SFN #375 1-13
1. Molecular Gas Tracers in Young and Old Protoplanetary Disks 2. Unveiling two expanding stellar groups formed through violent relaxation in The Lagoon Nebula Cluster 3. JWST MIRI/MRS Observations of T Cha: Discovery of a Spatially Resolved Disk Wind 4. A far-ultraviolet-driven photoevaporation flow observed in a protoplanetary disk 5. Complex organic molecules uncover deeply embedded precursors of hot cores 6. The Carbon Isotopic Ratio and Planet Formation 7. Large Fluctuations within 1 AU in Protoplanetary Disks 8. Radio outburst from a massive (proto)star. III. Unveiling the bipolarity of the radio jet from S255IR NIRS3 9. A consistent explanation for the unusual initial mass function and star formation rate in the Central Molecular Zone (CMZ) (10) Episodicity in accretion-ejection processes associated with IRAS 15398-3359 :İİ: MINDS: JWST/NIRCam imaging of the protoplanetary disk PDS 70 (12) Herschel investigation of cores and filamentary structures in L1251 located in the Cepheus flare 13. The classical T Tauri star CI Tau observed with SPIRou: magnetospheric accretion and planetary formation
10. Episodicity in accretion-ejection processes associated with IRAS 15398-3359
E. Guzmán Ccolque, M. Fernández López, M. M. Vazzano, I. de Gregorio, A. Plunkett, A. Santamaría-Miranda ★ The protostar IRAS 15398-3359 is associated with a bipolar molecular outflow ejected in an nearly northeast- southwest (NE-SW) direction which has been extensively studied. It has been suggested previous episodic accretion events by this source. Furthermore, the analysis of the morphology and kinematics of the molecular outflow revealed the presence of four ¹²CO(2-1) bipolar elliptical shock-like structures identified in both lobes. These structures seem to trace different ejections inclined ～10 deg on the plane of the sky from each other.  This led to the hypothesis that the outflow axis likely precesses and launches material episodically. We analyze ALMA archive observations in Band 6, revealing the presence of low-velocity (< 3.5km s−¹) emission from the line ¹²CO(2-1) to the south and north of the protostar.  We study the morphology and kinematics of the gas, which seems to support the hypothesis of a precessing episodic outflow. The ALMA observations reveal a north-south (N-S) outflow most likely associated with the IRAS 15398-3359 protostellar system.  This outflow could be older than the well-studied NE-SW outflow.  The orientation of the N-S outflow is 50 deg - 60 deg on the plane of the sky away from that of the NE-SW outflow. We also analyze the Spectral Energy Distribution of a far away young star and preliminary discard it as the driver of the SE outflow remnants.  The new observations support the hypothesis of strong episodic accretion-ejection events in IRAS 15398-3359, accompanied by dramatic changes in the orientation of its ejection axis, implying that all the outflows in the region may have been driven by the same protostar.
•この低質量原始星にはNE-SW方向へのoutflowが存在
。今回ALMA Band6のデータを用いることでN-S方向の分子流を新たに検出・Morphologyやkinematicsの解析結果から、N-Sの分子流は過去のoutflowの名残•軸が傾いた理由として非等方な降着が過去にあった可能性•円盤から中心星への降着を考える上でoutflowは原始星円盤の角運動量を抜くため重要•実際には揺らいだ(歳差運動する)outflowが観測されている原因:連星系,ディスクの回転軸とoutflowの軸のズレ,非等方的なガスの降着など•天体: IRAS 15398-3359距離153 ± 5pc低質量Class0原始星(質量0.022M 。程度, envelope mass 0.5 ~ 1.2Mኖ観測(アーカイブデータ, project 2019.1.01063.S, P.I: Jinshi Sai) ALMA 7m array, Band 6分解能~8”今回主に使用するのはCO(2-1)結果これまで知られていたNE-SWoutflow, SE lobeに加えN-S方向にもoutflowが存在
Table 1. Outflow parameters. Δν rad = | vsys − νmax | is the outflow spread in radial velocity, where v sys is the systemic velocity and vmax is the velocity up to which it is possible to detect outflow emission over the 3σ threshold. NE-SW outflowと比較してN-S outflowは速度成分は(1/4程度と)ゆっくりで、構造としては(4倍程度)広がっているFig. 1. Blue-shifted and red-shifted integrated emission of ¹²CO (2- 1) toward the IRAS 15398-3359 region. The blue-shifted and red- shifted emission were integrated over the velocity ranges from 2.3 to 4.7  km s-¹ and from 6.2 to 7.4  km s-¹. Blue-shifted and red-shifted contours are represented at 10, 20, 30, 40, 50, 60, 100, and 150 times the rms of 0.15  mJy beam−¹  km s−¹ and 0.1  mJy beam−¹  km s−¹, respectively. The stars indicate the position of IRAS 15398-3359 and  2MASS 15430576-3410004.  The  synthesized  beam  (7':7×4':2, PA=86°) is represented by the black ellipse in the bottom left corner.議長補N-S outflowの起源複数のoutflowは他の天体でも観測されており、連星由来や、単一の天体から別時期に放出された場合が存在この天体には明確な連星系の証拠は無いいつoutflowが出たのか第一次近似としてどちらのoutflowも天球面からの傾きを仮定(i~30°)すると、 NE-SWのdynamic timeが1300年に対しがN-Sは26000年程度。つまり目安としてN-Sは20倍程度古い。(速度がNE-SWと同程度だと4倍程度古い) SE lobeの起源可能性として、SE方向に存在する天体が本天体から飛び出す際の名残->この天体はミリ波での強い放射がなくより進化した星&位置がSE lobeから遠いことから可能性は低め本天体からのejectionによるものFig. 1. Blue-shifted and red-shifted integrated emission of 12CO (2- 1) toward the IRAS 15398-3359 region. The blue-shifted and red- shifted emission were integrated over the velocity ranges from 2.3 to 4.7  km s-¹ and from 6.2 to 7.4  km s-¹. Blue-shifted and red-shifted contours are represented at 10, 20, 30, 40, 50, 60, 100, and 150 times the rms of 0.15  mJy beam−¹  km s−¹ and 0.1  mJy beam−¹  km s−¹, respectively. The stars indicate the position of IRAS 15398-3359 and  2MASS 15430576-3410004.  The  synthesized  beam  (7':'7×4':'2, PA=86°) is represented by the black ellipse in the bottom left corner. Dynamical time scale：10³ – 10 4 yr outflowの軸の傾きの由来大量のガスが非等方的に本天体へ降着実際、中心星周り半径200auあたりまでH¹³CO+が欠乏(Jørgensen et al. 2013) ->過去100-1000yに起きた活発な降着により光度が上昇しH,Oが昇華し破壊か本天体の質量は比較的軽いため、影響を受けやすく結果軸が傾く。その名残として、今もNE-SWoutflowで歳差運動が確認まとめ:新しく見つかったoutflowは過去にこの天体から放出されていた可能性が高く、outflowの向きが違うのは過去の非等方なガス降着を示唆特許文Fig. 1. Blue-shifted and red-shifted integrated emission of 12 CO (2- 1) toward the IRAS 15398-3359 region. The blue-shifted and red- shifted emission were integrated over the velocity ranges from 2.3 to 4.7  km s-¹ and from 6.2 to 7.4  km s-¹. Blue-shifted and red-shifted contours are represented at 10, 20, 30, 40, 50, 60, 100, and 150 times the rms of 0.15  mJy beam−¹  km s−¹ and 0.1  mJy beam−¹  km s−¹, respectively. The stars indicate the position of IRAS 15398-3359 and  2MASS 15430576-3410004.  The  synthesized  beam  (7':7×4':2, PA=86°) is represented by the black ellipse in the bottom left corner.どれぐらいのガスが降ってきたらどの程度outflowの軸が傾くのか知りたいところ
Herschel investigation of cores and filamentary structures in L1251 located in the Cepheus
12. flare
Divyansh Dewan, Archana Soam, Guo-Yin Zhang, Akhil Lasrado, Saikhom Pravash Singh, Chang Won Lee ★ Context: Molecular clouds are the prime locations of star formation. These clouds contain filamentary structures and cores which are crucial in the formation of young stars.  Aims: In this work, we aim to quantify the physical properties of structural characteristics within the molecular cloud L1251 to better understand the initial conditions for star formation.  Methods:  We applied the getsf algorithm to identify cores and filaments within the molecular cloud L1251 using the Herschel multiband dust continuum image, enabling us to measure their respective physical properties. Additionally, we utilized an enhanced differential term algorithm to produce high-resolution temperature maps and column density maps with a resolution of 13.5". Results:  We identified 122 cores in the region.  Out of them, 23 are protostellar cores, 13 are robust prestellar cores, 32 are candidate prestellar cores (including 13 robust prestellar cores and 19 strictly candidate prestellar cores), and 67 are unbound starless cores.  getsf also found 147 filament structures in the region.  Statistical analysis of the physical properties (mass (M), temperature (T), size, and core brightness (hereafter, we are using the word luminosity (L)) for the core brightness) of obtained cores shows a negative correlation between core mass and temperature and a positive correlation between (M/L) and (M/T). Analysis of the filaments gives a median width of 0.14 pc and no correlation between width and length.  Out of those 122 cores, 92 are present in filaments (75.4%) and the remaining were outside them. Out of the cores present in filaments, 57 (62%) cores are present in supercritical filaments ( M line > 16M ⊙ /pc).
• Herschelのデータを用いてL1251のコアやフィラメントを調査
•発見した122コアの内23コアがprotostellar core,32コアがprestellar core, 67コアがunbound core . 147のフィラメント構造を同定・122コアのうち92コアがフィラメント内に存在(75.4％)、そのうち57コアが超臨界フィラメントに存在(62％)いわゆるこれまでのフィラメントパラダイムの描像と整合的.背景Herschelの近傍(<500pc)分子雲の観測から、高密度領域はフィラメント状で、それに沿って星が誕生していることが明らかとなった。->フィラメントから原始星への進化の様子を理解する必要これまでに得られた観測的特徴として・フィラメントは大体10K程度で、その線質量によらず幅は~0.1pc 。大半のprestellar coreは臨界線質量2c 2 /G ~ 16M o /pcを上回るフィラメント天体:L1251 in the Cepheus flare距離340 ± 7pc(Gaia EDR3 Sharma et al. 2022) Cepheus flareにはL1157, L1172/74, L1228, L1241などの星形成雲が存在Di Francesco et al. (2020)観測: Herschel PACS images in 70 and 160 μ m (Poglitsch, A. et al. 2016 e 2: Herschel SPIRE 350 μm image. The elongated structures are highlighted in the Herschel SPIRE images in 250, 350 and 500 μ m (Griffin, M. J. et al. 2010)ビームサイズ: 70-500μmにかけて8.4, 13.5, 18.2, 24.9, and 36.3"コアやフィラメントの同定にはgetsf(Men'shchikov 2021)アルゴリズムを使用長さが0.2pc以上かつS/N>2.5のセレクションをかけた結果Figure 9:  The detected cores overlaid on detected filaments along with their linear densities
Table 1: Number of cores in filaments of varying linear densitiesこれまでのHerschelの結果と整合的コアの間隔等の議論はなし
11. MINDS: JWST/NIRCam imaging of the protoplanetary disk PDS 70
V. Christiaens, M. Samland, Th. Henning, B. Portilla-Revelo, G. Perotti, E. Matthews, O. Absil, L. Decin, I. Kamp, A. Boccaletti, B. Tabone, G. -D. Marleau, E. F. van Dishoeck, M. Güdel, P. -O. Lagage, D. Barrado, A. Caratti o Garatti, A. M. Glauser, G. Olofsson, T. P. Ray, S. Scheithauer, B. Vandenbussche, L. B. F. M. Waters, A. M. Arabhavi, S. L. Grant, H. Jang, J. Kanwar, J. Schreiber, K. Schwarz, M. Temmink, G. Östlin ⭐ Context. Two protoplanets have recently been discovered within the PDS 70 protoplanetary disk. JWST/NIRCam offers a unique opportunity to characterize them and their birth environment at wavelengths difficult to access from the ground.  Aims.  We aim to image the circumstellar environment of PDS 70 at 1.87 µm and 4.83 µm, assess the presence of Pa-α emission due to accretion onto the protoplanets, and probe any IR excess indicative of heated circumplanetary material. Methods. We obtain non-coronagraphic JWST/NIRCam images of PDS 70 within the MINDS (MIRI mid- INfrared Disk Survey) program.  We leverage the Vortex Image Processing (VIP) package for data reduction, and develop dedicated routines for optimal stellar PSF subtraction, unbiased imaging of the disk, and protoplanet flux measurement in this type of dataset.  A radiative transfer model of the disk is used to disentangle the contributions from the disk and the protoplanets.  Results.  We re-detect both protoplanets and identify extended emission after subtracting a disk model, including a large-scale spiral-like feature. We interpret its signal in the direct vicinity of planet c as tracing the accretion stream feeding its circumplanetary disk, while the outer part of the feature may rather reflect asymmetric illumination of the outer disk. We also report a bright signal consistent with a previously proposed protoplanet candidate enshrouded in dust, near the 1:2:4 mean-motion resonance with planets b and c. The 1.87 μm flux of planet b is consistent with atmospheric model predictions, but not that of planet c. We discuss potential origins for this discrepancy, including significant Pa-α line emission. The 4.83 μm fluxes of planets b and c suggest enshrouding dust or heated CO emission from their circumplanetary environment.
PDS70を1.87 μ mと4.83 μ mのJWST/NIRCamで観測してみた
inner diskとouter diskの間のgapで二つの惑星の存在を再確認
(e.g., Keppler et al. 2018; Müller et al. 2018; Christiaens et al. 2019b; Haffert et al. 2019; Isella et al. 2019; Benisty et al. 2021)第3の惑星候補d(Mesa et al.2019)も確認惑星cへのリングからの降着の様子を確認dの位置はbとcのMean-motion resonance(1:2:4)におおよそ対応Fig. G.1. Schematic summary of our proposed interpretation for the main features detected in our NIRCam observation, including an accre- tion stream feeding the circumplanetary disk of planet c , and a proto- planet candidate d at the edge of the inner disk.