星形成ゼミ
The Star Formation Newsletter 345
1~62021/10/01
徳田一起 (大阪府立大学/NAOJ)

1An ALMA study of hub-filament systems
I. On the clump mass concentration within the most massive cores

2Long-term stability of planets in and around binary stars

3

A search for transiting companions in the J1407 (V1400 Cen) system

4

Structured velocity field in the inner envelope of B335: ALMA observations ofrare CO isotopologues

5

The SVS13-A Class I chemical complexity as revealed by S-bearing species.
SOLIS XIII

6

The GRAVITY Young Stellar Object survey VIII. Gas and dust faint inner rings in
the hybrid disk of HD141569

(1)ALMA 3mm連続波の 赤外線暗黒星雲(IRDC)サーベイ (新規)6天体
Spitzer 8μm

これ有名なやつ(e.g., Peretto+13)

ALMA 3mm

Fig1の上半分
サンプルセレクション: 8μmの減光でハブフィラメントが見える
距離は2kpc~3.2kpc (+アーカイブからACA Band7のデータの35天体も持ってきた)
目的: ハブフィラメントシステムがより重たいコアを作るかどうか知りたい(1の続き)解析: デンドログラムによるコア同定
ここら辺ちょっと大きすぎ？
3mmで導出していることが原因か？(私見)半径 v.s. 質量のplot
最も重いコアの質量/クランプの質量
13個
16個 6個

赤外線暗明

28個

7個

ハブ 非ハブ・右側のトレンド
ただ親クランプが太ってるだけ
・左側のトレンド
サンプル不足で強く言えないが、ハブフラメントのほうが大きめのコアを作っているtheir MMC early on during its evolution. As clumps evolve, they grow in mass, but such growth does not lead to the formationof more massive MMCs.

(2)

Long-term stability of planets in and around binary stars

Harry A. Ballantyne, Tore Espaas, Bethan Z. Norgrove, Bethany A. Wootton, Benjamin R. Harris, Isaac L.
Pepper, Richard D. Smith, Rosie E. Dommett, Richard J. Parker F Planets are observed to orbit the componentstar(s) of stellar binary systems on so-called circumprimary or circumsecondary orbits, as well as around the entire binary systemon so-called circumbinary orbits. Depending on the orbital parameters of the binary system a planet will be dynamically stable
if it orbits within some critical separation of the semimajor axis in the circumprimary case, or beyond some critical separation forthe circumbinary case. We present N-body simulations of star-forming regions that contain populations of primordial binaries
to determine the fraction of binary systems that can host stable planets at various semimajor axes, and how this fraction ofstable systems evolves over time. Dynamical encounters in star-forming regions can alter the orbits of some binary systems,
which can induce long-term dynamical instabilities in the planetary system and can even change the size of the habitable zone(s)of the component stars. However, the overall fraction of binaries that can host stable planetary systems is not greatly aﬀectedby either the assumed binary population, or the density of the star-forming region. Instead, the critical factor in determining

2

(3)

以下の星の別のトランジェント天体候補を探した=>見つからなかった
3 に関する天体のツイッターまとめ記事 https://togetter.com/li/1542411

56日

(3の続き)主星(J1407)の情報
・ ~16 Myrの若い星・距離: ~130 pc
・場所: Sco-Cen OB association
・spectral type: K
リングの情報・~3 magの減光 が56日間(2007年)・質量: 60~100 Mjup
・リングの数: 37・大きさ(半径): 0.6 au

この研究で行ったこと別のトランジェント天体を探る
いくつかの地上望遠鏡のデータ(19年相当)を解析
そのためにきちんと主星自身の長周期と短周期の変動を取り除く

長周期: 1981 (+94 – 83) days
短周期: 3.206±0.0002 days
新しいトランジェント天体は見つからなかったperiod. J1407 is confirmed as a young active star with an activity cycle consistent with a rapidly rotating solar mass star. With
the rotational modulation removed, the TLS analysis rules out transiting companions with radii larger than about 1 Jupiter.

(4)

Structured velocity field in the inner envelope of B335: ALMA observations of rare CO
isotopologues
Victoria Cabedo, Anaëlle Maury, Josep Miquel Girart, Marco Padovani F Studying Class 0 objects is very important,as it allows to characterize dynamical processes at the onset of the star formation process, and to determine the physicalmechanisms responsible for the outcome of the collapse. Observations of dense gas tracers allow the characterization of key
kinematics of the gas directly involved in the star-formation process, such as infall, outflow or rotation. This work aims atinvestigating the molecular line velocity profiles of the Class 0 protostellar object B335 and attempts to put constraints on
the infall motions happening in the circumstellar gas of the object. Observations of C17 O (1-0), C18 O (1-0) and 12 CO(2-1) transitions are presented and the spectral profiles are analyzed at envelope radii between 100 and 860 au. C17 O
emission presents a double peaked line profile distributed in a complex velocity field. Both peaks present an oﬀset of0.2 to 1 km s 1 from the systemic velocity of the source in the probed area. The optical depth of the C17 O emission
has been estimated and found to be less than 1, suggesting that the two velocity peaks trace two distinct velocity
components of the gas in the inner envelope. After discarding possible motions that could produce the complex velocity
pattern, such as rotation and outflow, it is concluded that infall is producing the velocity field. Because inside-out
symmetric collapse cannot explain those observed profiles, it is suggested that those are produced by non-isotropic
accretion from the envelope into the central source along the outflow cavity walls.

The SVS13-A Class I chemical complexity as revealed by S-bearing species. SOLIS XIIIALMAによるB335 (Class 0原始星)の観測
・C17O, C18Oのそこそこ分解能 (~1”くらい)obtain a census of S-bearing species using interferometric images, towards SVS13-A, a Class I object associated witha hot corino richin interstellar complex organic molecules.
Methods: We used dataか？
at 3mm and 1.4mm obtained with
・複雑な速度構造を確認=>非対称なcollapse

C. Codella, E. Bianchi, L. Podio, S. Mercimek, C. Ceccarelli, A. Lopez-Sepulcre, R. Bachiller, P. Caselli, N.
Sakai, R. Neri, F. Fontani, C. Favre, N. Balucani, B. Lefloch, S. Viti, S. Yamamoto F Aims: The goal is toIRAM-NOEMA in the framework of the Large Program SOLIS. Results: We imaged the spatial distribution of theline emission of 32SO, 34SO, C32S, C34S, C33S, OCS, H2C32S, H2C34S, and NS. The low excitation (9 K) 32SO lineis tracing the fast collimated jet driven by the nearby SVS13-B. Conversely, the rest of the lines are confined in theinner SVS13-A region, where complex organics have been previously imaged. The non-LTE LVG analysis of SO, SO2,and H2CS indicates a hot corino origin (60-120 au). Temperatures between 50 K and 300 K, and volume densities
larger than 105 cm-3 have been derived. The abundances are in the following ranges: 0.3-6 10 6 (CS), 7 10 9 - 1 10 7(SO), 1-10 10 7 (SO2), a few 10 10 (H2CS and OCS), and 10 10 - 10 9 (NS). The N(NS)/N(NS+ ) ratio is larger than10, supporting that the NS+ ion is mainly formed in the extended envelope. Conclusions: The [H2CS]/[H2CO] ratio
increases with time (from Class 0 to Class II objects) by more than one order of magnitude. This suggests that [S]/[O](5)RAM-NOEMA SOLIS (Seeds Of Life In Space) (Ceccarelli et al. 2017)というラージサーベイ の一環
Aims: S系分子の干渉計イメージングをSVS13-A(Class I object associated with a hot corinorich in interstellar complex organic molecules)で行う
ターゲット分子種: SO, SO, C S, C S, C S, OCS, H2C H2C34S, and NS

90GH連続波
分解能~1."8x1."1

天体についての説明Prototypicalって言っていいのか？
(私見)

205GH連続波
分解能~0."6x0."6(5の続き)Codella et al.: S-bearing molecules in SVS13-Athe chemistry of star forming regions using large observational surveys as well as sampling regions on a Solar Systemscale.

The GRAVITY Young Stellar Object survey VIII. Gas and dust faint inner rings in thehybrid disk of HD141569
GRAVITY Collaboration, V. Ganci et al. F The formation and evolution of planetary systems impact the primordialaccretion disk. HD141569 is the only known pre-main sequence star characterized by a hybrid disk. Observations
probed the outer-disk structure showing a complex system of rings and interferometric observations attempted tocharacterize its inner 5 au region, but derived limited constraints. The goal of this work was to explore with new
high-resolution interferometric observations the properties of the dust and gas in the internal regions of HD141569. We
observed HD141569 on mas scales with GRAVITY/VLTI in the near-infrared at low and high spectral resolution. We
interpreted the visibilities and spectral energy distribution with geometrical models and radiative transfer techniques
to constrain the dust emission. We analyzed the high spectral resolution quantities to investigate the properties of theBr-Gamma line emitting region. Thanks to the combination of three diﬀerent epochs, GRAVITY resolves the innerdusty disk in the K band. Data modeling shows that an IR excess of about 6% is spatially resolved and that the originof this emission is confined in a ring of material located at a radius of 1 au from the star with a width smaller than
0.3 au. The MCMax modeling suggests that this emission could originate from a small amount of QHPs, while large
silicate grain models cannot reproduce at the same time the observational constraints on the properties of near-IRand mid-IR fluxes. The diﬀerential phases in the Br-Gamma line clearly show an S-shape that can be best reproduced
witha gas disk in Keplerian rotation, confined within 0.09 au. This is also hinted at by the double-peaked Br-Gammaemission line shape. The modeling of the continuum and gas emission shows that the inclination and position angleof these two components are consistent with a system showing relatively coplanar rings on all scales.

Measuring the Density Structure of an Accretion Hot Spot

C. C. Espaillat, C. E. Robinson, M. M. Romanova, T. Thanathibodee, J. Wendeborn, N. Calvet, M. Reynolds,
J. Muzerolle F Magnetospheric accretion models predict that matter from protoplanetary disks accretes onto thestar via funnel flows which follow the stellar field lines and shock on the stellar surface leaving a hot spot with adensity gradient. Previous work has inferred diﬀerent densities in the hot spot, but has not been sensitive to theradial density distribution. Attempts have been made to measure this with X-ray observations, but X-ray emission
only traces a fraction of the hot spot and also coronal emission. Here we report periodic ultraviolet and optical light
curves of the accreting star GM Aur that display a time lag of about 1 day between their peaks. The periodicity arises
as the source of the ultraviolet and optical emission moves into and out of view as it rotates along with the star. The
time-lag indicates a diﬀerence in the spatial distribution of ultraviolet and optical brightness over the stellar surface.
Within the framework of the magnetospheric accretion model, th(.)140.8392(ric)1(o)1(e)rice1-1(2(ri((d70(0f)r)-1in)-1f)-1frIs-1(rIs)38 92(ric)1(e1(-3