Star Formation Newsletter#345 30-35
Yusuke Aso (KASI)

Quantifying Variability of YSOs in the Mid-IR Over Six Years with NEOWISE

iv:2107.10751v1 [astro-ph.SR] 22 Jul 2021

Wooseok Park,1 Jeong-Eun Lee,1 Carlos Contreras Peña,2, 3 Doug Johnstone,4, 5 Gregory Herczeg,6, 7
Sieun Lee,1 Seonjae Lee,8 Anupam Bhardwaj,9 and Gerald H. Moriarty-Schieven4
1 School of Space Research, Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 17104, Korea:jeongeun.lee@khu.ac.kr
2 Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB, UKØ 変光ß突発降着、⾮⼀様円盤、磁気リコネクション、連星、星の⾼温低温スポット。
3 School of Physics, Astrophysics Group, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
4 NRC Herzberg Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC, V9E 2E7, CanadaØ 全光度の変化を⾒るならMIR。
5 Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Elliot Building, Victoria, BC, V8P 5C2, Canada
6 Kavli Institute for Astronomy and Astrophysics, Peking University, Yiheyuan 5, Haidian Qu, 100871 Beijing, China
Ø Spitzer+WISEで若いほど原始星アウトバーストが多い。
7 Department of Astronomy, Peking University, Yiheyuan 5, Haidian Qu, 100871 Beijing, China

8 Department 0-IIIをカバー。
Ø NEOWISEはClassof Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea
9 Korea Astronomy and Space Science Institute (KASI), 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Korea
Ø 0.5-6.5年のMIR測光。1700/5400 (原始星0/Iの55%, 円盤IIの33%, PMS IIIの15%)で変光。

ABSTRACT

Variability
in young(YSOs)
be 22
causedby various
time-dependent phenomena
Ø WISE W1 3.4µm, W2
4.6 stellarµm, objects
W3 12µm,canW4µm,6"-12"、
associated with star formation, including accretion rates, geometric changes in the circumstellar disks,
半年毎に全天,14 hydromagnetic
epochs, 10-20
exposures/epoch~数⽇。
stochastic
interactions
between stellar surfaces and inner disk edges, reconnections
withinthestellarmagnetosphere,andhot/coldspots on stellar surfaces. We uncover and characterizeØ W2で5 epochs, 不確かさ<0.2 mag, 座標が既知のものを使⽤。
⇠1700 variables from a sample of ⇠5400 YSOs in nearby low-mass star-forming regions using mid-IR
light curves obtained from the 6.5-years NEOWISE All Sky Survey. The mid-IR variability traces awide range of dynamical, physical, and geometrical phenomenon. We classify six types of YSO mid-IR
Ø 光度曲線全体の偏差/観測誤差>3、ΔW2>3σで変光同定。
variability based on their light curves: secular variability (Linear, Curved, Periodic) and stochastic
Ø Lomb-Scargle
periodogram解析と線形フィット。
variability(Burst, Drop, Irregular ). YSOs in earlier evolutionary stages have higher fractions ofvariables and higher amplitudes for the variability, with the recurrence timescale of FUor-type outbursts
Ø 雑⾳による誤報率が線形フィットで低ければ線形。
(defined here as W1 or W2 > 1 mag followed by inspection of candidates) of ⇠1000 years in the early
embedded protostellar phase. Known eruptive young stars and subluminous objects show fractions ofvariables similar to the fraction (⇠ 55%) found in typical protostars, suggesting that these two distinct
types are not distinct in variability over the 6.5-year timescale. Along with brightness variability, we
also find a diverse range of secular color variations, which can be attributed to a competitive interplay
between the variable accretion luminosity of the central source and the variable extinction by material
associated with the accretion process.

iv:2107.10751v1 [astro-ph.SR] 22 Jul 2021

Quantifying Variability of YSOs in the Mid-IR Over Six Years with NEOWISE
Wooseok Park,1 Jeong-Eun Lee,1 Carlos Contreras Peña,2, 3 Doug Johnstone,4, 5 Gregory Herczeg,6, 7
Sieun Lee,1 Seonjae Lee,8 Anupam Bhardwaj,9 and Gerald H. Moriarty-Schieven4
1 School of Space Research, Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 17104, Korea:jeongeun.lee@khu.ac.kr
2 Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB, UK
3 School of Physics, Astrophysics Group, University of Exeter, Stocker Road, Exeter EX4 4QL, UK

4 NRC Herzberg
Secular(29%)
Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC, V9E有意な線形
2E7, CanadaØ Linear。負勾配が多いà減衰が⻑い。
6 Kavli Institute for Astronomy and Astrophysics, Peking University, Yiheyuan 5, Haidian Qu, 100871 Beijing, China
7 Department of Astronomy, Peking University, Yiheyuan 5, Haidian Qu, 100871 Beijing, China
Ø 周期3-13年Curved。
8of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, KoreaØDepartment
周期<3年Periodic。
9 Korea
Astronomy and Space Science Institute (KASI), 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Korea

5 Department of Physics and Astronomy, University of Victoria, 3800 Finnerty Road, Elliot Building, Victoria, BC, V8P 5C2, Canada

ABSTRACT
Variability in young stellar objects (YSOs) can be caused by various time-dependent phenomena
associated with star formation, including accretion rates, geometric changes in the circumstellar disks,stochastic hydromagnetic interactions between stellar surfaces and inner disk edges, reconnections
within the stellar magnetosphere, and hot/cold spots on stellar surfaces. We uncover and characterize⇠1700 variables from a sample of ⇠5400 YSOs in nearby low-mass star-forming regions using mid-IR
Stochastic
(71%)
light
curves obtained
from the 6.5-years NEOWISE All Sky Survey. The mid-IR variability traces a
wide
range
of
dynamical,
physical, and geometrical phenomenon. We classify six types of YSO mid-IRØ 数epochs（1-2年）のみの変光。
variability based on their light curves: secular variability (Linear, Curved, Periodic) and stochastic
Ø (med- min
orIrregularmax)>0.8(max- evolutionary stages have higher fractions ofvariability(Burst,Drop,). YSOs in earlier
variables
and Burst
higher amplitudes
for the variability, with the recurrence timescale of FUor-type outbursts
min)or Drop。
(defined here as W1 or W2 > 1 mag followed by inspection of candidates) of ⇠1000 years in the earlyØ その他Irregular。
embedded
protostellar phase. Known eruptive young stars and subluminous objects show fractions ofvariables similar to the fraction (⇠ 55%) found in typical protostars, suggesting that these two distinct
types are not distinct in variability over the 6.5-year timescale. Along with brightness variability, we
also find a diverse range of secular color variations, which can be attributed to a competitive interplay
between the variable accretion luminosity of the central source and the variable extinction by material
associated with the accretion process.

の続き

iv:2107.10751v1 [astro-ph.SR] 22 Jul 2021

Quantifying Variability of YSOs in the Mid-IR Over Six Years with NEOWISE
Wooseok Park,1 Jeong-Eun Lee,1 Carlos Contreras Peña,2, 3 Doug Johnstone,4, 5 Gregory Herczeg,6, 7
Sieun Lee,1 Seonjae Lee,8 Anupam Bhardwaj,9 and Gerald H. Moriarty-Schieven4

減光優勢
⾚化

の続き

1 School of Space Research, Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 17104, Korea:jeongeun.lee@khu.ac.kr
2 Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB, UK

School of Physics, Astrophysics Group, University of Exeter, Stocker Road, Exeter EX4 4QL, UKØ 4 NRC
Dropは不均⼀物質、Burstは粘性磁気不安定。Linearは降着
Herzberg Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC, V9E 2E7, Canada
5 Department of Physics
円盤上の降着率変化。Periodic,
Curvedは連星や内円盤
and Astronomy, University of Victoria, 3800 Finnerty
Road, Elliot Building, Victoria, BC, V8P 5C2, Canada （減光も増える）
6 Kavli Institute for Astronomy and Astrophysics, Peking University, Yiheyuan 5, Haidian Qu, 100871 Beijing, Chinaの⾼さ変化。
7 Department of Astronomy, Peking University, Yiheyuan 5, Haidian Qu, 100871 Beijing, China
8 Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea
Ø 変光率は0/I, II, IIIで55, 33, 15%、強度変化も0/Iが~3倍
9 Korea Astronomy and Space Science Institute (KASI), 776 Daedeokdae-ro, Yuseong-gu, Daejeon 34055, Korea
⾼いà進化。
戻る
ABSTRACTØ FUor/EXorの60%, VeLLO/LLSの55%à6.5年スケール
Variability
in young stellar objects (YSOs) can be caused by various time-dependent phenomena
点の⾊は時刻で同じ。
associated with star formation, including accretion rates, geometric changes in the circumstellar disks,
しかしFUor/EXorはほぼSecular、VeLLO/LLSは半分がstochastic
hydromagnetic interactions between stellar surfaces and inner disk edges, reconnections
within Irregularà変光では分けられない。
the stellar magnetosphere, and hot/cold spots on stellar surfaces. We uncover and characterize
内壁が降着
3⇠1700 variables from a sample of ⇠5400 YSOs in nearby low-mass star-forming regions using mid-IR
light curves obtained from the 6.5-years NEOWISE All Sky Survey. The mid-IR variability traces awide range of dynamical, physical, and geometrical phenomenon. We classify six types of YSO mid-IR
Ø FUor（ΔW1, W2>3 mag, linear）から間隔を推定。
variability based on their light curves: secular variability (Linear, Curved, Periodic) and stochastic
N: 観測原始星数=735-1059
variability(Burst, Drop, Irregular ). YSOs in earlier evolutionary stages have higher fractions ofvariables
and higher amplitudes
t: 観測時間=6.5
yr for the variability, with the recurrence timescale of FUor-type outbursts(defined here as W1 or W2 > 1 mag followed by inspection of candidates) of ⇠1000 years in the earlyk: 観測FUor数=2-9embedded
protostellar phase. Known eruptive young stars and subluminous objects show fractions ofvariables
similar to the fraction (⇠ 55%) found in typical protostars, suggesting that these two distinct
τ: バースト間隔
types are not distinct in variability over the 6.5-year timescale. Along with brightness variability, weτ=Nt/(k+1)=500-2300
yr
also
find a diverse range of secular color variations,which can be attributed to a competitive interplay
between the variable accretion luminosity of the central source and the variable extinction by material
associated with the accretion process.

戻る

内壁が⾼くなり⾚化

Susanne Pfalzner1, 2 and Amith Govind1, 2
1 Jülich Supercomputing Center, Forschungszentrum Jülich, 52428 Jülich, Germany
2 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany

8.10296v1 [astro-ph.SR] 23 Aug 2021

4

Close stellar flybys common in low-mass clusters(Received August 24, 2021)

Submitted to ApJ

Ø ⼩質量星形成領域の円盤で渦状腕やtruncationがよく⾒つかるが、flybyは稀と思われていた。
Ø それを確かめるためにクラスターをシミュレーション。
ABSTRACT4‒3
Ø 環境的影響は>10/pcで顕著。半質量半径を1.3pcに固定すると>1000個の⼤質量クラスターで
Numerous
protoplanetary
discs show distinct spiralarms features. While possibly caused by arange of processes, detailed pattern∝Ranalysis1.6-2.1
pointsat close stellar flybys as cause for some of them.
のみ可能。しかし太陽系近傍ではMなので、⼩質量ほど⾼密度になる。
chmSurprisingly, these discs reside in young low-mass clusters, where close stellar flybys are expected to
be rare. This fact motivated us to take a fresh look at the frequency of close flybys in low-mass
Pfalzner & Govind
clusters. In the solar neighbourhood, low-mass clusters have smaller half-mass radii than their more
massive counterparts. We show that this observational fact results in the mean and central stellar
density of low-mass clusters being approximately the same as in high-mass clusters, which is rarelyreflected in theoretical studies. We perform N-body simulations of the stellar dynamics in young
clusters obeying the observed mass-radius relation. Taking the mean disc truncation radius as a proxy
for the degree of influence of the environment, we find that the influence of the environment on discs
is more or less the same in low- and high-mass clusters. Even the fraction of small discs (< 10 au) is
グレーより上は⻘がnearly identical. Our main conclusion is that the frequency of close flybys seems to have been severely
underestimated for low-mass clusters. A testable prediction of this hypothesis is that low-mass clusters
⾚より多い。
should contain 10%–15% of discs smaller than 30 au truncated by flybys. These truncated discs should
King W=9プロファ
be distinguishable from primordially small discs by their steep outer edge.

イル。

Keywords: protoplanetary disks — local interstellar matter

クラスター質量と半径の相関1. INTRODUCTION

The observed diversity in the structure of protoplanetary discs (for example, Andrews 2020; van der Marel et al.

8.10296v1 [astro-ph.SR] 23 Aug 2021

the complexity and numerical challenges the formation of massive clusters still faces. Thus the simulation sets only inwhen all stars are formed, and we take the mass-radius relations discussed in section 2 at face value. Naturally, any
Closestellarflybyscommonlow-massclusters
7 and gradually grows tohigh-massclustermust go througha phase where
it starts initially with a small number of stars
Close stellar
flybyscommonininlow-massclusters
its final size. However, such cluster formation simulations are still limited to clusters containing ⌧ 1000 stars, at the
1, ratio2
1, 2we revert
forthethe mass
resolution
required
here.Govind
Therefore,
to the close
often usedof following
each star is recorded, meaning forSusanneeach least
star,
and
periastron
distanceof eachflybymethod
is listed.
In the stellar dynamics
Pfalzner
and
Amith
in
the
fully
formedclusters
instead.
The
limitationsof
thisapproacharediscussedin
sectionthe second step, the truncation disc size for each of the close flyby events is calculated. Afterwards, we use the mean 5.
1 Jülich Supercomputing Center,
We performof the dynamics
of clusters
N stars using the simulation code Nbody6++. In the
ForschungszentrumJülich, 52428
Germany
value of the final truncation
disc size to measurethesimulations
cluster environment’se↵ect Jülich,on containing
formingplanetarysystems.
2 Max-Planck-Institut fürsimulations,
a
star
is
represented
by
a
test
particle
with
a
given
mass, position and velocity. The particles’ positions
Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
are chosen so that the resulting stellar number density distribution obeys a King profiles (King 1966). The reason isDiscthat King 3.2.
profilesseemtruncation
to present young clusters well (Hillenbrand & Hartmann 1998; Harfst et al. 2010; Nürnberger(Received
August24, 2021)&
Petr-Gotzens
2002);
however,there
no generalThis
observational
whether
W=7, W=8 or W=9 is the best
We start with the artificial situation of all disc having a size of 1000
auisinitially.
value isagreement
typical forthe top-end
choice. Here we mostly use a King profile with W0 > 9, but also discuss in section 5 the role of the chosen profile forof the size of observed discs. (Andrews et al. 2018b).
The reason
Submitted
to ApJis that we only intend to obtain a measure of the
our results.
influence of the environment rather than aTherealistic
representationof thedisc masses
sizes infollowing
a specificThus
we obtain
individual
test particles are
assignedthe cluster.
initial massfunction(IMF) by Kroupa (2001)
the size that a standard disc is truncated to due to thecloseflybysofaparticularclusterenvironment.
Thistruncation
8
ABSTRACT
0.3>
0.01  m/M < 0.08
disc size is obtained the following way:<m
1.3
Numerous
protoplanetary
discs
show
distinctspiralarms
features.
While
by a
⇠(m)
/
(2)
m
0.08possibly
them/M<caused0.5of a parameterIn this work, all encounters were assumed to be parabolic, prograde and coplanar,using
results
>
:
2.3
range
of processes,
detailed
patternbyanalysis
pointsat closestellarflybys
as 0.5cause
forof them.
m truncation
 m/M
study
of star-discencounters
performed
Breslau etal. (2014).
In thiscase,
thedisc, somesize rdisc
after theØ シミュレーションは全星ができた状態で始め、2 Myr後にガスが無くなってクラスターが膨張。Nbody6++。
Ø King W=9に従って星を配置。星質量はあるIMFを使⽤。0.08-150 Msun。primordial singleのみ。
Ø ビリアル平衡を仮定してマクスウェル速度分布。
Ø モデルP: γ=1.7, K: γ=2.0, V: Rc=1.3 pc。
Surprisingly,
these discs
young low-mass clusters, where close stellar flybys are expected to
flyby
can be approximatedas reside in withthe lower mass limit set to 0.08M (hydrogen burning limit) and an upper mass limit of 150M , which is theØ flyby発⽣時の質量⽐と近星点距離を記録。シミュレーション後にトランケーションを評価。
be rare. This fact motivated us acceptedtoa freshlook(Figerat theof closeflybys in low-mass( takeuppermass limit
2005;frequency
Weidner & Kroupa2006).
0.32
Ø 初めは円盤半径は全て1000
au。
0.28· rall· clusters
M21
ifsingle
rdiscsmaller< rprevious
Initially,clusterstars ,arestars,
meaning
primordial
binaries
excluded.
This approximation is chosenclusters. In the solar neighbourhood,
low-masshave
half-mass
radii
thanastheir
more
peri
rdisc =for simplicity(3) inclusion of primordialintheconsecutive
processing
of
the
e↵ect
of
flybys
on
disc
size,
where
the
M1:
host
,
iffactrdiscresults
rprevious
massive counterparts. We show thatrprevious
this observationalin the M21=M2/M1,
mean and central stellar
binaries would significantly increase the complexity. The absence of primordial binaries might lead to underestimating
density of low-mass clusters beingejections
approximately
theduesame
as inhigh-massclusters,
is 1975).
rarelyfrom the cluster
to strong
few-bodyinteractions(Heggie which
1975; Hills
For a more detailed discussion
Ø V以外は⼤⼩質量で同じ。
where rperi is the periastron distance between
the
two
stars
involved
in
a
close
flyby
in
au.
M
=
M
/M
is
the mass
21
2
1
of omitting
binariesin this typeof study, see of
Olczakal. (2006).dynamics
Besides, binaries
can accelerate a cluster’s expansion
reflected in theoretical studies. We
perform
N-bodysimulations
theet stellar
in young
ratio ofPは13%が1000
the two stars, with M1 auのまま。
being theprocess
massandof thedisc-hostingstar
M(Kroupa
theKaczmarek
perturberetstar.
ris
2 that of
reducetheTakingencounterrateandfaster2001;
Ø ⼩質量Vは95%,
clusters obeying the observed
mass-radiusrelation.
themeandisc truncation
radiusal.as2011).
a previous
proxy
the disc size before the encounter.
Potentially existing initial mass segregation in the clusters was neglected. The occurrence of mass segregation withinfor thedegreeof influence
we debate,
find
that
the
thetheenvironment
discs
Ø Pは10-30%が30
au以下に。
clusters
underwhether
it influenceisthe
primordial—foundindiscthe dense
core onphaseof theInclinedor retrograde
flybys ofarethelessenvironment,
efficientis still
to removematerial
fromdisc, ofandtruncation
radii
arecluster formation process
is
more
or
less
the
same
in
lowandhigh-massclusters.
Eventhefraction
of
small
discs
(<
10
au)
is
therefore larger (Clarke & Pringle 1993; Bhandare et al. 2016). However, the di↵erence to coplanar flybys is notØ 配置をPlummer（〜⼩W）にしても同じ。
nearly identical.
Our mainconclusion
is thatthe frequency
flybys radii
seemshaveto haveseverely
extremely
large. Applying
the result
for coplanar
flybysmeans that oftheclosetruncation
to be been
regardedas lowerØ スパイラルが⾒つかったTaurusで<30
auはunderestimatedfor low-mass
A testablepredictionof thisis thatlow-massclusters
limits.
Similar, hyperbolic
flybys clusters.
are less e↵ectivein disctruncation
thanhypothesis
parabolic ones.
However,more
eccentric
クラスター中⼼にいて、割合も合う。
should contain
10%–15%more
of discs
smallerthan 30mass
au truncatedby flybys.
Thesefocusestruncateddiscs should
encounters
are significantly
commonin higher
clusters. Since
our study
on low-massclusters,
approximating
the flybyfrom
pathprimordiallyas parabolic issmall
likely discs
justified.
Moreover,applyedge.
these simplifications in all simulations
be distinguishable
by theirsteepweouterØ 端が鋭利なら光蒸発とも区別可能。
identically, so the relative di↵erences between the diverse cluster environments should not be a↵ected. Here, only aØ 今まで知られていないのは⼩質量の10%だ
summaryof themethod has been
provided;
weinterstellar
refer the reader
to Breslau et al. (2014) for more information on the
Keywords:
protoplanetarydisks— localmatterdisc
size
determination
duringclose
stellarencounters.
と統計的に不⾜、0.1 Myrで中⼼から離れる
100 au以下になるエンカウント
ため。
3.3. 1.Observational
uncertainties
INTRODUCTION
Close stellar flybys common in low-mass clusters

13

Figure 7. Location of the members of the Taurus star forming region according to Luhman (2018). The systems showing
spiral arms attributed to stellar flybys (Cuello et al. 2019; Ménard et al. 2020) are indicated as blue circles. Note, that someare located close to each other, so that they are better identified by their labels. The red symbols indicate the location of thestars for which Andrews et al. (2018a) determined disc sizes. Discs with sizes smaller than 30 au are indicated as red crosses,
whereas discs with sizes exceeding 30 au are shown as circles. The disc sizes for RW Aur A & B were taken from Rodriguez
et al. (2018b)

As mentioned
in section
the exponent
in the derived discs
mass-radiusrelations Andrews
for young2020;
stellarvan
clustersin theet al.
The observed
diversityin the1,structureof protoplanetary(for example,
der Marelsolar neighbourhood varies between.
= 1.7 — 2.0 and that of theconstant spans the range of C= 359 — 1263.

LETTER TO THE EDITOR

An unbiased NOEMA 2.6 to 4 mm survey of the GG Tau ring: First
detection of CCS in a protoplanetary disk
N. T. Phuong1,2 , A. Dutrey3 , E. Chapillon3,4 , S. Guilloteau3 , J. Bary5 , T. L. Beck6 , A. Coutens7 ,O. Denis-Alpizar8 , E. Di Folco3 , P. N. Diep2 , L. Majumdar9 , J.-P. Melisse3,4 , C.-W. Lee1,10 , V. Pietu4 ,T. Stoecklin11 , and Y.-W. Tang121

Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon, Korea
e-mail: tpnguyen@kasi.re.kr
2
Department of Astrophysics, Vietnam National Space Center, Vietnam Academy of Science and Techonology, 18 Hoang Quoc
Viet, Cau Giay, Hanoi, Vietnam
N. T. Phuong et al.: An unbiased NOEMA 2.6 to 4 mm survey of the GG Tau ring
3
Laboratoire d’Astrophysique de Bordeaux, Université de Bordeaux, CNRS, B18N, Allée Geo↵roy, Saint-Hilaire 33615,
Pessac, France
4
IRAM, 300 Rue de la piscine, 38406 Saint Martin d’Hères Cedex, France
5
Department of Physics and Astronomy, Colgate University, 13 Oak Drive, Hamilton, New York 13346, USA
6Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, Maryland 21218, USA
7
Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, UPS-OMP, CNRS, CNES,
9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
8
Instituto de Ciencias Químicas Aplicadas, Facultad de Ingeniería, Universidad Autónoma de Chile, Av. Pedro de Valdivia 425,
7500912 Providencia, Santiago, Chile
9
School of Earth and Planetary Sciences, National Institute of Science Education and Research, HBNI, Jatni 752050, Odisha, India
10
University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea
11
Institut des Sciences Moléculaires, UMR5255-CNRS, 351 Cours de la libration, 33405 Talence, France
12
Academia Sinica Institute of Astronomy and Astrophysics, PO Box 23-141, Taipei 106, Taiwan

Ø PPDの化学は分⼦雲からとその場。GG Tau Aa-Ab1/b2の円盤は⼤きく、低温で重いので分⼦化学向き。
Ø NOEMA, 2.6-4.2 mm, dv=0.2-0.3 km/s
Ø この８つは超微細構造の⽐とピークから光学的に薄い。
Ø 南東ホットスポットによる⾮対称
Received 27 July 2021 / Accepted 27 August 2021

⽩は連続波リング
ABSTRACTA&A 653, L5 (2021)

Context. Molecular line surveys are among the main tools to probe the structure and physical conditions in protoplanetary disks(PPDs), the birthplace of planets. The large radial and vertical temperature as well as density gradients in these PPDs lead to acomplex chemical composition, making chemistry an important step to understand the variety of planetary systems.
Aims. We aimed to study the chemical content of Fig.
the protoplanetarysurrounding
GG TauA, a well-known
tripleTauri+ (1system.
2. From left todisk
right,
top to bottom:
integrated
intensity map
ofTHCO0), CS(2 1), CN(1 0), HCN(1 0), HNC(1 0), N2 H+ , CCH, and+H13 CO(1 to0).observe
The white
ellipseslines
mark
inner
anddozenouter molecules.
edges of the dust ring at 180 au and 260 au, respectively. The beam size
Methods. We used NOEMA with the new correlator
PolyFix
rotationalat the⇠2.6approximate
to 4 mm froma few
13
is indicatedin molecular
the lower left
cornerand
and thethe abundancecolour scalerelativeis on theunits of
We analysed the data with a radiative transfer code
to derive
densities
to right
CO,iswhich
weJy beam 1 km s 1 . The intensity was integrated in the velocity
compare to those of the TMC1 cloud and LkCa 15range
disk.from 4.0 to 9.0 km s 1 with the threshold of 3 . Contour levels are spaced by 5 in the maps of HCO+ and CS(2 1), and 3 in the maps ofCN, HCN,
HNC,
N2 H+ , CCH,andH13 CO(1 160). other molecules in the GG Tauri
Results. We report the first detection of CCS in PPDs.
We alsomarginallydetectOCS
and+findouter disk. Ten of them had been found previously, while seven others (13 CN, N2 H+ , HNC, DNC, HC3 N, CCS, and C34 S) are newdetections in this disk.
+
Conclusions. The analysis confirms that sulphur chemistry is not yet properly understood. The D/H ratio, derived from DCOTable/HCO2.+ ,GG Tau parameters.
DCN/HCN, and DNC/HNC ratios, points towards a low temperature chemistry. The detection of the rare species CCS confirms that
GG Tau is a good laboratory to study the protoplanetary disk chemistry, thanks to its large disk size and mass.
GeometryLaw

dprj半径対速度

R<200 auの分離はtidal cavity

Key words. astrochemistry – molecular data – protoplanetary disks – stars: individual: GG Tau A

1. Introduction

Inclination
Orientation
Systemic velocity

35
7
6.4 km s 1

V(r) = 3.4 ( 100r au ) 0.5
T (r) = T 0 ( 200r au ) 1.0⌃(r) = ⌃250 ( 250r au ) 1.5(km s 1 )(K)
(cm 2 )

layer just below it, while molecules are frozenNotes.
on thedust
The inner and outer radii are 180 and 600 au for detectedLETTER TO THE EDITOR

An
unbiased NOEMA 2.6 to 4 mm survey of the GG Tau ring: First
Fig. 2. From left to right, top to bottom: integrated intensity map of HCO+ (1 0), CS(2 1), CN(1 0), HCN(1 0), HNC(1 0), N2 H+ , CCH, anddetection
CCS
in a protoplanetary
H13 CO+ (1 0). The
white ellipses ofmarkthe approximate
inner and outer edgesdiskof the dust ring at 180 au and 260 au, respectively. The beam size
is indicated in the1,2lower left cornerand the colour
scale is on3 the right 5is units of Jy
beam 1 km7 s 1 . The intensity
was integrated in the velocity
の続き
3
3,4
6
1
T. Phuong
A. sDutrey, E.
Chapillon, S.3 Guilloteau, J. Bary,spacedT. L. Beck
, A.inCoutens,of HCO+ and CS(2 1), and 3 in the maps ofrangeN.from
4.0 to89.0 ,kmwiththethresholdof.
Contourlevels
are
by
5
the
maps
3 , P. N.
2
93,41,10 , V. Pietu4 ,O. Denis-Alpizar
E.+ ,Di
FolcoandCN,
HCN, HNC, N2, H
CCH,
H13 Diep
CO+ (1, L.
0).Majumdar , J.-P.12Melisse , C.-W. Lee
11
T. Stoecklin, and Y.-W. Tang

1

Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon, Korea
Table 2. GG Tau parameters.
e-mail: tpnguyen@kasi.re.kr
2
Department of Astrophysics, Vietnam National Space Center, Vietnam Academy of Science and Techonology, 18 Hoang Quoc
Cau Giay, Hanoi, Vietnam
150 3 Viet,0
Geometry
Law
Laboratoire d’Astrophysique de Bordeaux, Université de Bordeaux, CNRS, B18N, Allée Geo↵roy, Saint-Hilaire 33615,
Pessac, France0
Inclination
35
V(r) = 3.4 ( 100r au ) 0.5(km s 1 )4
IRAM, 300 Rue de la piscine, 38406 Saint Martin d’Hères Cedex, Francer5
7
T (r) = T 0 ( 200 au ) 1.0(K)
Department of Physics and Astronomy, Colgate University, 13 Oak Drive, Hamilton, New York 13346,Orientation
USA
6
150 Institute, 3700 San Martin Drive, Baltimore, Maryland 21218, USAr
1
1.5
Space Telescope Science
Systemic velocity
6.4 km s⌃(r) = ⌃250 ( 250 au )(cm 2 )
7
34
13
13
Institut de Recherche en Astrophysique‒2 et Planétologie, Université de Toulouse, UPS-OMP, CNRS, CNES,
150
9 Av.
du Colonel Roche, 31028 Toulouse Cedex 4, France
8
Notes.
The
inner
and outerradii are 180 and 600 au for detected
Instituto de Ciencias Químicas Aplicadas, Facultad de Ingeniería, Universidad Autónoma deChile, Av.
Pedrode Valdivia
425,
7500912 Providencia, Santiago, Chile
molecules,
respectively,
and800
au for undetected molecules.
9
School of Earth and Planetary Sciences, National Institute of Science Education and Research, HBNI, Jatni 752050, Odisha, India
Yuseong-gu, Daejeon 34113, Republic of Korea
3 1011 University of Science and Technology, 217 Gajeong-ro,
2
Fig. 3.
Same
Fig. Moléculaires,
2, but for HUMR5255-CNRS,
N, respectively.
The33405
con-Talence, FranceInstitutdes asSciences
Cours de la libration,
2 CO and HC3351
12
13
5
Academia
SinicaInstituteofAstronomy
andAstrophysics,
POBox
23-141,
Taipei106, Taiwan
have chosen to only present their integrated
spectra(top) andthetour levels are spaced by 2 .
13Ø DiskFitでΣ をフィット。S系以外CO温度（T =25 K）、Fig. 4. Integrated spectra (with GausCSは⾚道⾯近くなのでS系はダスト温度（T =15 K）。こ
sian fits in red and fit results are indiの仮定は軽い分⼦でもΣ を2倍変える程度の影響。
cated) and radial-velocity diagram of CS,
C S(2 1), CCS, CS(2 1), CN, andØ CCSを初検出。Σ =1.5e12 cm 。３層気体粒⼦化学モデ
DNC obtained after making a Keplerian
ルNautilusの予想より20倍⾼い。
velocity correction.
Ø SO, SO2, HC Nはモデルと合うが、H Sはモデルの1%。
Ø 3.HMolecularTable
surface density at 250 au derived with DiskFit.
Table 4. Molecular abundance with respect to CO: 10 ⇥(Xmol /X CO ).
2Sがダスト粒⼦上で複雑な分⼦になるなど、S化学モデル
RV diagram (bottom) obtained after Keplerian velocity correcReceived 27 July 2021 / Accepted 27 August 2021に不完全な点があることを⽰唆。
tion, which best illustrate the detectability.
Molecules

The CN, HCN, HNC, HCO+ , CS, N H+ , and CCH lines were

2
Mol.
TMC-1
LkCa 15
Tau Mol.
TMC-1 LkCa 15
Tau
Surface density
Molecules
Surface density
ABSTRACTRegardingthe GG
undetected
molecules
list, we GG
mayhave
detected
at
high
S/N,
as
it
can
be
seen
in
Fig.
2.
All
lines
appear
2
2
+
18
4
(1)
4
(7)
4
34
(cm )Context. Molecular line surveys are among(cm)
C Oand physical
1.1 ⇥marginal10
2.8indetections⇥protoplanetary10
2.2(⇠2⇥
10 3 C) ofS OCS,. . . and .perhaps
..
10
±1
DCO
and
the main tools to probe the structure
conditions
disks

optically thin, as illustrated by thehyperfine ratios of HCN,
CN, 2250 (1)17 (3)
Ø13 dark cloud TMC1、遷移円盤LkCa
660 ±30
CS 13 C1500
230 ± HC
10 15 N,
the birthplace
radial and13
vertical temperature CN
as well as density
gradients
in3100these(8)PPDs
leadtoa detect
DCN.
However,could
not
O, N2520
D+(8), H13 CN,+ of planets. The large15と⽐較。
16(PPDs),(⇤) and
N
H
(see
Fig.
E.1),
and
also
by
the
peak
brightness
COD
1.10 ⇥ 10CCH,
CS
D
(2.6
±
0.03)
⇥
10
13 CN
13 CS + 11 (4)(10)
2 composition, making chemistry an important step to understandcomplex chemical
the variety of. planetary
13 systems.
15
+10
.
.
.
.
.
25
±
2.8
2.2
±
0.6
C, H triple
NC,
HOC, HCNH , HCCCHO, SO, SO2 , H2 CS,
15Aims.
(⇤) We+aimed
13 toK).
11
ØC18ラジカル（CN,CCH）がLkCa
15より少ないの
contentof theprotoplanetary
disk surrounding GG Tau A,HN
a well-known
system.
HCO
(5.5
O
D
2.42 ⇥ 10of
CSstudy theDchemical(2.6± 0.7)⇥ 10(2)(8)T Tauri600
(3)
CCH
5960
1200
±
30
CCS
240CH
...
13 ± 2
Methods.
We used NOEMA with the new correlator PolyFix
to observe rotational lines at ⇠2.6 to
4 mmCCD,
from a few
dozen molecules.
SiO,
HDO,
D
CO,
c-C
H
,
or
13 17
13
12
2
3
2
3 CN molecules.
CはGG
OUTauのリングがUVを遮断するから。
<1.2 ⇥ 10WeSome
CCS(1.5transfer± with0.2)code⇥a10tosufficiently
+
(1)
(9)
(1)
high
angularanalysedmoleculesthedata withDaobserved
radiative
derive moleculardensities
andtheabundance
relative
to
CO,
which
we
N2 H
7680
19.1
10.5 ± 0.5 OCS
1500...
0.4 ± 0.2
+disk.
10of the+ TMC1
and ±
LkCa
15⇥
CN
D (7.7 ± 0.1)resolution⇥compare1013 to thoseOCS
M cloud(4.5(HCO, HCN,
andN2.3))10display
a clear east-west
(2)
(8)
(6)
(9)
2H
HCN
1500
300 in the GG
57Tauri
±3
DCN
22
7.5
1.6 ± 1.0
Results.
We report the first detection of CCS13in PPDs. We12
also marginally detect
OCS and find
16 other moleculesØ13 CN
CCSがTMC1より少ないのはCCSがCSになる
(2)
(6)
(9)
D (2.8 ± 1.1)asymmetry.
⇥outer1012disk. p/o-H
10 /5.3⇥ 10the
Inthema tilted
Keplerian
disk,
2 CS
.
.
.
29
±
2
DNC
124
3.5
2.3 ± 1.1
Ten of
hadUbeen<8.2
found⇥previously,
while
sevenmaximum
others ( CN,HNC
Nopacity
H , HNC, 1500
DNC,
HC
N,
CCS,
and
C
S)
are
new
3. Radiative transfer modelling with DiskFit
13
12+
detections
in
this
disk.
CCH
D
(6.8
±
0.1)
⇥
10
SO
U
<4.5
⇥
10
was
obtained
along
the
major
axis,
resultingintwosymmetric
+
(2)
(8)
+
(5)
(11)
⼀⽅で、円盤でS
からCCSを作る経路の効率
HCO
596
350
125 ± 5 DCO
30
4.5
3.5 ± 0.2 (13)The analysis confirms that sulphur chemistry
is not yet properly understood.
ratio, derived from
DCO /HCO ,12
12+ + The D/H(1)
13
(12)
N2 H+
D (1.2 ± 0.1)peaks.
⇥Conclusions.
10
SO
U
<5.0
⇥
10
The
observed
asymmetryismostobviousin
HCO,
sugThedata
werecomparedintheuv-planewithvisibilities
pre2
H The
COdetection8.3
5.0 CCS confirms
3.4 ±that
0.2
DCN/HCN, and DNC/HNC
ratios, points towards a low temperature chemistry.
of the rare species+
1111
が悪いから。
N2 D
U<1.3 ⇥ gesting
10GG Tau isthat
SiO
Uto study<4.5⇥ 10 spot’a goodprotoplanetary
disk detectedchemistry, thanks
to CO
its 120
large disk
size
and mass.
itlaboratory
is related
tothethe‘hotat HPA
dictedfor13.6
a disktransfercode
DiskFit(2)(9) model(⇤) HCthe(12)1500
33 ± 2 using
N radiative
473 (2)7.3
4.6 ± 0.9
13

13

2

+

3

34

+

HCN
H13 CN
HC15 N
HNC

2

+

3

12
11
D (6.70 ± 0.04)⇥ 10words.
DCN
(1.9
±
1.2)
⇥ 10Phuong(Dutrey
et al.
2014a;MTanget al.
2016;
et–al.
2020).
Furet al. 2007). A description of DiskFit usage for GG Tau
Keyastrochemistry– moleculardata– protoplanetarydisks
stars:
individual:
GG Tau(Piétu
AU<1.6 ⇥ thermore,
1011
CCDmay U<1.0 ⇥ 1014there, while the HNC map(⇤)
CCHalso be enhanced
canbein the appendix of Phuong et al. (2020).
Notes. For para-Hfound
2 CO only in GG Tau. Since estimating the uncer11
10U<2.9 ⇥ suggests
10
HDO
U deficit <1.9
⇥ 10
a (marginal)
at thisposition.
Thethese
geometric
parameters(inclination, orientation) and theallmoleculesofstudies
1. Introduction
layer tainties
just belowfrom
it, while
aredi↵erent
frozen on the
dust was very difficult, we do not
D (3.4 ± 0.03)⇥ 1012DNC
D(2.7 ± 0.7) ⇥ 1011

arXiv:2108.12401v1 [astro-ph.SR] 27 Aug 2021

arXiv:2108.12401v1 [astro-ph.SR

explicar las curvas de luz usando extinción de la radiación estelar y emisión del polvo
dentro del agujero de un disco transicional. Para el objeto Mon-296, fuimos exitosos.
Sin embargo,para Mon-314 y Mon-433
nuestraevidencia
sugiereque contienen un
INTERPRETATION
OF OPTICALAND
IR LIGHT
CURVES
disco pre-transicional.
Para Mon-1308
un nuevo
ajuste delIN
espectro
usando el código
FOR TRANSITIONALDISKSCANDIDATESNGC 2264
USING THE
EXTINCTEDSTELLAR
RADIATIONAND
3D de transferencia
radiativa
Hyperion,nos permite
concluir que
esteTHEobjeto tiene un
EMISSION
OFdeOPTICALLY
THIN DUSTEsto
INSIDE
THEconHOLE
disco completoen lugar
un disco transicional.
coincide
trabajo previo
E. Nagel,1 F. Gutiérrez-Canales,1 S. Morales-Gutiérrez,1 and A.P. Sousa2
sobre Mon-1308 y también conque no podemos encontrar un ajuste de las curvas deDraft version: August 30, 2021
luz solo usando la contribución del polvo dentro del agujero de un disco transicional.
RESUMEN
En la región de formación estelar ABSTRACT
NGC 2264 hay objetos catalogados como anfitriones de discos transicionales de acuerdo al modelaje de su espectro. Cuatro miemIn the stellar
forming
regionthere
arey enobjects
catalogued
as hosting abros deeste conjunto
tienenNGC
curvas 2264
de luz enel óptico
el infrarrojo
provenientes
los telescopios
CoRoT
y Spitzer. modeling.
En este trabajo,
tratamosde simultáneamentetransitionalde disk
accordingto spectra
Fourmembersof this set have opexplicar
lascurvasdeluz
usandoextincióndelaradiaciónestelaryemisióndel polvo
tical and infrared light curves coming from the CoRoT and Spitzer
telescopes. In
dentro del agujero de un disco transicional. Para el objeto Mon-296, fuimos exitosos.
this work,Sinweembargo,
try to para
simultaneously
explaintheevidencia
light curves
using
the extinctionofMon-314 y Mon-433
nuestrasugiere que
contienenunpre-transicional.
Para Mon-1308
un dustnuevo ajuste
deltheespectrocódigothe stellar disco
radiationand emissionof theinsideholeusandoof aeltransitional
disk.
3D
de
transferencia
radiativa
Hyperion,nospermiteconcluirqueeste
objetotieneun
For the object Mon-296, we were successful to do this. However, for Mon-314, anddisco completo en lugar de un disco transicional. Esto coincide con trabajo previo
Mon-433 ourthathost aencontrar
pre-transitional
disk.
For
sobreevidence
Mon-1308 ysuggests
también conquetheyno podemos
un ajuste de lascurvasde Mon-1308
a new spectra
fitting
the 3Ddelradiative
transfer
code
Hyperion,allow us to conluz solo
usandousing
la contribuciónpolvo dentrodel agujero
de undisco transicional.

clude that this object host a full-diskABSTRACT
instead of a transitional disk. This is in accord
to previousInwork
on Mon-1308
wecatalogued
cannot asfind
a fitaof the lightthe stellar
forming regionand
NGCwith2264thetherefact
are that
objects
hostingtransitional
disk
accordingtospectramodeling.
Fourmembers
of
this
set
have
opcurves only using the contribution of the dust inside the hole of a transitional
disk.

tical and infrared light curves coming from the CoRoT and Spitzer telescopes. In
this work, we try to simultaneously explain the light curves using the extinction of
Key Words:
dust, extinction — protoplanetary disks — Stars: pre-main sequence
the stellar radiation and emission of the dust inside the hole of a transitional disk.
For the object Mon-296, we were successful to do this. However, for Mon-314, andMon-433 our evidence suggeststhat they host a pre-transitional disk. For Mon-1308
1. INTRODUCTIONa new spectra fitting using the 3D radiative transfer code Hyperion, allow us to conclude that this object host a full-disk instead of a transitional disk. This is in accord
Spectraland photometric variability of young stellar objects (YSOs) is the usual
to previous work on Mon-1308 and with the fact that we cannot find a fit of the lightoutcome ofcurves
multiwavelength
campaigns
2015, 2016;
only using the contributionof the(Stauffer
dust inside etthe al.
hole2014,
of a transitional
disk. Cody et al.

分光モデルから遷移円盤と思われる4個の⽳の光度曲線とダスト放射を説明。
Mon-296はOK。Mon-314とMon-433はpre遷移円盤ではない。Mon-1308は完全な円盤。
2014; Morales-Calderón
et al. 2011). For young stars in NGC 2264, Stauffer et al.
Key Words: dust, extinction — protoplanetary disks — Stars: pre-main sequence(2014) extract the accretion burst dominated light curves (lcs), Stauffer et al. (2015)
1. INTRODUCTION
1 Departamento de Astronomı́a, Universidad
de Guanajuato, México.
2 Institut de Planétologie et d’Astrophysique de Grenoble, Université Grenoble Alpes, France.

Spectral and photometric variability of young stellar objects (YSOs) is the usual

The first spectroscopically confirmed brown dwarfs in NGC 2264
MNRAS 507, 4074–4085 (2021)

Advance Access publication 2021 August 23

https://doi.org/10.1093/mnras/stab2394

Samuel Pearson,1‹ Aleks Scholz,1 Paula S. Teixeira ,1 Koraljka Mužić2 and Vı́ctor Almendros-Abad2
1 SUPA, School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK
first spectroscopically confirmed brown dwarfs in NGC 2264
2The
CENTRA, Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, P-1749-016 Lisboa, Portugal
Samuel Pearson,1‹ Aleks Scholz,1 Paula S. Teixeira ,1 Koraljka Mužić2 and Vı́ctor Almendros-Abad2
1 SUPA, School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, UK

2 CENTRA, Faculdade
Accepted
2021 August
16. Universidade
Received 2021
August16;
in originalform 2021
JulyPortugal
1de Ciências,de Lisboa,
Ed. C8,CampoGrande, P-1749-016
Lisboa,Key words: catalogues – surveys – brown dwarfs – stars: low-mass.

Downloaded from https://academic.oup.com/mnras/article/507/3/4074/6356573 by KASI user on 05 O

We
present spectroscopic follow-up observations of 68 red, faint candidates from our multi-epoch, multiwavelength, previously
ABSTRACTpublished
survey of follow-up
NGC 2264.
Usingofnear-infrared
spectraVLT/KMOS,
we measure
spectral types and extinction for 32
We present spectroscopic
observations
68 red, faint candidates
fromfrom
our multi-epoch,multiwavelength,previously
published
survey
of
NGC
2264.
Using
near-infrared
spectrafrom
VLT/KMOS,
wemeasurespectraltypes
andextinctionfor32
young low-mass sources. We confirm 13 as brown dwarfs in NGC 2264, with spectral types between
M6 and M8, corresponding
young low-mass sources. We confirm 13 as brown dwarfs in NGC 2264, with spectral types between M6 and M8, corresponding
tomasses between 0.02 and 0.08 M . These are the first spectroscopically confirmed brown dwarfs in this benchmark cluster. 19
to masses between 0.02 and 0.08 M! . These are!the first spectroscopically confirmed brown dwarfs in this benchmark cluster. 19
more
objects
are foundto beM-type
youngstarswithof masses
NGC of2264
with
0.08–0.3
Mdwarfs. 7 of the ofconfirmed
brown
more objects
are foundto be youngstarsM-typeof NGC 2264
0.08–0.3
M!masses! . 7 of the confirmed brown dwarfs
as well
15 15of thehave IR excess
by a disc.
Comparingisochrones,
the typicalageisochrones,of the confirmedaswellas as
ofM-stars
the M-stars
have caused
IR excesscausedby awith
disc.
Comparingwiththe typical age of the confirmed
brown dwarfs is <0.5–5 Myr. More than half of the newly identified brown dwarfs and very low-mass stars have ages <0.5 Myr,brown
dwarfs is <0.5–5 Myr. More than half of the newly identified brown dwarfs and very low-mass stars have ages <0.5 Myr,significantly younger than the bulk of the known cluster population. Based on the success rate of our spectroscopic follow-up, we
significantly
youngerthe brownbulk oftheinknown
Basedthe successrate of our spectroscopic follow-up, weestimate that NGC
2264 hoststhan
200–600
dwarfstotal (in cluster
the given population.
mass range). This
would oncorrespondto a star-to-brown
+0.41
;
these
valuesare correspond to a star-to-brown
dwarf
ratio
between
2.5:1
and
7.5:1.
We
determine
the
slope
of
the
substellar
massfunction
as
α
=
0.43
estimate that NGC 2264 hosts 200–600 brown dwarfs in total (in the given mass range).
This would−0.56
consistent with those measured for other young clusters. This points to a uniform substellar mass function across all star-forming
dwarf
ratio between 2.5:1 and 7.5:1. We determine the slope of the substellar mass function as α = 0.43+0.41−0.56 ; these values areenvironments.
consistent
with those measured for other young clusters. This points to a uniform substellar mass function across all star-forming
Key words: catalogues – surveys – brown dwarfs – stars: low-mass.
environments.
of this cluster has come from several decades of surveys; however,to our knowledge, no brown dwarfs have been spectroscopicallyAs one of the youngest and richest star-forming regions accessible toconfirmed in this benchmark cluster.
deep surveys, NGC 2264 provides a perfect laboratory to study star
The origin of brown dwarfs and the substellar mass function (MF)and brown dwarf formation. Due to its large size of ∼1500 stellar
have long been subjects
debate.
The prerequisite
makingofofthiscluster
has come forfromseveral decades of surveys; however,progress on these issues is to have large and well-characterized
1members
I N T(Teixeira
RO D etUal.C2012;
T I ORapson
N et al. 2014; Venuti et al. 2018),
toourknowledge,
nobrown
dwarfs have been spectroscopicallyrelative proximity of 719 ± 16 pc (Maı́z Apellániz 2019), and low
samples of young brown dwarfs in diverse star-forming regions. NGC
foregroundNGC 2264
been extensively
studiedfor2264 is a diverse
region that
potential to provideAs
one ofextinction,
the youngest
andhasricheststar-forming
regions
accessible
to star-forming
confirmed
in hasthisthebenchmark
cluster.
over60
yr(Herbig
1954)
and
will
remainaprinciple
region
for
star
this
large
samplebut
currently
lacks
thespectroscopic
observations
deep surveys, NGC 2264 provides a perfect laboratory to study star
The origin of brown dwarfs and the substellar mass function (MF)formation studies for the foreseeable future.
needed for detailed characterization. Several purely photometric
and
brown
dwarf
formation.
Due
to
its
large
size
of
∼1500
stellarhave
longdomain,
beenincluding
subjectsof etdebate.
The prerequisite for making
NGC 2264 is hierarchically structured with several subclusters ofsurveys have probed the substellarLammal.
members. Separate
populationsin the cluster
exhibitrange
of agesand Sung
members(Teixeiraet al. 2012;
Rapsonet aal.
2014;
Venuti(2004),
et al. Kendall
2018),et al. (2005),
progresson& Bessell
these (2010).
issuesWeishavetore-have large and well-characterized(1–5 Myr), with evidence for sequential star formation starting incently published the first photometric study identifying brown dwarf
1 I N T RO D U C T I O N

Downloaded from https://academic.oup.com/mnras/article/507/3/4074/6356573 by

Accepted 2021 August 16. Received 2021 August 16; in original form 2021 July 1

ABSTRACTNGC2264の13個のBDを分光同定。M6-M8 (0.02-0.08 Msun)。7個は円盤。⼤体<0.5 Myr。
substellar MF α=0.43。

Universidad Nacional Autónoma de México, Instituto de Ciencias Nucleares, AP 70-543, CDMX 04510, México

An orbital release model for the Orion BN/KL fingers

2 Observatoire de Grenoble, Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France

3 Universidad Nacional Autónoma de México, Instituto de Astronomı́a, AP 70-264, CDMX 04510, México

N ED
ED
IT M
ED A
MN
A U
N S
U C
SC R
RI I
PT PT

Universidad Nacional Autónoma de México, Instituto de Ciencias Nucleares, AP 70-543, CDMX 04510, México

2 Observatoire de Grenoble, Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France

3 Universidad Nacional Autónoma de México, Instituto de Astronomı́a, AP 70-264, CDMX 04510, México

ABSTRACT

We present a simple model in which the bullets that produce the “Orion fingers”(ejected by the BN/KL object)
are interpreted as protoplanets or low mass protostars
ABSTRACTWe
present
a simplein which theexplosion.
bullets that produce
the remnant“Orion fingers”
in orbit around a high mass star that
hasmodela supernova
As theof(ejected by the BN/KL object) are interpreted as protoplanets or low mass protostars
the SN explosion has only ain small
fraction of the mass of the pre-supernova star, theorbit around a high mass star that has a supernova explosion. As the remnant oforbiting objects then movetheaway
in freehastrajectories,
preserving
orbital velocity
SN explosion
only a small fractionof the mass theirof the pre-supernova
star, theorbiting
objects
then
move
away
in
free
trajectories,
preserving
theirorbitalvelocityat the time of release. We atshowthat a system of objects arranged in approximately
the time of release. We show that a system of objects arranged in approximately
co-planar orbits results in trajectories
with inmorphologicaland kinematicalcharacterco-planar orbits results
trajectories with morphologicaland kinematicalcharacteristics
resembling
the
Orion
fingers.
We
show
that,
under
the
assumptionof
constant
istics resembling the Orionvelocity
fingers.
We show that, under the assumption of constantmotions, the positions of the observed heads of the fingers can be used to revelocity motions, the positionsof theobservedof the fromfingers
used resulting
to reconstruct
the propertiesof theheads
orbital structure
whichcanthey beoriginated,inacompact
disk
with
an
outer
radiusof⇠
2.4
AU.
construct the properties of the orbital structure from which they originated, resulting
Key words:
stars:ofwinds,
outflows– ISM: jets and outflows – ISM: individual objects:
in a compact disk with an outerradius⇠ 2.4
AU.
Orion BN/KL

Key words: stars: winds, outflows – ISM: jets and outflows – ISM: individual objects:
Orion BN/KL
1

INTRODUCTION“bullets” at the tips of the fingers might have had a substantial slowing down along their trajectories (Rivera-Ortiz
et al. 2019a, b).
It has been proposed that this sudden event could havebeen:

Downloaded from https://academic.oup.com/mnrasl/advance-article/doi/10.1093/mnrasl/slab072/6328490 by KASI user on 21 Oc

A. C. Raga1? , P. R. Rivera-Ortiz2 , J. Cantó3 , A. Rodrı́guez-González1
A.
Castellanos-Ramı́rez3
1

ownloaded from https://academic.oup.com/mnrasl/advance-article/doi/10.1093/mnrasl/slab072/6328490 b

3
A.
Castellanos-Ramı́rez
1Orion fingersを作る弾丸が超新星爆発した⼤質量星を周る⼩質量原始星だというモデル。
One of the more intriguing flows in the Galactic ISM is com-U

IT

posed of the “fingers” radiating away from the Orion BN/KL
object (a massive embedded stellar object surrounded by acompact nebula, see Becklin & Neugebauer 1967 and Klein1 INTRODUCTION“bullets” at the tips• ofthe fingers might have had a submann & Low 1967). These fingers were first reported bya result of the breakup of a multiple stellar system
slowingalong theirtrajectories(Rivera-Ortiz
Allen & Burton (1993) in IR H2 andstantial[Fe II] emission,and down(see Reipurth
et al. 2010;
Reipurth & Mikkola
2012, 2015;
One of the more intriguing flows in the Galactic
have lengthsISM
of up isto com⇠ 20 (⇠ 7 ⇥ 1017 cm at a distance ofMoeckel&Goddi2012).
The
dynamicsofa
3or 4-body
et al. 2019a, b).
400thepc). Orion
The basesof these fingers, as well as a multitude
system can explain the high velocities of the stars near the
posed of the “fingers” radiating away from
BN/KL
It hasbeen proposedthat(observed
this sudden
event could
haveof other filaments are detected in interferometric
CO obserBN/KL object
in radio continuumby Rodrı́guez
object (a massive embedded stellar object
surrounded
by aZapata et al. 2017; Bally et al.
vations(Zapata et al. 2009;
et
al.
2005
and
by
Gómezetal.
2005,2008),
andin
principle
been:2017).1967
The COemissionof the individual fingers shows a
could trigger the “interstellar bullets that create the Orioncompact nebula, see Becklin & Neugebauer
andKlein-