SFN #371 48-59
担当：土井 聖明 (総研大D2)
48. VVV-WIT-12 and its fashionable nebula: a four year long period Young Stellar Object with a light echo?
49. Aligned Grains and Scattered Light Found in Gaps of Planet-Forming Disk
50. The RMS survey: a census of massive YSO multiplicity in the K-band
51. JWST imaging of edge-on protoplanetary disks II. Appearance of edge-on disks with a tilted inner region: case study of
IRAS04302+2247
52. Mid-infrared spectra of T Tauri disks: Modeling the effects of a small inner cavity on CO2 and H2O emission
53. Molecular clouds in M51 from high-resolution extinction mapping
54. The role of turbulence in high-mass star formation: Subsonic and transonic turbulence are ubiquitously found at earlystages
55. The Gaia-ESO Survey: 3D dynamics of young groups and clusters from GES and Gaia EDR3
56. A Pathway for Collisional Planetesimal Growth in the Ice-Dominant Regions of Proto- planetary Disk
57. A Systematic Observational Study on Galactic Interstellar Ratio 18O/17O. II. C18O and C17O J=2-1 Data Analysis
58. Exploring the dust grain size and polarization mechanism in the hot and massive Class 0 disk IRAS 16293-2422 B
59. Observing planetesimal formation under streaming instability in the rings of HD 163296

Aligned Grains and Scattered Light Found in Gaps of Planet-Forming Disk

49. Ian W. Stephens, Zhe-Yu Daniel Lin, Manuel Fernandez-Lopez, Zhi-Yun Li, Leslie W. Looney, Haifeng Yang,
Rachel Harrison, Akimasa Kataoka, Carlos Carrasco-Gonzalez, Satoshi Okuzumi, Ryo Tazaki F Polarized(sub)millimeter emission from dust grains in circumstellar disks was initially thought to be due to grains alignedwith the magnetic field. However, higher resolution multi-wavelength observations along with improved models foundthat this polarization is dominated by self-scattering at shorter wavelengths (e.g., 870 µm) and by grains alignedwith something other than magnetic fields at longer wavelengths (e.g., 3 mm). Nevertheless, the polarization signal is
expected to depend on the underlying substructure, and observations hitherto have been unable to resolve polarization
18 located 147.3 ± 0.5 pc away, is the brightest Class I or
in multiple rings and gaps. HL Tau, a protoplanetary disk
Class II disk at millimeter/submillimeter wavelengths. Here we show deep, high-resolution 870 µm polarization
observations of HL Tau, resolving polarization in both the rings and gaps. We find that the gaps have polarization
angles with a significant azimuthal component and a higher polarization fraction than the rings. Our models showthat the disk polarization is due to both scattering and emission from aligned eﬀectively prolate grains. The intrinsic
polarization of aligned dust grains is likely over 10%, which is much higher than what was expected in low resolution
observations ( 1%). Asymmetries and dust features are revealed in the polarization observations that are not seen in
non-polarimetric observations.

HL Tau の ALMA Band 7 (0.87 mm) の高解像度 polarization 観測。画像が綺麗。
The RMS survey: a census of massive YSO multiplicity in the K-band
Robert G. Shenton,
Rebecca J. Houghton, René D. Oudmaijer, Simon P. Goodwin, Stuart L. Lumsden, Evgenia
・polarization
は起源によって異なる偏光パターンを示す。
Koumpia, Maria Koutoulaki F Close to 100 per cent of massive stars are thought to be in binary systems. The・dustalignment：楕円ダストの長軸方向
multiplicity
of massive stars seems to be intrinsically linked to their formation and evolution, and Massive Young
Stellar Objects are key in observing this early stage of star formation. We have surveyed three samples totalling・selfscattering：円盤の短軸方向
hundreds of MYSOs (> 8M ) across the Galaxy from the RMS catalogue, using UKIDSS and VVV point source data,
and UKIRT K band imaging to probe separations between 0.8-9 arcsec (approx 1000-100,000 au). We have used
・リングーギャップを空間分解する偏光観測を行った。
statistical methods to determine the binary statistics of the samples, and we find binary fractions of 64 ± 4 per cent for
・リング：self-scatteringの低い偏光度
the UKIDSS sample, 53±4 per cent for the VVV sample, and 49±8 per cent for the RMS imaging sample. Also we use
the J and K band magnitudes as a proxy for the companion mass, and a significant fraction of the detected systems
・ギャップではdustalignmentによる高い偏光度
have estimated mass ratios greater than 0.5, suggesting a deviation from the capture formation scenario which would
be aligned with random IMF sampling. Finally, we findthat YSOs located in the outer Galaxy have a higher binary・alignmentによるintrinsicな偏光度は> 10%かも(?)
fraction than those in the inner Galaxy. This is likely due to a lower stellar background density than observed towards

イントロ

Figure 2. Degree of polarization -Z12 Z11 of dust grains against scattering angles. The left panel is for the case of l = 3.1 mm and the right panel for l = 870 m m .
The size distribution is assumed to have power law of n (a ) µ a-3.5. The maximum grain sizes are 10 μm, 100 μm, 1 mm, and 1 cm.

・(ミリ波での)円盤偏光の起源
・自己散乱
粒子により散乱された光が偏光することに起因。
円盤内の光が非等方であることで、散乱光が全体として偏光が観測される。
・ダスト整列楕円形のダストの熱放射による偏光
Figure円盤中のダストが整列していることで、全体として偏光が観測される。
3. Polarization P at the scattering angle of 90° and the albedo w = k (k + k ) as a function of maximum grain size. The size distribution is assumed tohave a power law of n (a ) µ a . The wavelengths are assumed to be 3.1 mm for the left panel and 870 m m for the right panel. The arrows indicate the maximum
-3.5

sca

abs

The Astrophysical Journal, 851:55 (6pp), 2017 December 10

sca

grain size that has the most efﬁcient polarization by 90° scattering.

2.5. Anisotropic Radiation Field

Figure 4. Polarization degree times the albedo Pw against the maximum grain
size. This ﬁgure represents a grain size that contributes most to the polarized
intensity. Each line corresponds to the wavelengths of 0.34, 0.87, 3.1, and
7 mm. The band numbers correspond to the ALMA band numbers for eachwavelength.
Table 1
The Detectable Grain Size for Observed Wavelengths

The second condition for producing the polarization due toscattering is the asymmetry in the distribution of the lightsource. In the case of sub-millimeter emission from protoplanetary disks, the light source is the thermal emission of dust
particles. Therefore, its spatial distribution should be anisotropic to produce polarized scattered light. For example, if theincident radiation from one direction is stronger than that fromthe direction different by 90, the ﬁnal scattering is partiallypolarized. Such asymmetry or anisotropy may occur inprotoplanetary disks showing ring-like or lopsided surface
brightness (e.g., Casassus et al. 2013; Fukagawa et al. 2013;
Isella et al. 2013; van der Marel et al. 2013; Pérez et al. 2014).
In this section, we demonstrate that polarization due to selfscattering occurs in such anisotropic radiation ﬁelds by using asimple toy model. Note that the polarization due to scattering of
the anisotropic radiation ﬁeld has been discussed in the context
of E-mode polarization of the cosmic microwave backgroundradiation (e.g., Rees 1968; Kamionkowski et al. 1997;
Seljak 1997).
Hereafter, we ﬁx the maximum grain size and wavelengths

Figure 1. ALMA polarimetric observations at 3.1 mm (top, Kataoka et al.

Figure 1. ALMA
polarimetricobservations
3.1 mmwhere(top,theKataoka
et show
al. the2017),
1.3 mm (middle),
and 870 μmat(bottom),
red vectors
2017), 1.3 mm (middle),
and 870μm (bottom),rednotvectors
show theVector>3σ polarization
morphology(i.e., where
vectors thehavebeen rotated).
lengthsarelinearly
proportional
to
P.
The
color
scale
shows
polarized>3σ polarization morphology (i.e., vectors have not been rotated). theVectorintensity,which
ismasked
to
only
show
3σ
detections.
StokesI
contours
lengths are linearly proportional to P. The color scale shows the polarized inpanel are toshown[3, 10,3σ25,detections.
50, 100, 200,
325, 500,
750, 1000]
intensity, whicheachis masked
onlyforshow
Stokes
I contours
in × sI ,where sI is 44, 154, and 460 μJy bm−1 for 3.1 mm, 1.3 mm, and 870 μm,
each panel are shownfor [3, 10, 25, 50, 100, 200, 325, 500, 750, 1000] × sI ,respectively.
where sI is 44, 154, and 460 μJy bm−1 for 3.1 mm, 1.3 mm, and 870 μm,

観測・ALMA B7 での C-5とC-8 で 18.7 h (on source)

結果
Article16

18°13′58.0″

14

10
8

18°13′57.0″

64

18°13′56.5″
2%

Stokes I 870 μm intensity (mJy per beam)

Fig. 112
18°13′57.5″
画像が重すぎて wiki にアップできないため省略
Dec (J2000)

・偏光度はリング(~1%)よりギャップ(3.7%まで)の方が高い・リングでは短軸向いてるが、ギャップでは軸方向も向いている→ 自己散乱 + ダスト整列

20

4 h 31 min 38.50 s

4 h 31 min 38.45 s

4 h 31 min 38.40 s

RA (J2000)

Fig. 3
画像が重すぎて wiki にアップできないため省略

Fig. 1 | The 870-µm polarization morphology overlaid on the total-intensity
images of HL Tau. The length of the vectors is proportional to the percentage
of light that is polarized (P), with a 2% scale bar shown at the bottom right. A
100 AU scale bar is shown on the bottom left. The vectors are plotted when boththeir total intensity (Stokes I) and the polarized intensity are detected at a 3σ
level, and for P < 10%. Vectors with P < 0.5% are drawn as thinner lines. The
resolution (beam) is shown as a small blue ellipse at the bottom right. Dec,declination; RA, right ascension.

or a
albe
B
asym
of th
to b
Tau
gap
agai
How
the
on t
B
exp
the
sole
ble t
feat
with
gap
ing
the
clos
long
con
effe
tion
scat
over

結果

Fig. 1
画像が重すぎて wiki にアップできないため省略
Ext. Fig. 4
画像が重すぎて wiki にアップできないため省略

Fig. 3
画像が重すぎて wiki にアップできないため省略

51.

JWST imaging of edge-on protoplanetary disks II. Appearance of edge-on disks with atilted inner region: case study of IRAS04302+2247
M. Villenave, K. R. Stapelfeldt, G. Duchene, F. Menard, S. G. Wolﬀ, M. D. Perrin, C. Pinte, R. Tazaki, D.
Padgett F We present JWST imaging from 2µm to 21µm of the edge-on protoplanetary disk around the embedded

young star IRAS04302+2247. The structure of the source shows two reflection nebulae separated by a dark lane. The
source extent is dominated by the extended filamentary envelope at ⇠4.4µm and shorter wavelengths, transitioning at
7µm and longer wavelengths to more compact lobes of scattered light from the disk itself. The dark lane thickness does
not vary significantly with wavelength, which we interpret as an indication for intermediate-sized (⇠ 10µm) grainsin the upper layers of the disk. Intriguingly, we find that the brightest nebula of IRAS40302 switches side between
12.8µm and 21µm. We explore the eﬀect of a tilted inner region on the general appearance of edge-on disks. We findthat radiative transfer models of a disk including a tilted inner region can reproduce an inversion in the brightest
nebula. In addition, for specific orientations, the model also predicts strong lateral asymmetries, which can occur
for more than half possible viewing azimuths. A large number of edge-on protoplanetary disks observed in scattered
light show such lateral asymmetries (15/20), which suggests that a large fraction of protoplanetary disks might host atilted inner region. Stellar spots may also induce lateral asymmetries, which are expected to vary over a significantly
shorter timescale. Variability studies of edge-on disks would allow to test the dominant scenario for the origin of theseasymmetries.

ClassMid-infrared
I edge-onspectra
天体である、IRAS04302+2247のJWST観測
of T Tauri disks: Modeling the eﬀects of a small inner cavity on
CO2 and H2O emission
・NIRCamとMIRIで観測した
Marissa Vlasblom, Ewine F. van Dishoeck, Benoît Tabone, Simon Bruderer F [Abridged] The inner few AU ofdisks around young stars are best probed in the infrared. The James Webb Space Telescope (JWST) is now starting
・<4.4
umではフィラメントでの散乱が中心、>7.7
umではディスクの散乱が中心。その間にdark
to characterize
the chemistry of these regions in unprecedented detail. One
peculiar subset of sources are the so-called
sources”, in which only a strong 15 µm CO2 feature was detected in the spectrum. One scenario that could
lane “CO2-only
explain the weak emission from H2O is the presence of a small, inner cavity in the disk. If this cavity were to extend
・dark laneの幅は波長依存性がない。数umまでのダストは巻き上がっているはず。
・非対称性が波長依存する。これは内側にtilted
diskがあると説明できる。
19

w
im
σ
in
sy
th
sid
lik
a
co
an
no

イントロ
・ダストの沈殿状況は、円盤乱流状態やダストの成長状態の指標として重要

天体：IRAS04302+2247
・とにかくデカいClass 1天体・eDiskでの高解像度観測あり (Lin et al. 2023)
・ダストはミリ波でも巻き上がっている(短軸の非対称性より)
The Astrophysical Journal, 951:8 (26pp), 2023 July 1

Ohashi et al.

2D
ce
ge
w
ex
of
ax
A
an
di
G
ve
(s
th
th
ﬁt

or
Th
ca
br
at
at
B
Th
is
m
sim
et
w

Figure 2. Gallery of the continuum maps obtained in the eDisk program. All maps are shown in the same linear scale (large panels: 640 au × 640 au; medium-size
panels: 320 au × 320 au; small panels: 160 au × 160 au). All the maps are shown in individual asinh-stretch intensity scales, except for IRAS 04169+2702, which isshown in a linear intensity scale. All the map centers are source positions listed in Table 3, except for Ced 110 IRS4, R CrA IRAS 32, and Oph IRS 43, where the map
centers are shifted from the source positions by (0 75, 0 0), (−0 5, 0 5), and (0 0, −0 3), respectively, to show the binary. The beam size and the scale of 20 au
are shown in the lower left and lower right corners of each panel, respectively.

10

Figure 1. The continuum image of IRAS 04302+2247. The white contour
marks the 5σ level (see σ in Table 1). The white ellipse in the lower rightcorner is the beam size (see Table 1), and the length scale is 50 au. The black
plus sign marks the center from the best-ﬁt 2D Gaussian.

zo
th
m
be
ax
ge
fa
th
in
Se
si
ba

観測
・ダストの沈殿状況は、円盤乱流状態やダストの成長状態の指標として重要
The Astrophysical Journal, 961:95 (14pp), 2024 January 20

Villenave et al.

・特徴<4.4 umではフィラメントでの散乱が中心
中心星放射をフィラメントで散乱>7.7 umではディスクの散乱が中心
内側ダスト放射を外側ディスクで散乱
その間にdark laneの幅 d は波長依存性なし
Figure 1. Image gallery of the JWST observations of IRAS04302. All images are shown with a log stretch. The bottom left ellipse in each panel indicates thecorresponding beam size. All images are shown to the same angular scale, and the square box in the 4.44 μm image represents the extent of the 7.7, 12.8, and 21 μm
smaller panels.
umダストは巻き上がっている
Table 1
IRAS04302 Morphological Properties

強度の強い側が入れ替わっている(FR)
円盤自体が長軸方向にずれている(δspines)λ(μm)

F20″×20″
(mJy)

dneb
(arcsec)

FR
W/E

RFWHM
E (arcsec)

RFWHM
W (arcsec)

RFW10%E (arcsec)

RFW10%W (arcsec)

δspines
W-E (%)

2.00(E)
4.44(E)
7.70
12.8
21.0

17 ± 232 ± 316 ± 211 ± 1101 ± 101.35 ± 0.10
1.13 ± 0.10
1.03 ± 0.10
1.10 ± 0.10
0.96 ± 0.10

0.99 ± 0.01
0.58 ± 0.01
0.52 ± 0.01
0.78 ± 0.04
1.34 ± 0.05

2.17 ± 0.25
1.71 ± 0.10
1.35 ± 0.14
1.30 ± 0.16
1.31 ± 0.10

1.75 ± 0.43
1.63 ± 0.15
1.63 ± 0.10
1.43 ± 0.10
1.17 ± 0.10

3.69 ± 0.13
2.97 ± 0.10
2.76 ± 0.10
2.69 ± 0.10
L

3.83 ± 0.17
3.78 ± 0.19
3.57 ± 0.10
3.12 ± 0.15
L

12
11
7
8
L

Note. F20″×20″ are the ﬂux densities integrated over a 20″ × 20″ aperture, dneb the dark lane width, FR the peak ﬂux density ratio of the west over the east nebula,while RFWHM and RFW10% correspond to the radial size of each nebula, respectively measured at 50% or 10% of the peak. δspines characterizes the difference in lateral
centering between both nebulae. At 21 μm, the signal to noise is not sufﬁcient to measure RFW10%. The error bars of dneb, RFWHM, and RFW10% correspond to thestatistical error for the different spine averaging or 0 1, whichever is greater. A positive value of δspines indicates that the west nebula is more centered toward thesouth than the east nebula. (E) indicates that the images are dominated by the envelope; at these wavelengths our measurements might not trace the disk properties.

emission and smooth shape of the two nebulae suggest that, at

ﬂux ratio of the west over the east nebula (FR), radial full width議論・時間変化する blob
2 umのHWSTとHubbleの比較。
16 au/25.5 yr = 3.0 km/s で遠ざかる
low velocity out owの、ダストが溜まったknotかもしれない。
windやjetにしては遅い
The Astrophysical Journal, 961:95 (14pp), 2024 January 20

Villenave et al.

Figure 2. Comparison of the 2.05 μm HST (left panel) and 2.0 μm unconvolved JWST (middle panel), previously aligned images of IRAS04302. The contours
correspond to an intensity level of 5% of the peak (blue is HST, black is JWST), and the white line in the left panel shows the orientation of the normalized cut,displayed in the right panel. A 1D Gaussian was ﬁtted to both cuts (marked in red), and the vertical lines in the right panel indicate the resulting centering of these
Gaussians for each data set.

fldisk is more radially extended than the east side, both at 7.7 andthe older HST images. This is possibly due to time variation of

議論
・強度の強い面の波長依存性と、円盤の位置の長軸方向のずれは、
The Astrophysical Journal, 961:95 (14pp), 2024 January 20
内側に傾いた円盤があると説明できる
The Astrophysical Journal, 961:95 (14pp), 2024 January 20

Villenave et al.

Figure 1. Image gallery of the JWST observations of IRAS04302. All images are shown with a log stretch. The bottom left ellipse in each panel indicates thecorresponding beam size. All images are shown to the same angular scale, and the square box in the 4.44 μm image represents the extent of the 7.7, 12.8, and 21 μm
smaller panels.
Table 1
IRAS04302 Morphological Properties
λ
(μm)
(E)

2.00
4.44(E)
7.70
12.8
21.0

F20″×20″
(mJy)

dneb
(arcsec)

FR
W/E

RFWHM
E (arcsec)

RFWHM
W (arcsec)

RFW10%E (arcsec)

RFW10%W (arcsec)

δspines
W-E (%)

17 ± 232 ± 316 ± 211 ± 1101 ± 101.35 ± 0.10
1.13 ± 0.10
1.03 ± 0.10
1.10 ± 0.10
0.96 ± 0.10

0.99 ± 0.01
0.58 ± 0.01
0.52 ± 0.01
0.78 ± 0.04
1.34 ± 0.05

2.17 ± 0.25
1.71 ± 0.10
1.35 ± 0.14
1.30 ± 0.16
1.31 ± 0.10

1.75 ± 0.43
1.63 ± 0.15
1.63 ± 0.10
1.43 ± 0.10
1.17 ± 0.10

3.69 ± 0.13
2.97 ± 0.10
2.76 ± 0.10
2.69 ± 0.10
L

3.83 ± 0.17
3.78 ± 0.19
3.57 ± 0.10
3.12 ± 0.15
L

12
11
7
8
L

Note. F20″×20″ are the ﬂux densities integrated over a 20″ × 20″ aperture, dneb the dark lane width, FR the peak ﬂux density ratio of the west over the east nebula,while RFWHM and RFW10% correspond to the radial size of each nebula, respectively measured at 50% or 10% of the peak. δspines characterizes the difference in lateral
centering between both nebulae. At 21 μm, the signal to noise is not sufﬁcient to measure RFW10%. The error bars of dneb, RFWHM, and RFW10% correspond to the

Figure 6. Schematic view of the photon propagation in the front half a disk for
two regimes of wavelengths. The observing azimuth corresponds to 270°, andcan reproduce a ﬂux reversal between 12.8 and 21 μm. Forward scattering ismore efﬁcient than scattering in other directions as illustrated by the larger
arrows.

orientations. Such ﬂux reversal occurs for opposite orientationin the mid-infrared, where thermal emission from the inner disk

brighter than
traces the b
Besides, theenhancementof previous s
Lin et al. 2
moderate tilt
We note, hobservationa
is too radia
suggesting ththan in the mdust properti
preparation).
On the ot
model observ
brightest neb
in Section 3.
lateral asymm
perfectly fro
viewing orie
Finally, itthan ∼7.7 μm
envelope is
directly compwavelengths.

5.1. Ti

5.1.1. Ot

The model
a tilted inner
thermal emis

58.

Exploring the dust grain size and polarization mechanism in the hot and massive Class
0 disk IRAS 16293-2422 B

Joaquin Zamponi, María José Maureira, Hauyu Baobab Liu, Bo Zhao, Dominique Segura-Cox, Chia-Lin Ko,
Paola Caselli F Multiwavelength dust continuum and polarization observations arising from self-scattering have beenused to investigate grain sizes in young disks. However, the polarization by self-scattering is low in face-on opticallythick disks and puts some of the size constraints from polarization on hold, particularly for the younger and more
massive disks. The 1.3 mm emission detected toward the hot (&400 K) Class 0 disk IRAS 16293-2422 B has been
attributed to self-scattering, predicting grain sizes between 200-2000 µm. We investigate the eﬀects of grain size inthe resultant flux and polarization fractions from self-scattering using a hot and massive Class 0 disk model andcompare with observations. We compared new and archival high-resolution observations between 1.3 and 18 mm to aset of synthetic models. We have developed a new public tool to automate this process called Synthesizer. This is aneasy-to-use program to generate synthetic observations from numerical simulations. Optical depths are in the range of
130 to 2 from 1.3 to 18 mm, respectively. Predictions from significant grain growth populations, including millimetricgrains are comparable to the observations at all wavelengths. The polarization fraction produced by self-scatteringreaches a maximum of ⇠0.1% at 1.3 mm for a maximum grain size of 100 µm, being an order of magnitude lower
than that observed with ALMA. From the comparison of Stokes I fluxes, we conclude that significant grain growth
could be present in the young Class 0 disk IRAS 16293 B, particularly in the inner hot region (< 10 au, T > 300 K)
where refractory organics evaporate. The polarization produced by self-scattering in our model is not high enoughto explain the observations at 1.3 and 7 mm, and eﬀects like dichroic extinction or polarization reversal of elongatedaligned grains remain other possible but untested scenarios.

Observingplanetesimalformation underBstreaming
instability
in the rings of HD 163296
Class
0 天体の
IRAS 16293-2422の多波長観測+ 偏光観測Francesco Zagaria, Cathie J. Clarke, Richard A. Booth, Stefano Facchini, Giovanni P. Rosotti F We introduce

a new technique to determine the gas turbulence and surface density in bright disc rings, under the assumption that
dust growth is limited by turbulent fragmentation at the ring centre. We benchmark this prescription in HD 163296,
showing that our measurements are consistent with available turbulence upper limits and agree with independent
estimates of the gas surface density within a factor of two. We combine our results with literature measurementsof the dust surface density and grain size to determine the dust-to-gas ratio and Stokes number in the 67 au and
100 au rings. Our estimates suggest that particle clumping is taking place under the eﬀect of streaming instability(SI) in the 100 au ring. Even though in the presence of external isotropic turbulence this process might be hindered,we provide evidence that turbulence is non-isotropic in both rings and likely originating from mechanisms (such asイントロ・Class 0 天体でダストがどれだけ成長しているか？
・光学的に非常に厚いので、長波長観測と、偏光観測からダスト成長を推定

Figure 3. The 14 continuum sources with polarization detections.
ﬂux scale), and the black line segments show the normalized e-vec
arrows indicate the outﬂow position angle, if known (see Section 4

イントロ・Class 0 天体でダストがどれだけ成長しているか？
・光学的に非常に厚いので、長波長観測と、偏光観測からダスト成長を推定

観測
A&A proofs: manuscript no. main

ALMA 1.3 mm (偏光)、ALMA 3 mm、VLA 7 mm (偏光)、VLA 9 mm、VLA 18 mm
0
24 28 32.2

50

Tb (K)
100 150 200

250

ALMA 1.3mm

0100

Tb (K)
200
300

400

0

ALMA 3mm

100

Tb (K)
200
300

VLA 7mm

400

VLA 9mm

050

Tb (K)
100 150 200 250 300

VLA 18mm

Declination (J2000)

32.4
32.6
32.8
33.0
33.2

20 AU

2%
16h 32m 22.64s 22.62s
22.60s
22.58sRight Ascension (J2000)

16h 32m 22.64s 22.62s
22.60s
22.58sRight Ascension (J2000)2%
16h 32m 22.64s 22.62s
22.60s
22.58sRight Ascension (J2000)

20 AU
16h 32m 22.64s 22.62s
22.60s
22.58sRight Ascension (J2000)

Fig. 1. IRAS 16293-2422 B observed at ALMA bands 6 & 3 and VLA bands Q, Ka & Ku, from left to right. Cyan vectors represent polarization
E-vectors (masked out below 3 I and 3 Q ) and the scalebar indicates a level of 2% polarization fraction. The continuum data at 1.3 and 3 mm waspresented by Zamponi et al. (2021) and the 1.3 mm polarization observations were presented by Sadavoy et al. (2018). The polarized continuum
observations at 7 mm were obtained from Liu et al. (2018). 9 mm and 18 mm continuum observations are presented in this work for the first time.
The angular resolution of the observations are: 0.114"⇥0.069" at 1.3 mm (0.18"⇥0.09" for polarized data), 0.048"⇥0.046" at 3 mm, 0.39"⇥0.24"
at 7 mm, 0.12"⇥0.05" at 9 mm and 0.23"⇥0.09" at 18 mm.

10 10organics). The figure shows three panels, one for each maximum
grain size, and tabulated in Table 1 for the 4 observing wavelengths from Fig. 1. For each amax , three di↵erent linestyles rep-モデルとの比較
・流体シミュレーションの結果を元に、偏光の画像を作成。
Joaquin Zamponi et al.: Grain sizes and dust umを作成
polarization in IRAS 16293 Ba̲max = 10 um、100 um(画像)、1000µJy/pixel
10

0

50 100

Stokes I

0.1µJy/pixel
0.0

Stokes Q

20 AUµJy/pixel

0

0.1

2

4 6

Stokes I

nJy/beam
0.02
0.00

Model
1.3 mm

20 AU

20 AU

0.02

nJy/beam
0.02 0.01 0.00 0.01 0.02

Polarization fraction (%)
0.01
0.05 0.10

Model
7 mm

Stokes U

20 AU

Polarization fraction (%)
0.1
1.0

0.1

Stokes U

Stokes Q

20 AU

0.1

µJy/pixel
0.0

20 AU

Fig. 7. Radiative transfer models of self-scattering at 1.3 (top) and 7 mm (bottom) for amax = 100 µm, shown in the upper and lower row,
respectively. Panels illustrate the Stokes I, Q, U fluxes and polarization fraction (with constant-size polarization vectors overlaid) from left to right.

・偏光度は~0.1 %で、観測の値(数%)と全然合わない。
0600
Stokes I
ALMA
Stokes Q
Stokes U
・自己散乱由来ではなさそう
1.3mm
mJy/beam
200400µJy/beam2000200µJy/beam
250
0
250

59.

Observing planetesimal formation under streaming instability in the rings of HD 163296
Francesco Zagaria, Cathie J. Clarke, Richard A. Booth, Stefano Facchini, Giovanni P. Rosotti F We introduce

a new technique to determine the gas turbulence and surface density in bright disc rings, under the assumption that
dust growth is limited by turbulent fragmentation at the ring centre. We benchmark this prescription in HD 163296,
showing that our measurements are consistent with available turbulence upper limits and agree with independent
estimates of the gas surface density within a factor of two. We combine our results with literature measurementsof the dust surface density and grain size to determine the dust-to-gas ratio and Stokes number in the 67 au and
100 au rings. Our estimates suggest that particle clumping is taking place under the eﬀect of streaming instability(SI) in the 100 au ring. Even though in the presence of external isotropic turbulence this process might be hindered,we provide evidence that turbulence is non-isotropic in both rings and likely originating from mechanisms (such as
ambipolar diﬀusion) that could ease particle clumping under SI. Finally, we determine the mass accretion rate under
the assumption that the disc is in steady state and turbulence regulates angular momentum transport. Our results arein tension with spectroscopic measurements and suggest that other mechanisms might be responsible for accretion, in
qualitative agreement with the detection of a magneto-centrifugal wind in this system. Applying our method to larger
samples can be used to statistically assess if SI is a viable mechanism to form planetesimals in bright rings.

・HD 163296 円盤内で Streaming Instability が起きる条件になっているのかを検討

22 Sgas ⎛ u frag ⎞a max º a frag = 0.37
(3 ),3p rs aturb ⎝ cs ⎠2023 December
20
Zagaria et al.
Dv
1Letters,
cs d ln P959:L15 (10pp),Zagariar 20 The Astrophysical Journal
et al.
P=
=,
(2 )
cs
2 v K d ln R
where ρs is the dust material density, ufrag is the velocityof particle
we canStokes
write (Birnstieletal.
number, St,2012)
which describes the degreeofwe can write (Birnstiel et al. 2012)
threshold for dust fragmentation, and αturb regulates theort, which2
determines
the relative
velocity
betweengas
coupling
betweengas andazimuthal
dust;
and
the
pressure
support,
u
2
2 S
frag
gas (iii)
turbulentcollision
velocityof
dust
particles(Ormel
&
⎛
⎞
u
S
2
(3 )
ºv a frag= 0.37,gas ⎛ frag ⎞max=
and dust. HereaΔv
azimuthalvelocity(v)
K − vj is the3gasj⎟ ,a max ºofaafrag(3 )= 0.37
Cuzzi 2007). The Stokes number
compact
particle with ⎜p rs aturb ⎝ cs ⎠(2) deviation from KeplerianDrotation(v
is Pthe locallyrs aturb ⎝ cs ⎠3pEpsteinv1K),cs cds ln
size afrag near the disk midplane can be written in the
P dust= P material= gas-density,(2)
where soundρs is Thetheufragvelocity (10pp),
isothermal
speed,
is thepressure,
and,is Rtheis 959:L15
theAstrophysicalJournalLetters,2023 December 20
Zagaria et al.
regimeascs studies2 (Carrerav Kandd lnR
for dust Recent
fragmentation,
αturb
regulates
where ρs is the dust material density, ufrag is the velocity
disk threshold
radial coordinate.
et al.
2015; thegas
Stfragp a frag rof
p awritefrag rs (Birnstiel et al. 2012)scollision
velocityof number,dust particles&
Yangturbulent
et al. 2017;
Li & Youdin
2021)
showedthat,a(Ormelﬁxed describes
particle
StokesSt,at whichthedegreewecanαturb regulates the= fragmentation,
Stfrag =threshold for dust
.
(4and
)
vj) whichaturb
2 Sgas2 Sgas aturb
2007).
The theStokesnumberofparticlewithrelativeazimuthalvelocity
betweengas
valueCuzzi
ofdeterminesΠ,particle
clumping
under
SIa iscompact
favoredwhen
coupling
between
gas
and
dust;
and
(iii)
the
pressure
support,turbulentcollision
velocity of dust particles S(Ormelu & 2
ally
abut
the disk
midplanecanbegas
writtenin theEpstein2
gas ⎛ frag ⎞
St
≈size
0.1,
itnearrequiresprogressively
largerdust-to-gas
ratios
frag
and
dust.
Here
Δv
=
v
−
v
is
the
azimuthalvelocity(v)
ain
Equation
(3)
and
α
/St
in
Equation
(4)
scale
K
j
j
frag
turb
frag
⎜ with⎟ ,Cuzzi2007).
The
Stokesnumberofacompact
particle
a
a
0.37
(
)
º
=
3
the for smallermax
fragregime asvaluesofKeplerian
St. Steeper pressure
gradients
are also
with the ratio and product of Σgas and αturb, respectively; thus,
deviationfromrotation(v),
clocally
cs ⎠
rs a
3p in
D
v
cs thed ln P
s1 isturbEpstein
15; expected to hinder particle clumping (Johansen etKal. 2007;
⎝
size
a
near
the
disk
midplanecanbewritten
the
frag
Bai
P
=
=
,
(
2
)
combiningthese
expressions
allows us to disentangle the two
a
a
r
r
St
p
p
frag
frag
frag
s
s
isothermal
soundspeed,
Pisthegas
pressure,
and
R
is
the
xed & Stone 2010a;= & Onishi 2018). = cs
StfragSekiya. 2 v K d (ln4) R
regime as
and write an expression
for turbulent
diffusivity
whereρs is the dust material density, ufrag is the velocity
S
a
S
a
2
2
hen disk
gas
turb
gas
turb
radialthatcoordinate.
Recent(Carrera
Evidence
disks frequently
displaystudies
substructuresin dustet al. 2015;
1 2
thresholdfor
dust
fragmentation,andαregulates
the
a
a
r
r
St
turb
ios continuum
u
p
p
frag
frag
frag
a
frag
s
s
emission(Andrews
et
al.
2018;
Long
et
al.
2018;
turb
⎛
⎞
in 2017;Equation
αturb/Stin showed
Equation(4) scaleYangaetLi(3)& andYoudin2021)
that,
at avelocity
ﬁxed between
fragal.
frag relative
which
determinestheazimuthal
gas
0.35
5)
a
=
(velocity==St.dust particles
(4 )
⎜
⎟
turb
frag
turbulentcollisionof(Ormel&lso Andrews
2020)
suggeststhatbright
rings
could
be
sweet
spots
and
α
,
respectively;
thus,
with
the
ratio
and
product
of
Σ
c
St
gas
turb
s
frag
aturb
2 ⎠Sgas2 Sgas aturb
⎝
value
of
Π,
particle
clumping
under
SI
is
favored
when
and
dust.
Here
Δv
=
v
−
v
is
the
gas
azimuthalvelocity(v)
K disentanglejformation
under SI.
Indeed,arej expected
Bai for planetesimalcombining these
expressions
allowsus gapstothe two
Cuzzi 2007). The Stokes number of a compact particle with
Sthalt
≈and
0.1,
but
requiresprogressively
largerdust-to-gas
surface density
toradialdrift,
piling solids
upin bright
rings,
wherethe (vKand
deviation
fromKeplerianrotation),ratios
cgas
write
anitexpression
forturbulent
diffusivity
afrag in Equation
(3)
and
αthe
in Equation(4)written
scale in the Epsteins is the locallyturb/St
frag
size
a
near
disk
midplane
can
be
frag
ratiovalues
mightbestronglyenhanced,favoring
1 2
ust dust-to-gas
for smallerof locally
St. sound
Steeperpressurearealso and with
1 2 P isgradients
isothermal
speed,
thegaspressure,
R
is
the
the
ratio
and
productof Σgas and αturb, respectively; thus,
p
a
c
s
turb
regimeas⎛⎞u
SI-driven
particle
clumping.
This
popularhypothesisisfrag ⎛ aturb ⎞18; expected to hinder
S
=
r
2.85
a
.
(
6
)
⎜
⎟
gas
frag
particle
clumping(Johansen
et
al.
2007;
Bai
s
0.35
5
a
=
(
)
combiningthese
expressions
allowsus
to disentangle the two⎜⎟
diskturbthat
radialRecentstudies(Carrera
et
al.
2015;
(at coordinate.
least
some)
bright
rings
are
2
u
St
frag
frag
ots supported by evidencecs ⎝ Stfrag ⎠
⎝
⎠
a
a
r
r
St
p
p
frag
frag
frag
&
Stone
2010a;
Sekiya&Onishi2018).
s
s
and
write
an
expression
forturbulent
diffusivitypressuretraps(Dullemond
et
al.
2018;
Rosotti
et
al.
2020;
Yang et al. 2017; Li & Youdin 2021) showed
that,
at
a
ﬁxed
ted
= can be =
Stfrag.
(4 )Theseexpressions
show
that
Σ
and
α
gas
turb
et al.
2023)
and ofwassuccessfully
invokedto explain
Evidencethatdisksfrequently
display
substructuresindust
and gassurfacedensity
the Izquierdo
2 Sgas 1 2 aturb
2 Sgas aturb
valueΠ,
particle
clumping
under
SI
is
favoredwhen
determined
from
two
sets
of
parameters:(i)themaximum
optical depthof DSHARP
rings (Stammler
et1al.2 2019).
u frag ⎛ a1/2
ing thecontinuum
emission(Andrews
et
al.
2018;
Long
et
al.
2018;
turb
⎞
a
)
and
the
dust
midplanetemperature
(c
∝
T
),
grain
size
(
max
s
St
≈
0.1,
but
it
requiresprogressively
largerdust-to-gas
ratios
0.35
aturb
= in
(5 )
p for particle
aturb ⎞ in pressure
cs ⎛clumping⎜ (3) ⎟
Even though the conditionsaEquation
and
α
/St
in
Equation(4)
scale
is Andrews
frag
turb
frag
2020)
bright
rings
could
be
sweet
spots
Sgas suggests= 2.85 rthat
a
.
(
6
)
⎜
⎟
which
can
be
measuredusing
highangularresolution
multifragcs ⎝ Stfrag ⎠sverticallyshearing
forstudied
smallerSt.
Steeperpressure
gradients
arealso
are bumps were recently
2usingvalues
u frag ⎝of
Ststratiﬁed
frag ⎠
with theratio
andproduct of Σgas and αturb, respectively; thus,
frequency
dust
continuum
observations,
and
(ii)
the
gas-to-dustforplanetesimalformation
underSI.
Indeed,gaps
areexpected
a number of physical settings (Carrera et al.
20; box simulations inexpected
to solids
hinderparticle
clumping(Johansenet(αal.turb2007;
Bai
/St
,
under
the combining
assumptionthatdustexpressions
radialcoupling
these
allows us to disentangle the two
frag
and
gas
surfacedensityThese
expressions
show
that
Σ
and
α
can
be
to
halt
radialdrift,
pilingupinbrightrings,
where
the
2021,
2022;
Carrera
&
Simon
2022;
Xu
&
Bai
2022a),
no
gas
turb
ain
turbulence,i.e.,expression
αr = αturb). for turbulent diffusivity
diffusivity, αr, is regulated by gasand&Stone
2010a;
Sekiya&Onishi2018).
write
andetermined
from
two
sets
of
parameters:(i)themaximum
directmethodtoobservationallyassessif
SI-drivenplanetesidust-to-gas
ratio
might
be
locally
stronglyenhanced,favoring
1 2.
1/2 This can be inferred from the dust and gas ring widths, the) Evidence
and clumping.
the dust
midplane∝ T ), substructures
grain
sizeparticle(aismaxunderway
formationin thatbrightdisktemperaturerings
has (cbeenp
cs ⎛ aturb ⎞disksfrequently
displayin dustshypothesis
ure mal
1 2 (6 )SI-drivenThis
popularislatterofwhichisderivedfromthegradientoftheazimuthal
S
=
r
2.85
a
.
⎜
⎟
gas
whichyet.
can Scardoni
becontinuum
measured
highproposed
angularresolution
multiet al.using(2021)
thatparticles fragu frag ⎛ aturb ⎞emission(Andrews
et
al.
2018;
Long
et
al.
2018;
ing identiﬁedsupportedbyevidencethat(at least
some)brightrings
are deviations from Keplerian rotation 2(Dullemonduturbvelocity
et=
al.St
frag
frag ⎠
0.35
5
a
(
)
⎜
⎟
frequency
dust
continuum
observations,
and
(ii)
the
gas-to-dustclumping
under
SI
might
have
observableeffects,
reducingthe⎝al.
Andrews
2020)
suggeststhatbrightrings
could
be sweetspots measured from the rotation curve of
2018;
Rosottiet al. 2020),
cs ⎝ Stfrag ⎠pressuretraps(Dullemond
et
al.
2018;
Rosotti
et
al.
2020;
/St
,
under
the
assumption
that
dust
radialcoupling(α
spectraldisk
opticaldepth
andaffectingthe(sub)millimeter
turb
frag
no
These
expressions
show
that Σgas and αturb can bebrightgaps
emissionlines
observed
at high spectral
resolution.
forplanetesimalformation
underSI.
Indeed,are
expected,isregulatedbygas
turbulence,
i.e.,
α
=
α
).
diffusivity,α
index
depending
on
the
size
and
opacityoftheparticles
Izquierdo
et
al.
2023)
and
was
successfully
invokedtoexplainrr
turb
esideterminedfromof density
parameters: (i) the maximum
andtwogas setssurfacetohaltradialdrift,
pilingsolidsupinbrightrings,
where
the
This
can
be
inferred
from
the
dust
and
gas
ring
widths,theformingclumps.
They
also
showedthat
thepresenceof
SIthe
opticaldepthof
DSHARP
rings(Stammleretal.
2019).
een
1/2
3. Results

coupling between gas and dust; and (iii) the pressure support,

イントロ

⎜

⎟

・HD 163296 円盤内で Streaming Instability が起きる条件になっているのかを検討

仮定

⎜

⎟

・HD 163296 円盤内で Streaming Instability が起きる条件になっているのかを検討
・円盤ダストが1. 衝突破壊で成長が止まっている
2. ダスト分布が、乱流拡散と集積の釣り合いに従っている(+先行研究のダストサイズを使用)ことを仮定して、場合には、乱流強度とガス面密度を出し、SIが起きているかを検討した。

(1)

αr/St
(2)

T (K)
(3)

log (a frag cm)(4)

αturb × 104(5)

Σgas (g cm−2)(6)Σdust (g cm−2)(7)

Z × 102(8)

Stfrag × 103
(9)

R100

0.23 ± 0.03
0.04 ± 0.01

21.94 ± 0.10
12.83 ± 0.08

–1.88 ± 0.11
–1.90 ± 0.13

6.09 ± 0.40
3.32 ± 0.42

16.11 ± 4.32
4.98 ± 1.64

0.267 ± 0.002
0.454 ± 0.012

1.66 ± 0.45
9.13 ± 3.02

2.65 ± 0.17
8.31 ± 1.04

結果R67

Note. (1) Ring ID. (2) Dust-to-gas coupling (from Rosotti et al. 2020). (3) and (4) Dust temperature and maximum grain size (from Guidi et al. 2022). (5) Turbulent
The AstrophysicalJournal Letters, 959:L15 (10pp), 2023 December 20
number.
diffusivity. (6) Gas surface density. (7) Dust surface density (from Guidi et al. 2022). (8) Dust-to-gas ratio. (9) Stokes

乱流なしで SI が clumpingを起こすか？

推定された乱流下で SI が clumpingを起こすか？

Table 2Same as Table 1, Using the CO-based Gas Surface Density of Booth et al.
(2019)(1)

Σgas (g cm−2)(2)

Z × 102(3)

Stfrag × 103
(4)

R67
R100

19.20
10.33

1.39 ± 0.01
4.40 ± 0.12

2.22 ± 0.58
4.00 ± 1.22

Note. (1) Ring ID. (2) Gas surface density. (3) Dust-to-gas ratio. (4) Stokes
number.

surface density from Equation (6) and the CO-based estimate of
Booth et al. (2019).
Figure 1. Dust-to-gas ratio and Stokes number of the 67 au (violet) and 100 au(purple) rings of HD 163296 plotted against the threshold for particle clumping
in laminar disks (αturb = 0) of Li & Youdin (2021). Squares display the values
determined using the gas surface densities from Table 1, while circles show
those computed from the gas mass measured by (Booth et al. 2019; see
Table 2). The 100 au ring is prone to particle clumping under SI.

(Mg0.7Fe0.3SiO3; Dorschner et al. 1995), 15% amorphous
carbon (Zubko et al. 1996), and 25% porosity by volume and a
fragmentation velocity ufrag = 1m s−1, motivated by recent
laboratory experiments (Gundlach et al. 2018; Musiolik &Wurm 2019). Columns (1)–(6) of Table 1 summarize theseparameters and our newly inferred Σgas and αturb.
Independent literature measurements of these quantities canbe used to benchmark our procedure. Flaherty et al. (2017)
estimated the turbulent broadening of CO isotopologue andFigure 2. Same as Figure 1 but showing the threshold for particle clumping of
Li 4.&Discussion
Youdin (2021) corrected for an isotropic turbulence level of
αturb = 3.32 × 10−4. Both rings are stable against SI-driven particle clumping.
However,
we gasstressradialthat turbulence
nonisotropic in R67 and R100, which
Hereafter, we discuss
how thepressureisgradient,leads tosize
less stringent
conditions
for particleour
clumping.
disk turbulence, and particle
distribution
can inﬂuence

results. We also comment on the assumptions we made in ourderivation of the gas surface density and possible implications
Since Rosotti et al. (2020) showed that R67 and R100 are
for disk evolution.
particle traps (corresponding to bump amplitudes larger than
70% in the simulations of Carrera & Simon 2022), the latter
4.1. Pressure Support
scenario seems to be closer to our case, suggesting thatplanetesimals
could
through ingravitational instability
The threshold for particle
clumping
by SIform
we adopted
Figure 1 was estimatedrather
with thana suitestratiﬁed
2D none of the previously
SI ofin verticallythese rings.
However,shearing box simulationswithΠ = 0.05 (Li& Youdinhow
2021).turbulence could affectcited
simulations
considered
However, since the 67
and 100
au rings of
HD 163296
areparticle
clumping.
Instead,our results
are based on thepressure maxima (Rosotti et al. 2020), we should compare our

Verti
(1)
R67
R100

Note. (1) Rin
and vertical v
as in previou

and how
several wo
external tu(MHD) ef
the vertica
even be bescale effec
Xu & B
shearing bof ambipo
formation
under less
especiallydriven pla
AD is activ
clumping