2023/01/20

星形成ゼミ
The Star Formation Newsletter 357
徳田一起 (九州大学/国立天文台)
51~65
51

Molecular Fraction in the Galactic Center: The Central Molecular and HI Zones

52

StraKLIP: A novel pipeline for detection and characterization of close-in faint compan- ions through Karhunen-Loêve Image
Processing algorithm

53

Rogue planets and brown dwarfs: Predicting the populations of free-floating planetary mass objects observable with JWST54

ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions – XII: Fragmentation and multi-scale gas
kinematics in protoclusters G12.42+0.50 and G19.88- 0.53

55Core orientations and magnetic fields in isolated molecular clouds

56

Bird’s eye view of molecular clouds in the Milky Way: II. Cloud kinematics from sub-pc to kpc scales

57

The imprint of star formation on stellar pulsations

58

Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS): Scattered light detection of a possible disk wind in RY
Tau

59

Physical properties of accretion shocks toward the Class I protostellar system Oph-IRS 44 (自身の研究の比較込み)

60

Multi-wavelength Observations of MWC 297: Constraints on Disk Inclination and Mass
Outflow

61

Confirmation of the outflow in L1451-mm: SiO line and CH3OH maser detections (自身の研究の比較込み)

62

ALMA uncovers highly filamentary structure towards the Sgr E region

63*

Discovery of Line Pressure Broadening and Direct Constraint on Gas Surface Density in a Protoplanetary Disk

64*

Directly Detecting the Envelopes of Low-mass Planets Embedded In Protoplanetary Discs and The Case For TW Hydrae

65

RVSPY – Radial Velocity Survey for Planets around Young Stars. Target characteri- zation and high-cadence survey*はこのゼミの参加者の方が共著に含まれていたもの

54.

- ALMAの3mm 帯観測 G12.42+0.50とG19.88-53 (protocluster 領域)- ビリアルパラメータ(α_vir)が2より小さく、重力崩壊中- thermal Jeans fragmentation とconsistent- フィラメントの速度勾配と複数のアウトフローが見られた- astrodendroでブランチ(~0.1 pc)とリーフ(0.03 pc)を同定=> ブランチはLarson則とconsistent な乱流, リーフはtransonic/subsonic
リーフ構造はLarson則から外れている。
スケール依存の乱流と重力の組み合わせが大質量星形成において重要

G12.42+0.50(d~2.4 kpc)

G19.88-0.53(d~3.3 kpc)

54.(の続き)

H13CO+のpeak速度55.
分子雲コアの伸びている方向と磁場を調べた
天体: L1512, L1523, L1333, L1521E, L1544, L1517, L1780 and L183
観測: Herschel column density map, Planck と光学望遠鏡*の偏光観測
結果：コアの方向と磁場の方向はランダムだった
mass-to-flux ratio: ほとんどはcritical だがL1333, L1521E and L183は磁場が強い*ARIES Imaging Polarimeter on 1.04 m Sampurnanand Telescope (ST) at Nainital, India

ハーシェル
map or 土橋厳光に黄色線(Planck)
青線: H-band偏光
黒楕円: dendrogramコア

59.

目的: S系分子でアクリーションショックなどを見たい
観測: ALMAで0“.1 (=14 au) の観測, Oph-IRS 44 (also know YLW 16A)
分子種: SO, SO2, and 34SO => RADEX モデリングで物理状態を調べた
結果- 30 au 以内のinfalling-rotating運動をトレース- 30-50 au で赤方偏移のみ見られた(<=noケプラーモーション?) 。
- より冷たい成分は~400 au離れた位置。
- 密度10^8 cm^-3, >70 K, 柱密度0.4-1.8 x 10^17 cm^-2- SO2/SO>1 でgas-phase のSI2のアバンダンスを増加させる
結論
SO2 はアクリーションショックをトレースしていそう。

観測天体: Oph-IRS 44 (in L1688)- protobinary with a separation of 0.“3HSTやVLT等の観測に基づく(らしいが、ALMAではミリ波源はsingle?)
Class I, d=139 pc, Tbol ~280 K,
Lbol ~7.1 Lo, Menv~0.051 Mo

観測ライン

59. (続き1)0.87 mm

単一鏡観測のアウトフローの向きとは合ってないM(gas+dust) = 4x10^-3 Mo
binary componentなし

赤方偏移の方がちょっと広がっている(Localized streamer か？)59. (続き2)回転+infall モデル(M*1.5)

centrifugal barrier内の外側はケプラーモーション以外(disk-envelope構造)の力学に強く影響を受ける(=>大屋さんらの論文)

おまけ single-dishのアウトフロー

Van der Marel+13

おまけ アウトフローのALMAアーカイブデータ解析(九大 山崎くん)

これ6"#$%&'()*+,-)&' &($-./$&0-(1&2 )'$3"45"6++7$8)9 1)'/ ,':$%;39;$+,</*$:/-/=-)&'<
概要- L1451-mmはペルセウスにある有力なファーストコア候補(e.g., Maureira et al. 2020)=> 低速度COアウトフロー + コンパクトミリ波源 (Pineda+11) 等- NOEMA 干渉計(+ IRAM 30m)で3mm帯のいろんなラインを観測*- SiO とメタノール(のメーザー)を検出- ショックで説明可能(H2 density of ∼ 3 × 106 cm−3 and a temperature higher than 40 K)- ファーストコアモデルでは20 Kくらいのショックしか予想されていない=> アウトフローは実は天球面上に近く、もっと速度は早いかも？

*分解能~1."5 (~400 au at 282 au)検出できた分子種/トランジション
C-C3H2, CH3OH, SiO, CS, SO, H2CO, HC3N, NDCO, DCN, DCO+=>このうちH2CO, CS, and SiO lines はアウトフローらしい6"#$>の続き"?

SiOとメタノールは干渉計とIRAMのFluxがほぼ同じ
H2CSとCSは広がったものがフィルターアウトされるファーストコア候補天体~あの人は今*~*2000年後半くらいに発見(と主張される)論文ブーム

Perseus
Chamaeleon
PerseusMC27/L1521F VeLLO

Taurus0.2 M☉のClass 0 protostar? (e.g, Tokuda+17)
Maureira et al. 2020の表より一部改変~14天体中10天体ほどは候補外と認識されつつある
MC35は全く除外されていない

MC35-mmをさらに推せる点
・最近傍(~140pc)天体で、ACA観測しか行われていない(12m arrayで更なる高解像度観測が実行可能)4

ファーストコア候補天体: MC35-mm
Fujishiro et al.

Spitzerの観測

速度~5 km/s のCOアウトフローカラー: 1.3mm
コントア: CO(2-1)

Fujishiro,Tokuda 2020*と思われる
Figure 2. (a) Integrated intensity
distributions of数千年程度
the blueshifted andredshifted velocity c
力学的時間:
are shown by the contours superposed on the 1.3 mm image in the pseudo-color and b* subsequent
短いタイムスケールのため、たくさん観測しないと見つからない
contour levels are 3σ and 6σ, respectively. The contour sequences of blue
and[0.6, 0.8, 1.0, 1.2] (K km s−1 ), respectively. 4 The
dashed black line indicates where
統計的に予想されるライフタイム(<10yr)と無矛盾
Note that the primary beam attenuation is not corrected for the display purpose. The

Molecular Fraction in the Galactic Center: The Central Molecular and HI Zones

Yoshiaki Sofue F By mapping the molecular fraction of the Galactic Center (GC), we quantitatively address the question of
how much molecular and central the CMZ (Central Molecular Zone) is. For this purpose we analyze the CO and HI-line archival⇢⌃
data, and determine the column- (surface-) and volume-molecular fractions, fmoland fmol, which are the ratio of column-mass
density of H2 projected on the sky to that of total gas (H2 + HI) from the line intensities, and the ratio of volume-mass densities⌃of H2 to total gas from the brightness temperature, respectively. It is shown that fmol is as high as ⇠ 0.9 0.95 in the CMZ, and⇢fmol
is 0.93 0.98 in the GC Arms I and II attaining the highest value of ⇠ 0.98 toward Sgr B2. The expanding molecular ring⌃⌃
(EMR, or the parallelogram) has a slightly smaller fmol
as ⇠ 0.9 0.93. We define the CMZ as the region with fmol
0.8 0.9
between the shoulders of plateau-like distribution of H2 column density from l = 1 .1 to +1 .8 having Gaussian vertical
distribution with a half thickness of ±0 .2. The CMZ is embedded in the Central HI Zone (CHZ), which is defined as an HI
disc between l ⇠ 2 and +2 .5, b = 0 .5 and +0 .5. Based on the analysis, we discuss the origin of CMZ and interstellar⇢⌃
physics such as the volume filling factors of molecular and HI gases inferred from the diﬀerence between fmoland fmol.

StraKLIP: A novel pipeline for detection and characterization of close-in faint companions through Karhunen-Loêve Image Processing algorithm
Giovanni M. Strampelli, Laurent Pueyo, Jonathan Aguilar, Antonio Aparicio, Gaspard Duchêne, Massimo
Robberto F We present a new pipeline developed to detect and characterize faint astronomical companions at small angularseparation from the host star using sets of wide-field imaging observations not specifically designed for High Contrast Imaging
analysis. The core of the pipeline relies on Karhunen-Loêve truncated transformation of the reference PSF library to perform

PSF subtraction and identify candidates. Tests of reliability of detections and characterization of companions are made throughsimulation of binaries and generation of Receiver Operating Characteristic curves for false positive/true positive analysis. The
algorithm has been successfully tested on large HST/ACS and 16
WFC3 datasets acquired for two HST Treasury Programs on theOrion Nebula Cluster. Based on these extensive numerical experiments we find that, despite being based on methods designed
for observations of single star at a time, our pipeline performs very well on mosaic space based data. In fact, we are able todetect brown dwarf-mass companions almost down to the planetary mass limit. The pipeline is able to reliably detect signals
at separations as close as & 0.1” with a completeness of & 10%, or ⇠ 0.2” with a completeness of ⇠ 30%. This approach
can potentially be applied to a wide variety of space based imaging surveys, starting with data in the existing HST archive,near-future JWST mosaics, and future wide-field Roman images.

Rogue planets and brown dwarfs: Predicting the populations of free-floating planetary
mass objects observable with JWST

Aleks Scholz, Koraljka Muzic, Ray Jayawardhana, Lyra Quinlan, James Wurster F Free-floating (or rogue) planets
are planets that are liberated (or ejected) from their host systems. Although simulations predict their existence in substantial
numbers, direct observational evidence for free-floating planets with masses below 5 MJup is still lacking. Several cycle-1
observing programs with JWST aim to hunt for them in four diﬀerent star-forming clusters. These surveys are designed to besensitive to masses of 1-15 MJup (assuming a hot-start formation), which corresponds to spectral types of early L to late T
for the ages of these clusters. If the existing simulations are not wide oﬀ the mark, we show here that the planned programs
are likely to find up to 10-20 giant rogue planets in moderate density clusters like NGC1333 or IC348, and several dozen to
100 in high-density regions like NGC2024 and the Orion Nebula Cluster. These numbers correspond to 1-5% of the totalcluster population; they could be substantially higher if stars form multiple giant planets at birth. In contrast, the number offree-floating brown dwarfs, formed from core collapse ("like stars") is expected to be significantly lower, only about 0.25numberof stars, or 1-7 for the clusters considered here. Below 10 MJup that number drops further by an order of magnitude. We also
show that the planned surveys are not at risk of being significantly contaminated by field brown dwarfs in the foreground or
background, after spectroscopic confirmation. Taken together, our results imply that if a population of L and T dwarfs were to
be found in these JWST surveys, it is expected to be predominantly made up of rogue planets.

ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions – XII:
Fragmentation and multi-scale gas kinematics in protoclusters G12.42+0.50 and G19.880.53

Anindya Saha, Anandmayee Tej, Hong-Li Liu, Tie Liu, Namitha Issac, Chang Won .5(-)-381.4(u4.i)0.4(e)-379.82(a(p264(t)n)(W)918(e)0.981(e)0.4(.)-0.4(s)380.m)0.7.7S.4o)0..981(e)0.4(eo)0.2(-)-0..987-

Core orientations and magnetic fields in isolated molecular clouds

Ekta Sharma, Maheswar Gopinathan, Archana Soam, Chang Won Lee, T. R. Seshadri F Molecular clouds are sites

Physical properties of accretion shocks toward the Class I protostellar system Oph-IRS
44

E. Artur de la Villarmois, V. V. Guzmán, J. K. Jørgensen, L. E. Kristensen, E. A. Bergin, D. Harsono, N.
Sakai, E. F. van Dishoeck, S. Yamamoto F (Abridged) Physical processes such as accretion shocks are thought to becommon in the protostellar phase, where the envelope component is still present, and they can release molecules from the dust to
the gas phase, altering the original chemical composition of the disk. Consequently, the study of accretion shocks is essential fora better understanding of the physical processes at disk scales and their chemical output. The purpose of this work is to assess
the characteristics of accretion shocks traced by sulfur-related species. We present ALMA high angular resolution observations(0.1") of the Class I protostar Oph-IRS 44. The continuum emission at 0.87 mm is observed, together with sulfur-related species
such as SO, SO2 , and 34 SO2 . Six lines of SO2 , two lines of 34 SO2 , and one line of SO are detected toward IRS 44. The emissionof all the detected lines peaks at 0.1" ( 14 au) from the continuum peak and we find infalling-rotating motions inside 30 au.
However, only redshifted emission is seen between 50 and 30 au. Colder and more quiescent material is seen toward an oﬀset
region located at a distance of 400 au from the protostar, and we do not find evidence of a Keplerian profile in these data.
Accretion shocks are the most plausible explanation for the high temperatures, high densities, and velocities found for the SO2
emission. When material enters the disk–envelope system, it generates accretion shocks that increase the dust temperature anddesorb SO2 molecules from dust grains. High-energy SO2 transitions ( 200 K) seem to be the best tracers of accretion shocks
that can be followed up by future higher angular resolution ALMA observations and compared to other species to assess theirimportance in releasing molecules from the dust to the gas phase.

Multi-wavelength Observations of MWC 297: Constraints on Disk Inclination and Mass
Outflow
William D. Vacca, Göran Sandell F MWC 297 is a young, early-type star driving an ionized outflow and surroundedby warm, entrained dust. Previous analyses of near- and mid-IR interferometric images suggest that the emission at thesewavelengths arises from a compact accretion disk with a moderate (i < 40 degrees) inclination. We have obtained 5-40 micron
images of MWC 297 with FORCAST on SOFIA, as well as near-infrared spectra acquired with SpeX on the IRTF and radio
data obtained with the VLA and BIMA, and supplemented these with archival data from Herschel/PACS and SPIRE. The
FORCAST images, combined with the VLA data, indicate that the outflow lobes are aligned nearly north-south and are well
separated. Simple geometrical modeling of the FORCAST images suggests that the disk driving the outflow has an inclinationof 55 ± 5 degrees, in disagreement with the results of the interferometric analyses. Analysis of the SpeX data, with a wind7
model, suggests the the mass loss rate is on the order of 6.0±3.7
M yr 1 and the extinction to the source is AV ⇠ 8.1±2.5
1.7 ⇥101.5
mag. We have combined our data with values from the literature to generate the spectral energy distribution of the source from
0.35 µm to 6 cm and estimate the total luminosity. We find the total luminosity to be about 7900 L , if we include emission
from an extended region around the star, only slightly below that expected for a B1.5V star. The reddening must be produced
by dust along the line of sight, but distant from the star.

Confirmation of the outflow in L1451-mm: SiO line and CH3 OH maser detections

V. Wakelam, A. Coutens, P. Gratier, T. H G Vidal, N. Vaytet F The observational counterparts of theoretically
predicted first hydrostatic cores (FHSC) have been searched for in the interstellar medium for nearly two decades now. Distinguishing them from other types of more evolved but still embedded objects remains a challenge because these objects havea short lifetime, are small, and embedded in a dense cocoon. One possible lead to finding them is the characterization of theoutflows that are launched by these objects. We observed the L1451-mm FHSC candidate with the NOEMA interferometer inorder to study the emission of several molecules. A nonlocal thermodynamic equilibrium analysis of the CH3 OH detected lines
was performed to retrieve the physical conditions of the emitting region around the central source, together with the CH3 OH,
SiO, CS, and H2 CO column densities. Of the targeted molecules, we detected lines of c-C3 H2 , CH3 OH, CS, C34 S, SO, DCN,
DCO+ , H2 CO, HC3 N, HDCO, and SiO. One of the methanol lines appears to be a maser line. The detection of this class I
maser and the SiO line in L1451-mm support the presence of a low-velocity and compact outflow. The excitation conditions of
the thermal lines of methanol are also compatible with shocks (H2 density of ⇠ 3 ⇥ 106 cm 3 and a temperature higher than
40 K). Although these low-velocity outflows are theoretically predicted by some models of FHSC, these models also predict
the shock temperature to be below 20 K, that is, not evaporating methanol. In addition, the predicted velocities would noterode the grains and release silicon in the gas phase. We therefore conclude that these new observations favor the hypothesisthat L1451-mm would be at a very early protostellar stage, launching an outflow nearly on the plane of the sky with a higher
velocity than is observed.

19

ALMA uncovers highly filamentary structure towards the Sgr E region

J. Wallace, C. Battersby, E. A. C. Mills, J. D. Henshaw, M. C. Sormani, A. Ginsburg, A. T. Barnes, H. P.
Hatchfield, S. C. O. Glover, L. D. Anderson F We report on the discovery of linear filaments observed in CO(1-0) emission
for a ⇠ 20 field of view toward the Sgr E star forming region centered at (l,b)=(358.720 , 0.011 ). The Sgr E region is thought
to be at the turbulent intersection of the ”far dust lane” associated with the Galactic bar and the Central Molecular Zone
(CMZ). This region is subject to strong accelerations which are generally thought to inhibit star formation, yet Sgr E contains
a large number of HII regions. We present 12 CO(1-0), 13 CO(1-0), and C18 O(1-0) spectral line observations from ALMA andprovide measurements of the physical and kinematic properties for two of the brightest filaments. These filaments have widths(FWHM) of ⇠ 0.1 pc and are oriented nearly parallel to the Galactic plane, with angles from the Galactic plane of ⇠ 2 . The
filaments are elongated, with lower limit aspect ratios of ⇠5:1. For both filaments we detect two distinct velocity componentsthat are separated by about 15 km s 1 . In the C18 O spectral line data with ⇠0.09 pc spatial resolution, we find that thesevelocity components have relatively narrow (⇠1-2 km s 1 ) FWHM linewidths when compared to other sources towards the
Galactic center. The properties of these filaments suggest that the gas in the Sgr E complex is being ”stretched” as it is rapidly
accelerated by the gravitational field of the Galactic bar while falling towards the CMZ, a result that could provide insight into
the extreme environment surrounding this region and the large-scale processes which fuel this environment.

Discovery of Line Pressure Broadening and Direct Constraint on Gas Surface Density
in a Protoplanetary Disk

Tomohiro C. Yoshida, Hideko Nomura, Takashi Tsukagoshi, Kenji Furuya, Takahiro Ueda F The gas surface
density profile of protoplanetary disks is one of the most fundamental physical properties to understand planet formation.
However, it is challenging to determine the surface density profile observationally, because the H2 emission cannot be observedin low-temperature regions. We analyzed the Atacama Large Millimeter/submillimeter Array (ALMA) archival data of the COline toward the protoplanetary disk around TW Hya and discovered extremely broad line wings due to the pressure broadening.
In conjunction with a previously reported optically thin CO isotopologue line, the pressure broadened line wings enabled us todirectly determine the midplane gas density for the first time. The gas surface density at ⇠ 5 au from the central star reaches⇠ 103 g cm 2 , which suggests that the inner region of the disk has enough mass to form a Jupiter-mass planet. Additionally,
the gas surface density drops at the inner cavity by ⇠ 2 orders of magnitude compared to outside the cavity. We also found a
low CO abundance of ⇠ 10 6 with respect to H2 , even inside the CO snowline, which suggests conversion of CO to less volatile
species. Combining our results with previous studies, the gas surface density jumps at r ⇠ 20 au, suggesting that the inner region(3 < r < 20 au) might be the magnetorotational instability dead zone. This study sheds light on direct gas-surface-density
constraint without assuming the CO/H2 ratio using ALMA.

Directly Detecting the Envelopes of Low-mass Planets Embedded In Protoplanetary
Discs and The Case For TW Hydrae

Zhaohuan Zhu, Avery Bailey, Enrique Macías, Takayuki Muto, Sean M. Andrews F Despite many methods developed to find young massive planets in protoplanetary discs, it is challenging to directly detect low-mass planets that areembedded in discs. On the other hand, the core-accretion theory suggests that there could be a large population of embedded
low-mass young planets at the Kelvin-Helmholtz (KH) contraction phase. We adopt both 1-D models and 3-D simulations
to calculate the envelopes around low-mass cores (several to tens of M ) with diﬀerent luminosities, and derive their thermal
fluxes at radio wavelengths. We find that, when the background disc is optically thin at radio wavelengths, radio observations
can see through the disc and probe the denser envelope within the planet’s Hill sphere. When the optically thin disc is observedwith the resolution reaching one disc scale height, the radio thermal flux from the planetary envelope around a 10 M core ismore than 10% higher than the flux from the background disc. The emitting region can be extended and elongated. Finally,
our model suggests that the au-scale clump at 52 au in the TW Hydrae disc revealed by ALMA is consistent with the envelopeof an embedded 10-20 M planet, which can explain the detected flux, the spectral index dip, and the tentative spirals. The
observation is also consistent with the planet undergoing pebble accretion. Future ALMA and ngVLA observations may directly
reveal more such low-mass planets, enabling us to study core growth and even reconstruct the planet formation history using
the embedded "protoplanet" population.

RVSPY – Radial Velocity Survey for Planets around Young Stars. Target characteri-Zhaohuan Zhu, Avery Bailey, Enrique Macías, Takayuki Muto, Sean M. Andrews F Despite many methods developed to find young massive planets in protoplanetary discs, it is challenging to directly detect low-mass planets that areembedded in discs. On the other hand, the core-accretion theory suggests that there could be a large population of embedded
low-mass young planets at the Kelvin-Helmholtz (KH) contraction phase. We adopt both 1-D models and 3-D simulations
to calculate the envelopes around low-mass cores (several to tens of M ) with diﬀerent luminosities, and derive their thermal
fluxes at radio wavelengths. We find that, when the background disc is optically thin at radio wavelengths, radio observations
can see through the disc and probe the denser envelope within the planet’s Hill sphere. When the optically thin disc is observedwith the resolution reaching one disc scale height, the radio thermal flux from the planetary envelope around a 10 M core ismore than 10% higher than the flux from the background disc. The emitting region can be extended and elongated. Finally,
our model suggests that the au-scale clump at 52 au in the TW Hydrae disc revealed by ALMA is consistent with the envelopeof an embedded 10-20 M planet, which can explain the detected flux, the spectral index dip, and the tentative spirals. The
observation is also consistent with the planet undergoing pebble accretion. Future ALMA and ngVLA observations may directly
reveal more such low-mass planets, enabling us to study core growth and even reconstruct the planet formation history using
the embedded "protoplanet" population.

RVSPY – Radial Velocity Survey for Planets around Young Stars. Target characteri-and a median distance of 45 pc. We determine for all target stars their basic stellar parameters and present the results of thehigh-cadence RV survey and activity characterization. We achieve a median single-measurement RV precision of 6 m/s andderive the short-term intrinsic RV scatter of our targets (median 22 m/s), which is mostly caused by stellar activity and decays
with age from >100 m/s at <20 Myr to <20 m/s at >500 Myr. We discover six previously unknown close companions withorbital periods between 10 and 100 days, three of which are low-mass stars, and three are in the brown dwarf mass regime. We
detect no hot companion with an orbital period <10 days down to a median mass limit of 1 MJup for stars younger than 500
Myr, which is still compatible with the established occurrence rate of such companions around main-sequence stars. We findsignificant RV periodicities between 1.3 and 4.5 days for 14 stars, which are, however, all caused by rotational modulation due
to starspots. We also analyse the TESS photometric time series data and find significant periodicities for most of the stars.
For 11 stars, the photometric periods are also clearly detected in the RV data. We also derive stellar rotation periods ranging
from 1 to 10 days for 91 stars, mostly from TESS data. From the intrinsic activity-related short-term RV jitter, we derive theexpected mass-detection thresholds for longer-period companions.