protoplanetaryphase,
orreleasedbythecollisionof
A and B giant molecular filaments are the
A The
and Orion
B giant
molecular filaments are the7
the CO gas masses (⇠ 3 ⇥ 10 3The
M Orion) require(⇠active5 ⇥ 10M yr 1 )two mostproduction
prominent sitesrates
of recentstar formation
two most prominent
sites
recentactivebodies.
ALMA
observations
at formation
1-1.5”? secondary
E-mail: kug1@psu.edu(KVG) In this paper we analyze(Megeath
et al. of2012;
Meingast
et al.star
2016)
within theresolution
nearbyrich
disk
ail: kug1@psu.edu (KVG) similar to those estimated for(Megeath
et al. 2012; gas
Meingast
etdebrisal. 2016)
within Pic.
the nearby
12the bona-fide

8 The Authorsof three debris disks where the CO(2-1) rotational line was detected: HD 131835,
HD 138813,
andopenHDclusters
156623.and
Weassociations:apply the iterative
deconvolution
Keywords:
individualLucy-Richardson(Scorpius Centaurus)— planetechnique to thetary
problemof circumstellar disks to derive disk geometries and surface
systemsbrightness distributions of the gas. The derived disk parameters are used as input

c 2018 The Authors

K. Hayashi,1 R. Okamoto,1 H. Yamamoto,1 T. Hayakawa,1 K. Tachihara,1 and Y. Fukui2, 1
1

Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
21 InstituteGas and
Dust Properties
in theUniversity,
Chamaeleon
Molecular
Cloud
Complexbased
onsano@a.phys.nagoya-u.ac.jp
the Optically Thick H i
for Advanced
Research, Nagoya
Furo-cho,Chikusa-ku,
Nagoya464-8601,
Japan;

arXiv:1905.04184v1
10 May102019
May 2019[astro-ph.GA]
8 May [astro-ph.GA]
2019 [astro-ph.GA]
1.03230v1[astro-ph.GA]
8arXiv:1905.04184v1
May 2019

2

K. Hayashi,1 R. Okamoto,1 H. Yamamoto,1 T. Hayakawa,1 K. Tachihara,1 and Y. Fukui2, 1(Accepted May 8, 2019)
1 Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
2 Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan; sano@a.phys.nagoya-u.ac.jp

ABSTRACTGas and dust properties in the Chamaeleon molecular cloud complex have been investigated with(Accepted May 8, 2019)
emission lines from atomic hydrogen (H i) and 12 CO molecule, dust optical depth at 353 GHz (⌧353 ),and J-band infrared extinction (AJ ). We have found a scatter correlation between the H i integrated
ABSTRACTintensity (WH i ) and ⌧353 in the Chamaeleon region.
The scattering has been examined in terms of
Gas anddust
properties
theChamaeleon
cloud
complexhave
investigatedpossiblelarge
opticaldepth in Hi emission(⌧H i ) molecularusing a total
columndensity(Nbeenbased on withH ) model
12
emissionlines fromatomic(Hi)
andCOmolecule,
dust
optical
depth
at
353
GHz
(⌧353 ),
⌧353 . A nonlinear
relationof ⌧hydrogen
with
the
⇠1.2
power
of
A
has
been
found
in
opaqueregions(A
353
J
J & 0.3
mag),which infrared
may indicate
dust evolutione↵ect.
we applythis nonlinear
relationto theandJ-bandextinction(AJ ). We
have Iffounda scattercorrelation
betweenthe NHHi model
integrated
1/1.2
intensity⌧353 in the
Chamaeleon
The scatteringterms of(i.e., NH (W/ H⌧353) allowing
arbitrary⌧H i , theregion.
model curve
reproduceshas
wellbeen
the examined
WH i –⌧353 inscatteri ) andcorrelation,suggesting
opticallythick
H i (⌧H i(⌧⇠1.3)
extendedaroundthedensity
molecular
possiblelarge
optical depthin H
i emission
a totalcolumn(NHclouds.
) modelBasedbased onH i ) using
Draft version May 9, 2019
thebetweentheintegrated
thenderived⌧on. Acorrelations
nonlinear
relation⌧353COwiththe ⇠1.2intensity
power ofand
AJ thehasNbeenfoundwein have
opaqueregions(Athe
H model,353
J & 0.3
AT X default
Typesetusing
Lstyle in of
AASTeX62
E
CO-to-Hfactor dust
(XCOevolution) on ⇠1.5e↵ect.
scalesIf(corresponding⇠4 persec)
and found
2 conversion
mag),
which
may indicate
we apply this tononlinear
relationto thespatial
NH model20
1
1/1.2
variationsof X
cm 2 K ⌧ 1 kms across the cloud complex, possibly depending on
CO ⇠(0.5–3)⇥10(i.e.,NH /⌧353) allowing arbitrary
H i , the model curve reproduces well the WH i –⌧353 scattertheradiation
field
insideorsurroundingthemolecular
clouds. These
gastheproperties
foundin thecorrelation, suggesting optically thick H i (⌧H i ⇠1.3) extended
aroundmolecular
clouds.
Based
Chamaeleon
regionarediscussed
througha
comparison
with
other
local
molecular
cloud
complexes.
APEX
Millimeter
ObservationsofMethanol
Emission
TowardHigh-Mass
Star-FormingCoreson the correlations between the CO integrated intensity and the NH model, we have then derived theDraftversion May
9, 2019 factor (X1, ∗CO ) on ⇠1.5 1 scales (corresponding†
2
3
CO-to-Hto ⇠4persec) 2,and
foundGaray,
spatial2 conversion
Vicenteández-Hernández,Stan Kurtz,
SergeiKalenskii,
PolinaGolysheva,
TypesetusingHernLATEISM:X
default
style—in ISM:
AASTeX62
Keywords:
atoms
individual(Chamaeleon
Molecular
Cloud)— ISM: Guido
molecules
20
2 objects
1 1
14variations of XCO ⇠(0.5–3)⇥10 Luis
cm Zapata,
K km
acrossthe cloud complex, possibly depending on
and sPer
Bergmantheradiation
field
insideorsurroundingthemolecular
clouds.
gas properties found in the
1 Instituto de Radioastronomı́a y Astrofı́sica, Universidad Nacional Autónoma de México,These
Apdo. Postal 3–72 (Xangari), 58090 Morelia,
Chamaeleon region are discussed through Michoacán,a comparison
with
other
local
molecular
cloud complexes.
México22

2 Astro Space Center, Lebedev Physical Institute, Russian Academy of Sciences
APEX Millimeter
Observations of Methanol
Emission Toward High-Mass Star-Forming Cores
1. INTRODUCTION

3 Departamento de Astronomı́a, Universidad de Chile, Camino del Observatorio 1515, Las Condes, Santiago, Chile
1, ∗
1
2
2, †

Keywords: ISM: atoms — ISM: individual objects (Chamaeleon Molecular Cloud) — ISM: molecules
3

4VicenteHernández-Hernández, andStan
Kurtz,
Kalenskii,
PolinaGuido
Garay,
The
neutralhydrogenon theatomicmolecular
occupies
majorSpace
massof Golysheva,
the interstellar
medium(ISM)
Deptof Space,
EarthandEnvironment,
Chalmers
Univ.forms
ofSergei
Technology,
OnsalaObservatory,
SE-43992
Onsala,Sweden and
1
4
Luis
Zapata,andPer
Bergmanis a fundamental constituent of the ISM. In the electronic ground state neutral atomic hydrogen (H i) has two spin
1 Instituto
stateswhere
the spin angularmomenta Universidadof a protonNacionalandan Autónoma
electron areparallelApdo.
or anti-parallel.
The energy
separation
ABSTRACTde Radioastronomı́ay Astrofı́sica,de México,
Postal 3–72 (Xangari),
58090
Morelia,
6
Michoacán,Méxicobetween thetwostates
is
small
(5.9
⇥
10
eV)
and
corresponds
toawavelength
of
21
cm.
The
21
cm
H
i
transition
We present 247-GHz
molecular line observationsof methanol (CH3 OH) toward sixteen massive star2 Astro Space Center, Lebedev
1.Physical
INTRODUCTION
Institute, that
Russianof is
Sciences′′completely optically thin (e.g.,
is used toforming
calculate
H i column
density(NH itelescope) usually
by assuming
theAcademy
emission
regions,
using
the
APEX
with
an
angular resolutionof 25. The sample covers a
3 Departamentode Astronomı́a, Universidad de Chile, Camino del Observatorio 1515, Las Condes, Santiago, Chile
The4 neutralhydrogenon thestates,
atomicincluding
and molecularforms occupies
major
mass ofcores,
the interstellar
medium (ISM) andBoulanger& Perault
1988).
range
ofevolutionarywarm
molecularcores,
hot
molecular
and ultracompact
Dept of Space, Earth and Environment, Chalmers Univ. of Technology, Onsala Space Observatory, SE-43992
Onsala, Swedeninterstellar
H i Thegas, hothowever,temperature
range
over
order
ofhydrogenmagnitude:
is spinis aThefundamental
constituent
ofcores,the has
ISM.
theandelectronic
state
neutralatomic(H i)density
has two
HII regions.
all density
of In
which
includeUCgroundHII whichregions,show
richmolecularline spectra,
33
34
distributed
from
1
cm
to
10
cm
and
temperature
from
10
K
to
10
K
(e.g.,
Draine2011).
The
gas
consistsofstates
where
the
spin
angularmomentaofaprotonandanelectronareparalleloranti-parallel.
The
energyseparation
although the strength of diﬀerent species andABSTRACT
transitions varies from source to source. In contrast, the6 (CNM) and the warm neutral medium (WNM). The CNM is dense andtwo distinct
phases,thenotcold
neutralbetweenthetwostatesis
small(5.9 medium⇥ 10 moleculareV) andline
corresponds
to a wavelength
21 cm. The
cm H i transition
warm
cores
do
show
significant
emission. Multiple
methanoloftransitionsare 21detected
We present
247-GHz
molecularline observations
ofwarmmethanol(CH
towardsixteenmassive
star3
3
3 OH)
(⇠30
cm
and
⇠60
K),
while
the
WNM
is
di↵use
and
(⇠0.6
cm
and
⇠2000
K)
(e.g.,
Heiles& Troland
iscoolused
totoward
calculateHicolumndensity(N)
usuallybyassuming
that
theemissioniscompletely
optically
thin (e.g.,nine of the hot cores; eight ofdiagram method
H i these had enough transitions to use the rotation
forming
regions,using
theisAPEX
telescopewithanangularbecause
resolutionof25′′ . The sample
coversa
2003b; Draine2011).
TheHi
gas
highlyturbulentandtransientit
iscontinuously
shockedbysupernovae
Boulanger&
Perault1988).
to estimate rotational temperatures and column densities. The temperatures lie in the range 104–168
rangeyear.
of evolutionary states, including
warm molecularcores, hot molecular cores, and ultracompact
16
every
K and
columndensities
from 3has
× 10
to 7 and× 1018cm−2 . Usingwhich
the average
parameters,
The million
interstellar
H i Thegas,
however,
densitytemperature
range methanol
overorderline
oflinemagnitude:
density is
HII
regions.
hotcores,
allofwhich
includeUC
HII
regions,
show richmolecular
spectra,To measure
precisely
local
i 3gas
with
ofto
the
depth,
Fukui
et al.
(2014,
2015) of
3themasses,
3 Hwhich
4opticalwe fromestimate
virialfallin thethe large
range variations
from 145
to
720
M
and
provedto 2011).
be significantly
distributed
1
cm
to
10
cm
and
temperature
from
10
K
10
K
(e.g.,
DraineThegas
consists⊙
althoughthe proposed
strength of
speciesand transitions
variesfrom
sourcedepth
to source.
In GHzcontrast,the(hereafter
F14,
F15)
a diﬀerent
methodtocalculate
Nand
based
on
dust
opticalatchemical
353
(⌧CNM
is andH ipossible
353 ), whichhigherthanthemeasuredgas medium
masses.
We
discuss
scenarios
toexplainthediﬀerencestwo
distinctphases,thenotcold
neutral(CNM)
the warm
neutralmedium(WNM).
The
is dense
warm
cores
do
show
significant
molecularlineemission.
Multiplemethanoltransitionsaredetected+
estimatedbetween
from3modified
black
body
spectrafittedtothefluxesat
submillimeter
wavelengths
measuredbythePlanck3
hot of
cores
and
warm
molecularcores.
Oneof theobservedmethanollines,
42 −5
atmethod247.228
1 A (e.g.,cool (⇠30toward
cm nine
and
⇠60
while
is di↵use
and
warm
(⇠0.6
⇠2000
K)
Heiles & TrolandtheK),
hotcores; theeightWNM
of theseenoughtransitions
to cm
use
theandrotation
diagram3
and IRAS
satellites(Planck
Collaboration
2014a).
⌧had
tointensity
be verysmall
inthe orderof ⇠10
towardthe353 is measuredGHz,ispredicted
to
show
class
II
maser
emission,
similarintopreviously
reportedJ−J, −1
E supernovae0
2003b; Draine2011).
The
H
i
gas
is
highlyturbulentandtransientbecauseitiscontinuously
shockedbytoestimate
rotationaltemperatures
andcolumndensities.
Thegastemperatureslieisinuniform.
the range
104–168
Galactic masers
mid
plane
and
we
are
able
to
use
⌧
as
a
tracer
of
N
if
the
to
dust
ratio
The
results
of
F14
353
H
i
at 157 GHz.
We did
not ×
find
any
clear
evidence
maser emission
among the observed
sources;18
every million
year.
K
and
densities
from
1016
tocan
7 ×be
10
cm−2for. Usingaveragelinelowparameters,
and F15 however,give
a column
suggestionthat theH i3 line
emission
optically
thick thein theordermethanolof 1.0 withspin temperature
a
weak
maser
in
this
may
exist
in
G345.01+1.79.
To measure
precisely the
local which
H i gasfallwith
therange
largefromvariationsof thedepth,beFukui
et al. (2014, 2015)
weK)
estimate
masses,theto 720M⊙ opticaland proved
significantly(Ts . 100and thevirial
considerable
amount ofinatomic
hydrogen145
is underestimatedby the tooptically
thin assumption
higherthanthemeasuredgasmasses.
We
discussNpossible
scenarios
to opticalexplain depth
the chemical
diﬀerences(hereafter
F14,
F15)
proposedamethodtocalculate
based
on
dust
at
353
GHz
(⌧353 ), which isHioften adopted in studies
of formation
the local ISM.
+
–spectra
ISM: molecules–thestars:– methanolstars: protostars
masersbetweenhotstars:coresblack
and warm
cores.toOne
offluxes
themassive
observedlines,
42–−5
at 247.228by the Planck
estimatedKeywords:
from modified
bodymolecular
fittedat submillimeter
wavelengths
1 A measured
is predicted
to Collaboration
show class II maser
emission,in intensity
to previously
reported
J−1 E3 , toward the0 −⇠10and IRASGHz,
satellites(Planck
2014a).
⌧353 issimilar
measured
to be verysmall in theorderJof

arXiv:1905.01901v1 [astro-ph.GA] 6 May 201
arXiv:1905.01901v1 [astro-ph.GA] 6 May 2019

3 Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa, Italy

Efficiency of Explosion Chemistry As A Source of Complex Organic Molecules in TMC-1
23 Investigating the(Received
January
2018; Revised January
2018;
Accepted
7, 2019)
Preprint
31 May1,2019
Compiled 7,
using
MNRAS
LATEX Maystyle filev3.0

00, 1–27 (2019)

Jonathan Holdship,1 Jonathan Rawlings,1 Serena Viti,1 Nadia Balucani,2 Dimitrios Skouteris,3 and1Submitted
to ApJDavid Williams
1 Department of Physics & Astronomy, University College London, Gower Street, London, WC1E 6BT

Dipartimento
di Chimica, Universita‘
Perugia,Via Elce di Sotto, 8 I-06123 Perugia, Italy
Milky Way Project
SecondDatadiABSTRACT
Release:Many species of complex
organicSuperiore,molecules(COMs)
have 7,been
observedin several astrophysicalScuola Normale
Piazzadei Cavalieri
I-56126
Pisa, Italy
bles andenvironments
Bow Shocks
but it is not clear how they are produced, particularly in cold, quiescent regions. One
23.12625v1 [astro-ph.GA] 28 May 2019

(Received
January
2018; Revised
January
2018; Accepted
May 7,of2019)
process that has been
proposedas 1,
a means
to enhance
the7,chemicalcomplexity
the gas phase in suchregionsistheexplosion
of
the
ice
mantlesof
dust
grains.
In
thisprocess,
a
build
up
of
Submitted to ApJ1,6
1,2,3? , Don Dixon1,4,5 , Matthew
1 , chemical energy
du Jayasinghe
S.
Povich,Breanna
Binderin the ice is released, sublimating the ices and producing a short lived phase of high density, high1
1 ,gas-grain
7 , Stella
7 , Henry
temperaturegas. Thechemicalcode
UCLCHEMhas been
to treat8 ,these explosions
elasco , Denise
M. Lepore
Duo XuO↵ner
A.modified
Kobulnicky
ABSTRACT
in ordertospecies
modeloftheobserved
abundancesof (COMs)
towards
theobserved
TMC-1 inregion.
is found that,
9Many
10 , organic
complexmolecules
have11been
severalItastrophysicalD. Anderson, SarahKendrew
andRobertJ.COMsSimpson
based
on
our
current
understandingofthe
explosionmechanism
andchemicalpathways,theent of Physics and Astronomy,
California
Polytechnic
University
Pomona,3801 West
Temple Avenue,
PomonaCA 91768,
USAinclusion
environments
but itStateis notclear howthey areproduced,particularly
in cold,
quiescentregions.
One
ent of Astronomy,
The
Ohio
State
University,
140
West
18th
Avenue,Columbus,OH
43210,
USAof process
explosionsinchemicalmodelsisnotwarranted
at
this
time.
Explosions
are
not
shown
to
improvethat has been proposed as a means to enhance the chemical complexity of the gas phase in suchther Cosmology and Astroparticle Physics, The Ohio State University, 191 W. Woodru↵ Avenue, Columbus, OH 43210, USAmodel’smatch
the observed
abundancesofdustsimplespeciesin
TMC-1.
the energy
inclusion
regions
the toexplosionof the6301
ice
mantlesgrains.
In thisaFurther,build up neitherof chemicalt University, Department
of isPhysics
and Astronomy,
Stevensonof
centreLane,
Nashville
TN,process,37235, USAA
000,ice
1–27(2019)
May
2019
using
MNRAS
L TEofXphasestyle
file v3.0
ofMNRASsurfacedi↵usion
norPreprint
explosions,
results
inCompiled
the aproductionCOMs
observationallyinisreleased,
sublimating
the31TNices
andproducing
short
lived
of withhigh density,highversity, Departmentof thePhysics,
1000
17thchemistry,
AvenueN., Nashville,
37208,USA
n Astronomy, California
Instituteofgas.
Technology,
Pasadena,
CA 91125,
USAUCLCHEM has been modified to treat these explosions
inferredabundances.
temperature
The gas-grainchemicalcode
ent of Astronomy, The University of Texas at Austin, Austin, TX 78712, USA
in order to model the observed abundances of COMs towards the TMC-1 region. It is found that,ent of Physics & Astronomy, University of Wyoming, Dept 3905, Laramie, WY 82070-1000, USA
The
Way
Project
SecondData Release:
Data
and Processes:
molecules—
ISM: dustthe inclusion
25andKeywords:
basedMilky
on Physicalourunderstandingof theastrochemistry—
explosion
chemical pathways,
ent of Physics
Astronomy,
Westcurrent
Virginia
University,
Morgantown,
WV 26506,mechanism
USA ISM:andn Space Agency, Space
Telescope andScience
Institute,
3700 San
MartinDrive, Baltimore
MD 21218,
USA
Bubbles
Bow
Shocksof explosions
in chemical
modelsis notwarranted
at this time.
Explosions
are not shown to improve theAstrophysics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK
model’s1.match
to the observed abundances of simple species
TMC-1.
neither the
inclusion
INTRODUCTION
modelsinusing
gas Further,phase reactions
to form
glycolaldehyde
1,2,3?
1,4,5
1,6
1
of
surfacedi↵usionchemistry,nor
explosions,
results
intheproduction
of
COMs
with
observationally(HCOCH
OH)
can
match
the
abundances
observed inTharindu
Jayasinghe, Don Dixon, Matthew S. Povich ,2 Breanna Binder ,Complex
Organic
Molecules (COMs)
are organic
inferredabundances.
1 , Denise
8 , 2018). Recent observations
hot7 ,corinos
et al.
XXX. Received
YYY;
in Velasco
original
form
ZZZ atoms,
Jose
M. LeporeDuo
Xu7 , Stella
O↵ner
Henry (Skouteris
A. Kobulnicky
molecules
with
six ormore
over1 , 50
species
of
9
10
11
of
formamide
towards
theL1157-B1
shocked region were
Loren
D. detectedAnderson in, SarahKendrew, andRobert J. Simpson
which havebeen
the and
ISM(Herbst&van
1 Department
Keywords:
Physical
Data
Processes:
astrochemistry—
ISM:
molecules—
ISM:
dust
of Physics
and Astronomy,
California
State Polytechnic
University Pomona,
3801
West
TempleAvenue,PomonaCA
91768,
USA
also well fit by shock models in which the parent species
Dishoeck 22009).
Understanding
that18thleads
Departmentof Astronomy, The Ohiothe
State chemistry
University, 140 West
Avenue, Columbus, OH 43210, USA
ABSTRACT
3 Centre for Cosmology and Astroparticle Physics, The Ohio State University, 191 W. Woodru↵ Avenue, Columbus, OH 43210, USA
werereleasedinto
the gas patphase by the shock passage
4 Vanderbilt
to the formationof 1.suchlargehasmolecules
isAstronomy,an active
area throughCitizenscience
astronomers
comb
large
data
sets
to identify
University,
Departmentof helped
Physics and6301 Stevenson
centre Lane,
Nashville
TN, 37235,
USA
INTRODUCTION
modelsusing
gas phasereactions to form glycolaldehyde
5 Fisk University, Department of Physics, 1000 17th Avenue N., Nashville, TN 37208, USA
then reacted
inThe
theMilky
warm, dense post-shock gas
terns andlaboratory
objects thatexperiments
are not easily(Chuang
found through andautomated
processes.
of research
including
6 Visitorin Astronomy, California Institute of Technology, Pasadena, CA 91125, USA (HCOCH2 OH) can match the abundances observed inComplex
Organic
Molecules(COMs)
areorganic
7 Department
Way
Project(MWP),
acitizenscienceinitiativeontheZooniverse
platform,
presents(Codellaetal.
2017).
Similarly,
Kahane et al. (2013)of Astronomy,at Austin, Austin,surTX 78712, USA
et al. 2016;
Bergantini
et Theal.University2017),of Texas
observationalhotcorinos(Skouteris
et al.plane2018). Recent observations
8 Department of Physics & Astronomy, University of Wyoming, Dept 3905, Laramie, WY
82070-1000,
USA
molecules
with
six
or
more
atoms,
over50
speciesofinternetusers
withinfrared(IR)
imagesfrom
SpitzerSpace
Telescope
Galactic
foundthat observed formamide abundances in the pro9 Department of Physics and Astronomy, West Virginia University, Morgantown, WV 26506,
USA
veys(Ceccarelli
et al. MWP
2017; inBellocheetal. classification
2016),
andof formamide
towards
the L1157-B1
shocked region weresurveys.
makeonMDtheimagesto identify
tar10 European
which havebeen
the Science
ISM(Herbst& Martinvan drawings
Space detected
Agency, Spacevolunteers
Telescope
Institute,
3700 San
Drive, Baltimore
21218,
USA
tostarIRAS
16293-2422
could
be thereproduced
using a11 Oxford
modellingwork(eg.
Coutensetal.
2018).
However,the
Astrophysics,
Denys
Wilkinson
Building,
Keble
Road,
Oxford
OX1
3RH,
UK
also
well
fit
by
shock
modelsinwhichparent species
getedUnderstandingclasses of astronomical
objects.
Weleads
present the MWP second data release (DR2)
Dishoeck 2009).
the chemistry
that
model
that
assumedparentspeciesable toandroutes
an updated
datainreduction
pipeline
written in werePython.
We aggregate⇠3
released
into theneutral
gasmillion
phaseby theshockwerepassagemajor
formationof large
COMs
star forming
regions
to theformationof suchmolecules
is an active
area
react
in
the
warm
gas.
classifications
made
by
MWP
volunteers
duringtheyears
2012–2017
toproducetheAccepted
XXX.
Received YYY; in original form ZZZ
and then reacted in the warm, dense post-shock gas
remainsanopenquestion.
of research
includinglaboratory
experiments
DR2
catalogue,
which contains
2600(Chuang
IR bubbles and(Codella599
candidatedriving
Alternatively,
COMsSimilarly,
inthe gasKahane
phase may
best exet al. bow-shock2017).
et al.be(2013)
Itet isal.possible
that
COMs
form
in thegas phasesurof as assessed
2016; stars.
Bergantini
et al.
2017),
observationalThe
reliabilityofbubbleidentifications,bycomparison
tovisualidenplainedbygrain
surfaceformation
followed
by
ABSTRACT
found that observed
formamide
abundances in the desorpprostar
forming
regions.
For
example,models
have
shown
veys
(Ceccarelli
et al.
2017;
Bellocheethasal.helped2016),
andtifications
bytrainedexpertsandscoringby a machine-learningalgorithm,
is foundCitizenscience
astronomers
comb through large data
sets to identify
pat- to
tion
into
the
gas
phase.
In
this
case,
the
grain
surfacetostarIRAS
16293-2422
couldbereproduced
using
a
terns
and
objects
that
are
not
easilyfound
throughautomated
processes.
The
Milky
be a (eg.
significant
improvement
over
DR1.
We
that
proton transfer
reactions
betweencommon
ice manmodellingwork
Coutens
et al. 2018).
However,theassess the reliability of IR bow shocks via
Way Project(MWP), a citizen
scienceinitiativeon theZooniverse
platform,
presents
acts
toimprovetheefficiency
offormation,bringing
remodelthatassumedneutralparentspecies
were
able
to
comparison
toexpertidentifications
andthecoloursofcandidatebow-shockdriving
tle major
speciesthat sublimate
in internet
hot incorescanefficiently
formationroutes of COMs
starwith
forming
regions
users
infrared(IR) images from Spitzer Space Telescope Galactic planestars in the 2MASS
point-source
catalogue.
We
hence
identify
highly-reliable
subsets
actants
togetherinto
onetarlocation and potentially lowerreact
inonthewarmtogas.
MWPvolunteerschemicalmake classification drawings
the images
identify
produce
COMs(Taquetet al.surveys.
2016).
Further,remains
an openquestion.
geted andclassesof astronomical
objects.
We presentthe
MWP second data
release(DR2)
of 1394 DR2 bubbles453
bow-shockdrivingstars.
Uncertainties
onobjectcoordiAlternatively,
COMs
in
the
gas phasemay
be best ex-coreing
theenergyrequired.
Modelsof botha prestellar
It is possibleform
in theparameters
gasreduction
phaseareof included
an updated
data
pipeline
written in
We aggregate
millionnatesthatand COMs
bubbleandsize/shape
inPython.
the DR2
catalog.⇠3Comparedclassifications made by MWP volunteers during
the years
2012–2017
toetproducetheplainedbygrain
surfaceformation
followedby desorp(L1544
Vasyuninal.
2017;Quénard
etal.
2018) andstar formingwith
regions.
modelshave shown
DR1, Forthe example,
DR2
moreandaccurateshapesand sizes.
DR2 bubbles
catalogue, catalogue
which containsprovides
2600 IR bubbles
599 candidatebow-shockdriving Thetion
gasphase.
In threethiscase, theetgrainsurface
Corresponding
JonathanHoldshipaassessed
hotintocorino(IRAS
16293
B Quénard
al. 2018)
havestars.
The reliability
bubbleidentifications,asby thecomparison
to visual
idenDR2 catalogue
identifies
311
newof bow
drivingstar
candidates,
includingthat protonauthor:transfer
reactions
betweencommonice shockmantifications
bytrainedexpertsNGC
and scoring
byand
a actsmachine-learningalgorithm,
is found tothe
jrh@star.ucl.ac.uk
toimprovetheefficiency
offormation,bringing
reassociated
with
the
giant
H
ii
regions
3603
RCW
49.
had
success
implementingdi↵usion-reaction
mechatle species that sublimate inbe ahotcoresimprovement
can efficiently
significant
over DR1. We assess the reliability of IR bow shocks via
actants
togetherbow-shock
into onelocation and potentially lowercomparison
expert identificationsof candidate
driving
produce COMs (Taquet et al.
2016). toFurther,chemical and the colours