星形成ゼミ 2018/6/29
Star Formation Newsletter#305 44-48, #306 1-5
崔仁士

SFN 305
44. Dust Polarization Toward Embedded Protostars in Ophiuchus with ALMA. I. VLA
1623, Sarah I. Sadavoy et al.
45. Spitzer Light Curves of the Young, Planetary-Mass TW Hya Members 2MASSJ11193254-1137466AB and WISEA J114724.10-204021.3, Adam C. Schneider et al.
46. A universal spin-mass relation for brown dwarfs and planets, Aleks Scholz et al.
47. Extended Millimeter Emission in the HD 141569 Circumstellar Disk Detected with ALMA,
Jacob Aaron White and A.C. Boley
48. New member candidates of Upper Scorpius from Gaia DR1, S. Wilkinson, B. Merin, andP. Riviere-Marichalar
SFN306
1.
2.
3.
4.

5.

Magnetic field in a circumbinary disk around a Class I YSO, F.O. Alves et al.
Planet-driven spiral arms in protoplanetary disks: I. Formation mechanism, Jaehan Baeand Zhaouhuan Zhu
Planet-driven spiral arms in protoplanetary disks: II.Implications, Jaehan Bae andZhaouhuan Zhu
The Galactic Census of High- and Medium-mass Protostars. IV. Molecular Clump
Radiative Transfer, Mass Distributions, Kinematics, and Dynamical Evolution, Peter J.
Barnes et al.
Fragmentation and disk formation during high-mass star formation: The IRAMNOEMA (Northern Extended Millimeter Array) large program CORE, H. Beuther et al.

44. Dust Polarization Toward Embedded Protostars in Ophiuchus with ALMA. I. VLA
1623, Sarah I. Sadavoy et al.

• diskのpolarizationの起源• dust alignment by magnetic field• dust alignment by radiation flux (Tazaki et al. 2017)• self scattering (Kataoka et al. 2015)• diskのpolarizationが何によって起こっているのかを明らかにしたい
emission has a ring-like morphology, although we• ALMAによるOphiuchusの26のClasstended
0/Iのsurvey観測
detectno dips in an azimuthally-averaged intensity profile. We call this region an “extended dust ring” to dis• VLA 1623についてreporttinguish it from the more compact emission centered on
VLA 1623-A and VLA 1623-B.

gas at a temperature of 20 K, G is the gravitational con9
stant, µH = 2.33 is the mean molecular mass per free
we view
the ring as man Hellipsewith anaspect ratioofparticle,is theatomichydrogenmass, and n0 is our
1.7, we incline the spheroid and its associated field lines◦
throughestimateda polar angle ofpeakθ = 54density.
from the plane of thesky towardWe
the lineof sight. The field line
coordinates
qualitatively
matchourin model by eye to the obEquations 4 and 5 are then transformed to give a tilted
servations.
9 shows
hourglassshape. Further Figure
details of thisprocedure ourand matched magnetic fieldthese models
are describedin a forthcoming
structurein theplane ofpublication
the sky for the inclined oblate(Myers et al. 2018, in preparation). We note that ourspheroid.
The
redshow the field lines and themodel polarization
patternagreeswell curves
with the numerical simulations from Kataoka et al. (2012, see their Figblackures 6 and
7). ellipse outlines the plane-of-sky shape for the inclined spheroid.
The flux tubes are selected to give simi5.1.2. Model Results
lar spacings
as theobserveddata (e.g., followTo produce
a realistic model,
we needto estimate polarized
thepeak density
scale heightof the oblate spheroid.
ing andNyquistsampling
withinWethe observed beam). We
approximate the peak density by scaling the mean denadopt
ratio
of density
peaktodensity
to background density
sity of also
the ringby the aratio
of peakmean
density in a critical Bonnor-Ebert sphere. We deterof mean
ν0 =
60 to
approximately
the observed polarmine thedensityof thering from estimates matchof
its total
mass anddirections.
volume. First, wethe the for a flux-frozen magnetic
izationAssubtract
expected
best-fit Gaussians for VLA 1623-A and VLA 1623-B
field,
weourfindmorphology. Since we assume a(see Table
1) from
Stokesa I pinched
continuum observations
using imfit
in MIRIAD.
Second, we use
sourceuniformbackgroundforthisourmodel, this density ratio is
subtracted image to measure the 1.3 mm flux of the ring,
Figure 9. Model magnetic field for an oblate spheroid inclined byidealized
andnotmassa realistic
description
thetrue magnetic field struc54. The red solid linesofshow
the plane-of-sky
S1.3 = highly
0.6 Jy. Third,
we calculate
a totalfor the2
ture assuming the flux pattern is comprised of four concentric flux
ring M = S1.3 d /B(T )κ = 0.1 M⊙ , where d is the distubes.
Thedense
black ellipsecoreshows theoutline of the model spheroid.
densitycontrast
between
the
disk
and
envitance to Ophiuchus, B(T ) the the blackbody function,and κ ronment.
is the dust opacity
permodelunit dust should
and gas mass.
The
only be applied to the inner
2 −1
We assume T = 20 K and κ = 0.024 cm g at 1.3 mm
ularly inthe
the north-west
regionsof Finally,
VLAwe1623
associatedwithscales quadrant
whereand south-east quad(Andrews
et al. 2009).
divide theestimated
rant. There are noticeable departures in the north-east
mass inwe
the ringby thevolume ofobservations.
the oblate spheroid toTheandsouth-west
quadrants,
however.
have
ALMA
simplemodel
iscom- The former is where10−3
get a mean density of ∼ 1 × 10 cm and an adopted
we detect no dust polarization. These deviations may bepletely
be toadjusted
to ofaaxisymmetry.
difpeak densityof ∼ 6scalable,
× 1010 √cm−3 .however,For the scale andlength, canlinked
our assumption
The intensity
we adopt a size of r0 = σ/ 4πGµH mH n0 = 40 au, asdistribution
for the ringis clearly asymmetric, which sugdensity
ratio
when
more data
are madeavailable.
sumingferent
σ is the thermalvelocity
dispersion
for hydrogengests its mass distribution may also be asymmetric.
Figure 10. Overlay of our model magnetic field with our observagas at a temperature
of
20
K,
G
is
the
gravitational
conFigure 10 shows an overlay of the model magnetic fieldstant, µH = 2.33 is the mean molecular mass per freetions of VLA 1623. The background image is the same as 8, where
structure(Figurerotatedby a position angle of 30◦
particle,mH is the atomic
hydrogen9)
mass,
and n0 is ourblack vectors are e-vectors and blue vectors are b-vectors. The red
estimatedpeak ourdensity.
withobserved
b-vectors
towardthering(Figure8).
solid lines are the same as in Figure 9, but have been rotated to
We qualitatively match our model by eye to the obWeFigure
find 9goodby matched
eye agreement
servations.
shows ourmagnetic field between the observed andmatch the position angle of the ring. The black ellipse shows the
structure in the plane of the sky for the inclined oblate
outline of the model spheroid.
modeledplane-of-sky
magneticfieldorientations,particspheroid. The red curves show the field lines and the◦black ellipse outlines the plane-of-sky shape for the inclined spheroid. The flux tubes are selected to give similar spacings as the observed polarized data (e.g., following Nyquist sampling within the observed beam). We
also adopt a ratio of peak density to background densityof ν0 = 60 to approximately match the observed polarization directions. As expected for a flux-frozen magnetic
field, we find a pinched morphology. Since we assume auniform background for our model, this density ratio ishighly idealized and not a realistic description of the true
density contrast between the disk and dense core environment. The model should only be applied to the inner
regions of VLA 1623 associated with the scales where
we have ALMA observations. The simple model is completely scalable, however, and can be adjusted to a different density ratio when more data are made available.
Figure 10 shows an overlay of the model magnetic fieldstructure (Figure 9) rotated by a position angle of 30◦
with our observed b-vectors toward the ring (Figure 8).
We find good by eye agreement between the observed andmodeled plane-of-sky magnetic field orientations, partic-

1.

Magnetic field in a circumbinary disk around a Class I YSO,
F.O. Alves et al.

• diskのpolarizationのメインのメカニズムを知りたい• Class I 原始星 BHB07-11@Pipe Nebula (~ 145 pc) をALMAで観測• Band 3, 6, and 7 (97.5,
233, and 343.5 GHz)
• 分解能: ~0.2’’• Band 3 - 7で同じような
P.A.

偏光の原因• self scatter+,• ./lar+0at+/, fract+/,は小さい• 1+s2 3+,/r a4+sに揃う5リング円盤では動径方向に揃う• サイズ依存性が強い
6 違いそう• 輻射場による17st整列• 中心星からの輻射による整列をモデ
リング• 8+,ar9の片方，:;< =aからの輻射がメインのとき8est f+t• 北西部が大きくずれる• s.+ral l+2eな形状が再現できない

F. O. Alves et al.: Magnetic field in a circumbinary disk around a Class I YSO

δPA=26.8º σ=9.2º

δPA=25.0º σ=8.1ºδPA=23.4º σ=7.5º

δPA=31.0º σ=6.0ºδPA=52.9º σ=7.5º

N

5.
背景

Fragmentation and disk formation during high-mass star formation: The IRAMNOEMA (Northern Extended Millimeter Array) large program CORE, H. Beuther etal.

• cluster内でのhigh-mass star formationについて知りたい• fragmentation, disk formation, outflow, chemical process, and etc.
• high mass coreのsurvey観測を行った（CORE Program）• 本論文ではfragmentationの特徴を決めることを目指している
the IRAM large program CORE
• 20のhigh mass coreをNOEMAで観測• L > 104 Lsun; hosting high mass protostellar objects (HMPOs)• およそpre-hot coreからhot coreか，もう少し進化した段階• 6 kpc以内のcores（~1000 auの分解能を達成できるように）• NOEMAでの観測• 1.3 mm bandでcontinuumとlines
observed lines• 分解能: ~ 0.32’’ – 0.5’’ (~ 1000 au)• 短基線配列も組み合わせ• Maximum recoverable scales: 16’’ – 20’’
• + IRAM 30m for lines (not for continuum)

H. Beuther et al.: CORE: Fragmentation and disk formation

本論文ではcontinuumの結果について議論

H. Beuther et al.: CORE: Fragmentation and disk formation

IRAS23151

IRAS23033

AFGL2591

G075.78S87 IRS1−120

0.25 pc

0.25 pc

0.25 pc

0.25 pc

0.25 pc120

S106

IRAS21078

G100.38

G084.9505

G094.6028

120
60
Oﬀset (′′)

▶targets
コントア: SCUBA 850 µm
カラー: Spitzer, WISE 3.4 - 12 µm

0−60

Oﬀset (′′)

60
0
−60
−120

0.25 pc

0.25 pc

0.25 pc

0.25 pc

0.25 pc

120

CepA HW2

NGC7538 IRS9W3 H2OW3 IRS4

G108.75−1200.25 pc

0.25 pc

0.25 pc

0.25 pc

0.25 pc120

IRAS23385

G138.2957

G139.9091

NGC7538 IRS1

NGC7538 S

Oﬀset (′′)

60
0
−60

H. Beuther et al.: CORE: Fragmentation and disk formation

Oﬀset (′′)

60
0
−60
0.25 pc−120−120 −60

060
Oﬀset (′′)

120

0.25 pc

0.25 pc−120 −60

060
Oﬀset (′′)

120

−120 −60

060
Oﬀset (′′)

120

0.25 pc

0.25 pc−120 −60

060
Oﬀset (′′)

120

−120 −60

060
Oﬀset (′′)

120

Fig. 2. Large-scale overview images for the whole CORE sample. The color-scale show 3-color images with blue, green and red from Spitzer
3.6, 4.5 and 8.0 µm for all sources except IRAS 23033, IRAS21078, G100, G094 and IRAS 23385 for which WISE 3.4, 4.6 and 12 µm data arepresented. Furthermore, W3IRS4 uses Spitzer 3.6, 4.5 µm and MSX 8 µm. The contours show SCUBA 850 µm continuum data (di Francesco et al.
2007; contour levels 20, 40, 60, 80% of the peak emission) for all sources except G100, G084 and G108 where these data do not exist.

AU. Smaller-scale disk fragmentation will also be addressed by
the CORE program (see section 3) through the spectral line analysis of high-mass accretion disk candidates (e.g., Ahmadi et al.,subm.).
The previous investigations of NGC7538IRS1 andNGC7538S (Beuther et al. 2012, 2013; Feng et al. 2016)
can be considered as a pilot study for the CORE survey
presented here. With an overall sample of 20 high-massstar-forming regions (see sample selection below) observed at
uniform angular resolution (∼ 0.3′′ − 0.4′′ ) in the 1.3 mm wavelength band with NOEMA, we can investigate how (un)typicalsuch fragmentation properties on core scales are. Fragmentation
signatures to be investigated are, for example, the fragment
mass, size and separation distributions, and how they relate tobasic underlying physical processes.
In this paper, we present the sample selection, the generalsurvey strategy as well as the observational characteristics. The
rest of the paper will then focus on the continuum data and thefragmentation properties of the sample. The other scientific aspects of this survey will be presented in separate publications(e.g., Ahmadi et al. subm., Mottram et al. in prep., Bosco et al. in
prep.).

2. Sample
Our sample of young high-mass star-forming regions was selected to fulfill several criteria: (a) luminosities > 104 L⊙ indicating that at least an 8 M⊙ star is forming, (b) distance-limited
to below 6 kpc to ensure high linear resolution (∼1000 AU), (c)high-declination sources (decl.>24◦ ) to obtain the best possible
uv-coverage (implying that they are either not at all or at mostpoorly accessible with the Atacama Large Millimeter Array,
ALMA). Furthermore, only sources with extensive complementary high-spatial resolution observations at other wavelengths
were selected to better characterize their overall properties. In
this context, the sample is also part of a large e-Merlin project led
by Co-I Melvin Hoare to characterize the cm continuum emission of the sample at an anticipated spatial resolution of down to
30 mas. The initial luminosity selection was based on luminosity and color-color criteria. Figure 1 presents the corresponding
luminosity-color plot. We use the luminosity-color plot as a sam3

RE: Fragmentation and disk formation

the fragmentation properties of the gas clumps.

core separation

Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft Street, Toledo, OH 43606, USA
3 IPAC, Mail Code 100-22, Caltech, 1200 E. California Boulevard, Pasadena, CA 91125, USA

45. Spitzer Light Curves of the Young, Planetary-Mass TW Hya Members(Received March 17, 2018; Accepted April 20, 2018)

2MASS J11193254-1137466AB and WISEA J114724.10-204021.3,
Adam C. Schneider et al. Submitted to AJ
ABSTRACT
We present Spitzer Space Telescope time-series photometry at 3.6 and 4.5 µm of 2MASSJ11193254 1137466AB and WISEA J114724.10 204021.3, two planetary-mass, late-type (⇠L7) browndwarf members of the ⇠10 Myr old TW Hya Association. These observations were taken in order toinvestigate whether or not a tentative trend of increasing variability amplitude with decreasing surface
gravity seen for L3-L5.5 dwarfs extends to later-L spectral types and to explore the angular momentum evolution of low-mass objects. We examine each light curve for variability and find a rotation+0.081+0.093
period of 19.39+0.33
0.28 hours and semi-amplitudes of 0.798 0.083 % at 3.6 µm and 1.108 0.094 % at 4.5µm for WISEA J114724.10 204021.3. For 2MASS J11193254 1137466AB, we find a single period of+0.0363.02+0.04
0.03 hours with semi-amplitudes of 0.230 0.035 % at 3.6 µm and 0.453 ± 0.037% at 4.5 µm, which
we find is possibly due to the rotation of one component of the binary. Combining our results with 12
other late-type L dwarfs observed with Spitzer from the literature, we find no significant di↵erences
between the 3.6 µm amplitudes of low surface gravity and field gravity late-type L brown dwarfs at
Spitzer wavelengths, and find tentative evidence (75% confidence) of higher amplitude variability at
4.5 µm for young, late-type Ls. We also find a median rotation period of young brown dwarfs (10–300Myr) of ⇠10 hr, more than twice the value of the median rotation period of field age brown dwarfs(⇠4 hr), a clear signature of brown dwarf rotational evolution.
Keywords: stars: brown dwarfs• Spitzerによる2つのbrown dwarfのlight curveを調査
1. INTRODUCTION
temperature by some unknown mechanism. This loss
• 変光から回転周期と変光度合いを求めた
could produce patchy surface coverage, which would reSeveral large-scale
surveys dwarfの観測も含めて議論
have found that infrared• 他の12のL
sult in photometric and spectroscopic variability (Ack-variability is common in L, T, and Y-type brown dwarfs
as evinced by ground-based (Radigan et al. 2014, Wilson et al. 2014) and space-based Spitzer and HST surveys (Buenzli et al. 2014, Metchev et al. 2015, Cush-erman & Marley 2001, Burgasser et al. 2002). Radigan et al. (2014) found that while variability can occur
for a wide range of spectral types, high-amplitude varia-

46. A universal spin-mass relation for brown dwarfs and planets,
Aleks Scholz et al.

• Taurusの18のbrown dwarfsのspinを調査• diskをもつbrown dwarfのspin 周期はdiskなしのものより2倍長い• diskによるbreaking• Taurusでのspin周期は他のより年齢のいった星形成領域でのspin周期より長い• 収縮か角運動量保存のため進化とともにspin-up• 質量に対して回転周期が線形増加することを確認47. Extended Millimeter Emission in the HD 141569 Circumstellar Disk Detected with ALMA,
Jacob Aaron White and A.C. Boley

•
•
•
•

ALMA archive dataからHerbig Ae/Be star
HD 141569の円盤構造を調査
3つの異なるBandのビジビリティにモデルをフィットspectral indexの異なるinner diskとouterdiskでよく説明できる
outer diskの方がよりsteepなgrain size分
布をもつ48. New member candidates of Upper Scorpius from Gaia DR1,
S. Wilkinson, B. Merin, and P. Riviere-Marichalar• Gaia (DR1) のデータからUpper Sco subgroupの新しいメンバーを探す• 固有運動，距離の情報にアプライできるclustering algorithmを用いた手法• 167のmember candidate（78はnew）を同定

2.

Planet-driven spiral arms in protoplanetary disks: I. Formation mechanism,
Jaehan Bae and Zhaouhuan Zhu• planetによるdiskのspiralをシミュレーション

3.

Pl%&'()*+,-'&./0,+%l.%+1/.,&.0+2(20l%&'(%+3.*,/4/5.66.610l,7%(,2&/8.
9%':%& ;%'.%&*.<:%2=:=%& <:=>>?.の論文の続き/0,+%lの特徴から直接観測できない0l%&'(の1%//を制限できるという内容

4.

The Galactic Census of High- and Medium-mass Protostars