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.
背景• 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

dust
with
We
tors,

VLA 1623-A and VLA 1623-B.

観測• ALMA in Band 6 (1.3 mm)• 空間分解能 ~ 0.25’’ ~ 30 au

stokes I

and t

disk

VLA 1623• @ Ophiuchus ~ 120 pc• Class 0のtriplet (1つはwide)

All p
to 90
angle
appr
U an
posit
a1σ
appr
of th
Fig
of VL
inten
polar
lower
to co
no ro

disk
candidatering

Figure 1. ALMA 1.3 mm Stokes I observations of VLA 1623. The

Fig

polarization vector

peaky
peak ~ -50º
minor axisに 垂 直 に 整 列of the high dens
at levels of -10
km s−1 . On lasion outside of
cating that thesstructures.
For τ > 1,
broad
pected to domi
peak ~ 30ºment (Yang etazimuthal方amined
向に整列
modelsproperties, such
diﬀerent inclina
Pohl et al. 20167
els tend to showby eye2011; Reissl et al. 2014). Hourglass morphologies in paron variations inhe ring.
ticular are expected for contracting clouds with fluxple, face-on disk
an infrozen magnetic fields (e.g., Mestel & Strittmatter 1967;
ization patternn of theMouschovias 1976; Galli & Shu 1993a).
Figure 4. Histograms for polarization position angle. The solid
highly inclined, hasmagnetica Figure 3. The fieldpolarization morphology of VLA 1623. The e-vectors correspond to only
those datawith I > 3 σItoandPI > 4associatedσPI . The with the extended dust
histogramcorresponds
anglesprimarily aligne-vectors
arealso
scaledbythe(debiased)
polarization
fraction.
A
reference
scale
of
P
=
2%
is
given
in
the
lower-rightcorners.
The
F
ring and the open histogram corresponds to angles associated withmakes
background images are (left) Stokes I as shown in Figure 1 and (right) polarized intensity map as shown in Figure 2 for PI > 4 σPI .
(rotatedby 90º)Pohl et al. 2016
the compact, inner protostellar disks. For definitions on how theresoluregions
were defined
the text and5.
Table 1 lists
the positions,fluxes,see
semi-majoraxes Figure(a),al., in as two separate subregions. Figure 5 shows the outline
tions from thessemi-minor axes (b), and position angles of the two prosolved, of these two subregions in black and brown contours on
few percent.
tostellar disks(seeFigure5) basedon Gaussian
to do not subtract
measuredfromNorth
to East.fits Weaﬀset in maps of polarization angle and polarized intensity. We•
innerdisksのpolarizationはself
scatteringと主張
Most of the
produce these boundaries using 4 σPI contours in pothe Stokes I backgrounddata. We fit theleveldisks fromusing theimfitmeasurements.
task inthesewithoptical de
MIRIAD (Sault et al. 1995).
values axisにaligned
for semi-major
• The
minor
d C18 O larized intensity with a slight modification based on thepolarization angle map to separate the disk of VLA 1623axis, semi-minor axis, and position angle have been detostellar
disks
ns. Fig- A from the extended dust ring. We use these regions toconvolved with the beam,witherrors estimatedby the•inner
diskはopticallythick(indexα>2)appearopticallTable decon1
O (2-1) produce the angle distributions in Figure 4 and to dislargest absolute diﬀerence between the best-fit
scattering towa
fromGaussian
Fits to theInner~Protostellar•Results
見積もられるダスト
200µmDisks
vations cuss the polarization structure for the inner protostellar
volved parameters
and
the
range
of deconvolved
paramandfound polad Cycle disks and extended dust ring in the next two sections.
eters when considering the errors in the observed GausVLA 1623-A
VLA 1623-B•
dust
growthのtimescaleと一致
sian
fit
from
imfit.
These
peak
and
flux
errorscorrespondoftheminor ax
an diskRA (J2000) whereas the
16:26:26.396
16:26:26.306
to statistical uncertainties,
observation undels to(2017) also fou(J2000)-24:24:30.72
4.1. The Inner Protostellar Disks
certainties areDec
likely10%. The disk-24:24:30.86
position angle is
150 au.
plane-of-sky po
adecon (arcsec)
0.368 ± 0.041 0.314 ± 0.011(2013)
tically thick dis
bdecon(arcsec) ringのpolarizationは何が原因？
0.188 ± 0.041 0.102 ± 0.020•
outer
r symPA (degree)
75.3 ± 10.0
42.4 ± 2.7
higher fraction• magnetic field 67.0 ±どちらか，もしくは両方
sed onpeak (mJy beam−1 ) 60.6 ± 3.6
1.3
asymmetry sho
flux (mJy)
141.8 ± 5.9
1.9
ties and fractio• radiation
field 127.3 ±だろうと主張
orpholQualitativelya typi• another
The polarization
patternmechanismof both disks shows very uni7-11 inlarization morp
ring isform morphologies
with orientations of roughly −50◦
with the optica
それぞれについて考察
ion, we(see
Figure4)
andmedianpolarization
fractionsof
1.7%.
First, the disk
Figure 8. Magnetic field orientation for the ring around VLA

parable磁場

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 them odelsky 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,
VLA
associatedwithscales quadrant
whereand south-east quad(Andrews
et al. back2009).
we1623
divide theestimated
n u , B u : uniform
groundrant. 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
n 0 : peak density
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
atatemperature
of
20
K,
G
is
the
gravitational
conr 0 : scale length
Figure 10 shows an overlay of the model magnetic fieldstant, µH = 2.33 is the mean molecular mass per freetions of VLA 1623.
background image is the same as 8, where
2 The-1structure(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
A=10 (aspect比) observed b-vectors toward the ring (Figure 8).
estimatedpeak ourdensity.
withsolid 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

重力収縮により磁場が引きずられるモデル
Plummer spheroid (index p=2)◦ringのfluxから平均密度を導出→ (T=20 K, κ=0.024 cm g )10
Bonnor-Ebert球でpeak密度を推定-3 11 shows these relative angles for
Nevertheless, even with our simple assumption of axposition 10
angles.
n0~6x10cmFigure
black ellipse outlines the plane-of-sky shape for the inclined spheroid. The flux tubes are selected to give simi-

輻射場

spacings as the observed
polarized
data (e.g.,followisymmetry, the modellarapproximatestheinferred
b-vector
the ring only. The distribution peaks at roughly 80◦ anding Nyquist sampling within the observed beam). We
morphology. This agreement
that
the emission
decreases sharply at relative angles ! 45◦ , suggestingalso adopt a ratioimplies
of peak density
to backgrounddensityν0 = 60 to approximately match the observed polararound VLA 1623-A ofization
corresponds
to
a
disk
with
evidencethat the Stokes I intensity gradient is primarily perpendirections. As expected for a flux-frozen magnetic
we finda pinchedmorphology.
Since axis
we assumeaof magnetization andfield,thatthemagnetic
field
is pridicular to the polarization pattern. Thus, the observauniform background for our model, this density ratio ishighly direction
idealized and notof
a realisticof the true
marily aligned with thethe description
large-scale,coltions are also consistent with grain alignment from andensity contrast between the disk and dense core envilimated outflow. Undertheassumption
ideal
anisotropic radiation field.
ronment.
The model
should only beof
appliedto theMHD,
inner
regions of VLA 1623 associated with the scales where
this field orientation should
suppress disk formation (e.g.,
we have ALMA observations. The simple model is comscalable,
however, anddifHennebelle & Ciardi pletely
2009;
Machidaetcanal.be adjusted2011).to aSince
ferent density ratio when more data are made available.
Murillo et al. (2013) Figure
identified
rotation
10 shows anKeplerian
overlay of the model
magnetic fieldout Figure 10. Overlay of our model magnetic field with our observations of VLA 1623. The background image is the same as 8, where
structure (Figure 9) rotated by a position angle of 30◦
black vectors are e-vectors and blue vectors are b-vectors. The red
to 180 au toward VLA
and toward
we seea(Figure
resolvedwith our1623-A
observed b-vectors
the ring
8).
solid lines are the same as in Figure 9, but have been rotated to
We
find
good
by
eye
agreement
betweentheobserved
andmatch the position angle of the ring. The black ellipse shows thecompact disk-like structure
towardVLA
1623-B,
ideal
outline of the model spheroid.
modeled plane-of-sky magnetic field orientations, particMHD may not be applicable to full radial extent of
VLA 1623. Recent observations of the Class 0 source
B 335 from ALMA (Maury et al. 2018) are well-matchedwith models of non-ideal MHD collapse. Moreover, nonideal MHD simulations readily produce disk structureswith Keplerian rotation profiles, even in cases with relatively strong magnetic fields (e.g., Tomida et al. 2015;
Masson et al. 2016; Hennebelle et al. 2016; Vaytet et al.
2018). Thus, VLA 1623-A is an excellent candidate to
study the eﬀects of non-ideal MHD in the formation andevolution of a large disk ∼ 200 au in diameter.
As previously stated, our simple model excludes rotation. VLA 1623-A has a large rotating disk that follows a Keplerian profile (Murillo et al. 2013) and rotaFigure 11. Normalized distribution of relative angles between
tion is expected to draw a vertical magnetic field into
the Stokes I intensity gradient and the polarization position angles
for the ring around VLA 1623-A. We consider only those pixels
a toroidal field on < 100 au scales (Tomisaka 2011;
I > 3 σI and PI > 4 σPI associated with the ring (see Figure 5).
Kataoka et al. 2012). Nevertheless, other models suggest that the toroidal component is either localized or• 偏光はstokes I の勾配と垂直になるはず• 大部分は~90º• 輻射場による整列とconsistent• 一方で分布は広がっている→強くalignしていないか他のmechanismも効いている• grain size ~ 80µmが必要
Mechanical grain alignment• gas流の向きにdustが揃う• 早いgas流が必要• outflowが考えられるが向きが違う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 scattering• polarization fractionは小さい• disk minor axisに揃う/リング円盤では動径方向に揃う• サイズ依存性が強い→ 違いそう• 輻射場によるdust整列• 中心星からの輻射による整列をモデ
リング• binaryの片方，VLA 5aからの輻射がメインのときbest fit• 北西部が大きくずれる• spiral likeな形状が再現できない

• 磁場によるdust整列• accreting disk + 磁場モデル（Shual.Magnetic
2007）
F. O. Alveset
et al.:
field in a circumbinary disk around a Class I YSO• k=Bp/Bφ
磁 場 の 向 き （ 偏 光 を 90º 回 転 ）δPA=26.8º σ=9.2º

δPA=25.0º σ=8.1ºδPA=23.4º σ=7.5º• 輻射場による整列も否定はできない
が，観測のspiral
likeな形状と波長依存のなさから磁場整列がもっともらしいδPA=31.0º σ=6.0ºδPA=52.9º σ=7.5ºNbest fit (k=3)

Fig. 8. Left panels show synthetic magnetic field lines (red vectors) plotted on top of observed Band 7 Stokes I contours (5 to 45 mJy beam 1 insteps of 5 mJy beam 1 ), polarized intensity (grey scale with same intensity levels of Fig. 1) and magnetic fields (blue vectors, which are 90 -rotatedwith respect to Fig. 1). The red vectors result from our rotating disk modeling assuming di↵erent k = B p /B values. Fig. 6 is shown in the upper
left panel for reference. The right panels show the residuals from each case, with mean PA = PAPAvalues and standard deviation

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

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

Oﬀset (′′)

60
0
−60

Oﬀset (′′)

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

60
Oﬀset (′′)▼NOEMA results• CLUMPFIND algorithmでclumpを同定• gas to dust mass ratio =150, κv = 0.9 cm2g-1,
H2COから平均温度→ core massとcolumn densityを導出

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

H. Beuther et al.: CORE:
Fragmentation
disk
formation
Fig. 2. Large-scale
overview images forandthe 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.

Table 4. Linear Minimum Spanning Tree Analysis

AU. Smaller-scale disk fragmentation will also be addressed by
the CORE program (see Source
section 3) through the spectral#coresline analysis of high-mass accretion disk candidates (e.g., Ahmadi et al.,subm.).

(e.g., Ahmadi et al. subm., Mottram et al. in prep., Bosco et al. in
prep.).
mean sep min sep max sep

The previous investigations of NGC7538IRS1 andIRAS23151
5
NGC7538S (Beuther et al. 2012, 2013; Feng et al. 2016)
can be considered as IRAS23033
a pilot study for the CORE survey
4
presented here. With an overall sample of 20 high-mass
AFGL2591
3 atstar-forming regions (seesample selection below) observed
uniform angular resolution(∼ 0.3′′ − 0.4′′ ) in the 1.3 mm 4
waveG75.78
length band with NOEMA, we can investigate how (un)typical
S87IRS1
11such fragmentation properties
on core scales are. Fragmentation
signatures to be investigatedS106are, for example, the fragment
2
mass, size and separation distributions, and how they relate to
IRAS21078
20
basic underlying physicalprocesses.

3763of young high-mass
2195 star-forming
5264
Our sample
regions was selected to fulfill several criteria: (a) luminosities > 104 L⊙ indi12185
5124
22616
cating that at least an 8 M⊙ star is forming, (b) distance-limited
to below
6 kpc to ensure8284
high linear resolution(∼1000 AU), (c)
15012
21739
high-declination sources (decl.>24◦ ) to obtain the best possible
4392(implying that3202
uv-coverage
they are either5924
not at all or at mostpoorly4564
accessible with 1728
the Atacama Large
Millimeter Array,
18625
ALMA). Furthermore, only sources with extensive complemen5029 resolution
5029
tary high-spatial
observations 5029
at other wavelengths
were selected to better characterize their overall properties. In
1482
710
2491
this context, the sample is also part of a large e-Merlin project led
by Co-I
Melvin Hoare to1573
characterize the 7247
cm continuum emis3027
sion of the sample at an anticipated spatial resolution of down to
6810
4247
9406
30 mas. The initial luminosity selection was based on luminosity and9175
color-color criteria.
Figure 1 presents
the corresponding
4521
18397
luminosity-color plot. We use the luminosity-color plot as a sam-In this paper, we present
the sample selection, the general
G100.3779
20
survey strategy as well as the observational characteristics. The
G084.9505
8 therest of the paper will then focus on the continuum data andfragmentation propertiesG094.6028
of the sample. The other scientific
4 aspects of this survey will be presented in separate publications

Fig. 11. Core masses versus equivalent radii for all detected cores. The
color-coding shows the distances of the sources. The dashed lines show
constant column density with levels of 1023 , 1024 and 1025 cm−2 fromright to left.

 20000 au ~ 0.1 pc

Fig. 6. Compilation of 1.37 mm continuum images for CORE sample converted to linear resolution elements. The contouring is in 5σ steps (seeCepAHW2
NGC7538IRS9W3H2O
W3IRS4
G108.7575
IRAS23385
G138.2957
G139.9091
NGC7538IRS1
NGC7538S

2
9
7
6
3
3
3
2
1
6

(AU)
2. Sample

(AU)

(AU)

2382
3087
2583
3785
13774
7413
22088
32468

2382
1558
1410
1069
8341
6918
16537
32468

2382
4524
6071
7298
19206
7909
27640
32468

7828

1520

13663

3

but increase in column density with increasing mass, as alreadyshown in Fig. 9.

RE: Fragmentation and disk formation

mass vs column denisty

mass vs mean density
相関なし

Fig. 8. Histograms of masses (top panel) and column densities (bottom
panel) for all detected cores.

more lower-column-density environmental gas. This smoothingslightly decreases the measured column densities with increasing distance. The other way round, increasing the covered areawith distance also increases the measured masses. Hence, part ofthe scatter in Fig. 9 is caused by the distance range of our sample.
For smaller distance bins, the scatter is significantly reduced.
Using the derived equivalent radii of the cores from theclumpfind analysis (Table 5), we can also derive mean densities
for all cores under the assumption of spherical symmetry. Figure
H. Beutheral.: CORE: Fragmentationand disk formation
10 plots these mean densities against
theetcorrespondingcore
masses, againradiuscolor-codedwithdistance.
While
these
averagevstypicallymassbetween 106 and 108 cmTable−3
Linear Minimum Spanning Tree Analysis
densities
rather versus
high, masses, 4.
Fig. 9. Gas
columnaredensities
for all detected cores. The
Fig. 10. Mean core densities versus masses for all detected cores. The
there
is
no
clear
trend
betweenthedensities
andthemasses.
color-coding shows the distances of the sources.
color-coding shows the distances of the sources.
Source#cores mean sep min sep max sep
Taking again the distances into account the scatter is reduced
(AU)
(AU)
(AU)
but identifying trends within distance-limited ranges is still dif•core
massとcolumn
densityに正の相関
IRAS23151
5
3763
2195
5264
ficult.
Hence,
inthissample,thecoredensities
aresimilaroverToestimatethetypicalJeans
fragmentation
lengths andtween mass and average density implies that the core masses
IRAS23033
4
12185
5124
22616
•
距離が遠いとcolumn
densityをunder
the
whole
range
of
observed
core
masses.
Havingacorrelation
masses
for
the
clump
scales,weassumemeandensities ofestimate
should correlate with their sizes, i.e., equivalent radii. Figure
AFGL2591
3
15012
8284
21739
betweenmass
andcolumndensity
but
less
good
correlation
bethe
original
larger-scaleparentalgas
clumpsbetween105 and
11 presents the corresponding data again color-coded with dis• core massをover
estimate
G75.78
4
4392
3202
5924
tance. And indeed mass and size are well correlated for the samS87IRS1
11
4564
1728
18625
fragmentation率とcoremassに相関なし
ple, again much tighter if one looks at limited distance ranges.• S106
2
5029
5029
5029
11
Figure 11 also plots lines of constant column densities between
IRAS21078
20
1482
710
2491
23
25
−2
•
core半径とcoremassに正の相関
10 and 10 cm . While most regions scatter between the
G100.3779
20
3027
1573
7247
1023 and 1024 cm−2 lines, also sub-samples between limited disG084.9505
8
6810
4247
9406
G094.6028
4
9175
4521
18397
tance ranges do not follow constant column density distributions
CepAHW2
2
2382
2382
2382
but increase in column density with increasing mass, as already
NGC7538IRS9
9
3087
1558
4524
shown in Fig. 9.
W3H2O
W3IRS4
G108.7575
IRAS23385
G138.2957
G139.9091
24
25
NGC7538IRS1

7
6
3
3
3
2 -2
1

破線:
column densityが一定（右から1023, 10 , 10 cm ）Fig. 11. Core masses versus equivalent radii for all detected cores. The

2583
3785
13774
7413
22088
32468

1410
1069
8341
6918
16537
32468

6071
7298
19206
7909
27640
32468

the fragmentation properties of the gas clumps.

core separation

resolution elements around 0.3 − 0.4 (Table 3) at distancesof several kpc (Table 1), the linear spatial resolution is below
1000 AU for the most nearby sources (Table 3).
In contrast to likely not resolving all sub-structures within
the regions, we nevertheless observe strong fragmentation in
many targets. In particular, given the above estimated Jeans
length between ∼5500 and 27700 AU (depending on density andtemperature),most regions appear
large scaleのgas密度
105to–fragment
106 cmat-3or below thisthermalJeans
温度 20– length
50 K scale. Alternatively, the cores could haveinitially fragmented on Jeans length scales, and then the fragJeans
length~ 5500 –each27700
au further due to the
ments
could
have approachedother evenJeansbulk
mass
~ 0.3
– 3.5
Msuncollapse of the regions.
ongoingmotionsfromthe global
In→多くのcoreのseparationはJeans
contrast to that, the turbulent Jeans analysis, which
includeslength以下
the turbulent contributions to the sound speed, results in significantly larger mass and length scales (e.g., Pillai et al. 2011;
Wang et al. 2014) than the classical thermal Jeans analysis.

• 乱流を考えると，線は右上に大きく移動
6. →観測とより合わないセンス
Discussion
H. Beuther et al.: CORE: Fragmentation and disk formation
乱流を支持する過去の研究との違い
occurs in general on various spatial scales andFig. 12. Nearest neighbor separation histogram from minimum span- • Fragmentation
mass
star
formation
scenariosarepossibleprocess.
or even interplay
is likely
hierarchicalWithinwith
our CORE project, we• a過去の研究は感度が足りない，
ning tree analysis
each other.
investigate thefragmentation processes on clump scales in highSince the sample isselected to host high-mass protostelmassiveなcoreしか見ていないmassstar-forming
We stages
concentrate
lar objects (HMPOs), the range ofregions.
evolutionary
is not on the dense cen•
若い段階を見ているので，lowbroad. Nevertheless, as discussed in section 2, within the HMPO
category, we cover regions
varying IR-brightness andmasswithcoreがまだ作られていない
luminosity-to-mass ratios. Hence, while evolution is unlikely to

12be the main explanation for the observed fragmentation diversity, it cannot be entirely excluded. Furthermore, as discussed
in the previous subsection, diﬀerent levels of initial turbulence
are also unlikely to be the underlying cause. Other possibilities
to explain the diﬀerent levels of fragmentation are variations in
the initial density profiles and/or variations in the magnetic field
properties. Diﬀerences in the density-α
profiles could also arise
from environmental eﬀects like global collapse where the central gas clumps are continuously fed by some larger-scale cloudenvelope.
Since the whole sample is observed with rather uniform uvcoverages, one wonders whether the amount of missing flux may
be related to density structure of the parental gas clump andby that to the observed fragmentation properties of the cores.
Therefore, we compare a few extreme cases: The two comparably isolated regions AFGL2591 and NGC7538IRS1 (both at• fragmentの多様性について• 進化段階ではない• initial density profile• ρ∝r のαが大きいと，fragment
は少なくなる• magnetic field• 磁場が強いとfragment数は小さくなる
Fig. 13. Fragment masses againstlengthとJeansnearest neighbor separation massの関係
from the
実線と破線はJeans
minimum spanning tree analysis. The full line corresponds to the Jeans
lengths and Jeans masses calculated at 50 K for a density grid be-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.

Planet-driven spiral arms in protoplanetary disks: II.Implications,
Jaehan Bae and Zhaouhuan Zhu••

2.の論文の続き
spiralの特徴から直接観測できないplanetのmassを制限できるという内容

4.

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.

• Galactic Census of High- and Medium-mass Protostars (CHaMP) project• ~ 300のmassive clumpに対してtauやTex，Σ，conversion factor Xを求めた• ほとんどのclumpがdynamically ununiformなことを確認• 遅いaccretionやdispersionが存在• accretion rateはlocalなsurface densityに強く依存