Star Formation Newsletter No. 353 36-42高橋実道（NAOJ） The disk of FU Orionis viewed with MATISSE/VLTI: first interferometric observations in L and M bands 36 Photoionized Herbig-Haro objects in the Orion Nebula through deep high-spectral res- olution spectroscopy III: HH514 37 NIR spectroscopic survey of protostellar jets in the star forming region IC 1396N 38 The SEDIGISM survey: Molecular cloud morphology. II. Integrated source properties 39 40 An Interferometric View of H-MM1. I. Direct Observation of NH3 Depletion From Bubbles and Filaments to Cores and Disks: Gas Gathering and Growth of Struc- ture Leading to the Formation of Stellar Systems 41 42 Magnetic fields and outflows in the large Bok globule CB 54 Photoionized Herbig-Haro objects in the Orion Nebula through deep high-spectral res- olution spectroscopy III: HH514 We analyze the physical conditions and chemical composition of the photoionized Herbig- Haro object HH 514, which emerges from the proplyd 170-337 in the core of the Orion Nebula. We use high-spectral resolution spectroscopy from UVES at t the Very Large Telescope and IFU-spectra from MEGARA at t he Gran Telescopio de Canarias. We observe two components of HH 514, the jet base and a knot, with n e = (2.3 ± 0.1) × 10 5 cm-3 and n e = (7 ± 1) × 10 4 cm¯³, respectively, both with T e ≈ 9000 K. We show that the chemical composition of HH 514 is consistent with that of the Orion Nebula, except for Fe, Ni and S, which show higher abundances. The enhanced abundances of Fe and Ni observed in HH objects compared with the general interstellar medium is usually interpreted as destruction of dust grains. The observed sulphur overabundance (more than two times solar) is challenging to explain since the proplyd photoevaporation flow from the same disk shows normal sulphur abundance. If the aforementioned S-overabundance is due to dust destruction, the formation of sulfides and/or other S-bearing dust reservoirs may be linked to planet formation processes in protoplanetary disks, which filter large sulfide dust grains during the accretion of matter from the disk to the central star. We also show that published kinematics of molecular emission close to the central star are not consistent with either a disk perpendicular to the optical jet, nor with an outflow that is aligned with it. 37 Orion Nebula中のHH514の位置~ 410pc青字：大質量星白字：原始惑星系円盤HH514は170-337に付随、red-shift (OrionのHHはblue-shiftが多い) Fe, Niのラインで明るい多くのHHではFe, Niのabundance大ダストの破壊によって供給（？） Orionではこれ以外では小さいVLTのUVES, GTCのMEGARAでHH514のスペクトル観測スペクトル観測結果の例Velocity (Km s¯上下がスリットの南北の広がり左右が波長（速度）下の南側からcut1, 2, 3に分割Cut 1には円盤成分とjet base Cut 2にはknot Cut 3にはNebula成分のみPyNebで電子密度、温度の解析Jet base: 2.3x105 /cc Knot: 7x104 /cc非常に高密度温度は光電離平衡で期待される9000Kと整合的Abundance in logarithmic unit with n (H) = 12.
S, Fe, NiでNebulaの値よりも大いそれ以外は同程度
Sのoverabundanceについて
Nebulaや円盤風ではみられないFeやNiについても、Nebulaや円盤では少なく、HH中で多くなってい。 FeやNiが多いのはHH中でのダストの破壊で説明できる。 Sについてもダストの破壊が関係か。中性でも電離している場合でも、FeやNiが多いHHはよくみられる。ダストの破壊はHHのshockかjetの根本で起こるか。これほどSが過剰なHHは初めて観測された。 Kama et al. (2019)によると、円盤での惑星形成過程でSが貯められる→そのダストをjetに供給できれば説明ができるかもしれない
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Magnetic fields and outflows in the large Bok globule CB 54
ABSTRACT
We have observed the large Bok globule CB 54 in 850 μm polarised light using the POL-2 polarimeter on the James Clerk Maxwell Telescope (JCMT). We find that the magnetic field in the periphery of the globule shows significant, ordered deviation from the mean field direction in the globule centre. This deviation appears to correspond with the extended but relatively weak 12CO outflow emanating from the Class 0 sources at t the centre of the globule. Energetics analysis suggests that if the outflow is reshaping the magnetic field in the globule’s periphery, then we can place an upper limit of < 27 μ G on the magnetic field strength in the globule’s periphery. Comparison with archival Planck and CARMA measurements shows that the field in the centre of the globule is consistent over several orders of magnitude in size scale, and oriented parallel to the density structure in the region in projection. We thus hypothesise that while non-thermal motions in the region may be sub-Alfvénic, the magnetic field is subdominant to gravity over a wide range of size scales. Our results suggest that even a relatively weak outflow may be able to significantly reshape magnetic fields in star-forming regions on scales > 0.1 pc.観測対象：ボックグロビュールCB54 JCMTのPOL-2を使って850umの偏光観測ボックグロビュール典型的に~0.1pc,数十Msun ->低質量星形成CB54には5つのpoint source CB54YC1-I, II, MIR-a, b, cここでは星形成で重要となる磁場形状とアウトフローについて注目する偏光ベクトル磁場の向き黒線はPlanckで得られた磁場の向きCB 54の中心付近の磁場の向きはlarge scaleの向きと揃う。外側ではズレる。外側の磁場は12COのアウトフローの向きと揃っているように見える。物理量の導出フラックスから質量~ 117Msun平均密度5x103 cc-1先行研究と整合的16 arcsecを境界に内側と外側に分ける外側  ～ 64 Msun,  3x103 cc-1内側　~53Msun外側領域の磁場がアウトフローで曲げられた場合(磁場エネルギー)<(運動エネルギー)としてB<27 uG CARMAとの比較緑線がCARMAの磁場の向き灰色がPOL-2高密度領域では揃っているMIR-cの高速アウトフローの方向では、外側領域の磁場の向きと揃う。広いスケールにわたって磁場の向きが整合的→乱流はsub-Alfvenicアウトフローによっては向きが大きく曲げられる。
36
The disk of FU Orionis viewed with MATISSE/VLTI: first interferometric observations
in L and M bands
Aims. We studied the accretion disk of the archetypal eruptive young star FU Orionis with the use of mid-infrared interferometry, which enabled us to resolve the innermost regions of the disk down to a spatial resolution of 3 milliarcseconds (mas) in the L band, that is, within 1 au of the protostar. Methods. We used the interferometric instrument MATISSE/VLTI to obtain observations of FU Ori’s disk in the L, M, and N bands with multiple baseline configurations. We also obtained contemporaneous photometry in the optical (UBVRIP'? ; SAAO and Konkoly Observatory) and near-infrared (JHK , ; NOT). Our results were compared with radiative transfer simulations modeled by radmc-3d. Results. The disk of FU Orionis is marginally resolved with MATISSE, suggesting that the region emitting in the thermal infrared is rather compact. An upper limit of ～ 1.3 ± 0.1 mas (in L) can be given for the diameter of the disk region probed in the L band, corresponding to 0.5 au at the adopted Gaia EDR3 distance. This represents the hot, gaseous region of the accretion disk. The N-band data indicate that the dusty passive disk is silicate-rich. Only the innermost region of said dusty disk is found to emit strongly in the N band, and it is resolved at an angular size of ~ 5 mas, which translates to a diameter of about 2 au. The observations therefore place stringent constraints for the outer radius of the inner accretion disk. Dust radiative transfer simulations with radmc-3p provide adequate fits to the spectral energy distribution from the optical to the submillimeter and to the interferometric observables when opting for an accretion rate M ～ 2 × 10 -5 M 。yr-1 and assuming M 。= 0.6 M 。Most importantly, the hot inner accretion disk’s outer radius can be fixed at 0.3 au. The outer radius of the dusty disk is placed at 100 au, based on constraints from scattered-light images in the literature. The dust mass contained in the disk is 2.4 × 10~4 M o, and for a typical gas-to-dust ratio of 100, the total mass in the disk is approximately 0.02 M . We did not find any evidence for a nearby companion in the current interferometric data, and we tentatively explored the case of disk misalignment. For the latter, our modeling results suggest that the disk orientation is s imilar to that found in previous imaging studies by ALMA. Should there be an asymmetry in the very compact, inner accretion disk, this might be resolved at even smaller spatial scales (≤ 1 mas).
38
NIR spectroscopic survey of protostellar jets in the star forming region IC 1396N
Context. The bright-rimmed cloud IC 1396N, associated with an intermediate-mass star-forming region, hosts a number of CO, molecular hydrogen and Herbig-Haro (HHs) outflows powered by a set of millimetre compact sources. Aims. The aim of this work is to characterise the kinematics and physical conditions of the H 2 emission features spread over the IC 1396N region, which appear as chains of knots with a jet-like morphology, tracing different H 2 outflows, and to obtain further information about (and an identification of) the driving sources. Methods. Low-resolution, long-slit near-infrared spectra were acquired with the NICS camera at the TNG telescope, using grisms KB (R ~ 1200), HK and JH (R ~ 500). Several slit pointings and PA were used throughout the IC 1396N region in order to sample a number of the H 2 knots previously detected in deep H 2 2.12 μm images. Results. The knots exhibit rich ro-vibrational spectra of H 2 , consistent with shock-excited excitation, from which radial velocities and relevant physical conditions of the IC 1396N H 2 outflows were derived. These also allowed estimating extinction ranges towards several features. [Fe π] emission was only detected towards a few knots, which also display unusually large H 2 1–0 S(3)/S(1) flux ratios. The obtained radial velocities confirm that most of the outflows are close to the plane of the sky. Nearby knots in the same chain often display different radial velocities, both blue-shifted and red-shifted, which we interpret as due to ubiquitous jet precession in the driving sources or the development of oblique shocks. One of the chains (strand A, i. e. knots A1 to A15) appears as a set of features trailing a leading bow-shock structure consistent with the results of 3-D magneto-hydrodynamical models. Either side of the leading bow-shock (A15) exhibits a different radial velocity, whose possible explanations are discussed in the paper. Our data cannot confirm whether strands A and B have both been originated by the intermediate mass young stellar object [BGE2002] BIMA 2, as a simple model of precessing jet cannot account for their locations. Conclusions. NIR spectroscopy has confirmed that most of the H 2 ro-vibrational emission in IC 1396N is shock-excited rather than uv-excited in photon-dominated regions. It has evidenced a complex kinematical structure in most strands of emitting knots, as well.
39

The Structure, Excitation, and Dynamics of the Inner Galactic InterStellar Medium (SEDIGISM) survey has produced high (spatial and spectral) resolution 13CO (2–1) maps of the Milky Way. It has allowed us to investigate the molecular interstellar medium in the inner Galaxy at an unprecedented level of detail and characterise it into molecular clouds. In a previous paper, we have classified the SEDIGISM clouds into four morphologies. However, how the properties of the clouds vary for these four morphologies is not well understood. Here, we use the morphological classification of SEDIGISM clouds to find connections between the cloud morphologies, their integrated properties, and their location on scaling relation diagrams. We observe that ring-like clouds show the most peculiar properties, having, on average, higher masses, sizes, aspect ratios and velocity dispersions compared to other morphologies. We speculate that this is related to the physical mechanisms that regulate their formation and evolution, for example, turbulence from stellar feedback can often results in the creation of bubble-like structures. We also see a trend of morphology with virial parameter whereby ring-like, elongated, clumpy and concentrated clouds have virial parameters in a decreasing order. Our findings provide a foundation for a better understanding of the molecular cloud behaviour based on their measurable properties.
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An Interferometric View of H-MM1. I. Direct Observation of NH3 Depletion
Spectral lines of ammonia, NH 3 , are useful probes of the physical conditions in dense molecular cloud cores. In addition to advantages in spectroscopy, ammonia has also been suggested to be resistant to freezing onto grain surfaces, which should make it a superior tool for studying the interior parts of cold, dense cores. Here we present high-resolution NH3 observations with the Very Large Array (VLA) and Green Bank Telescope (GBT) towards a prestellar core. These observations show an outer region with a fractional NH3 abundance of X(NH3) = (1.975 ± 0.005) × 10−8 (±10% systematic), but it also reveals that after all, the X (NH 3 ) starts to decrease above a H 3 column density of ≈ 2.6 × 10 22 cm −2, We derive a density model for the core and find that the break-point in the fractional abundance occurs at t the density n(H 2 ) ～ 2 × 10 cm−3, and beyond this point the fractional abundance decreases with increasing density, following the power law n-1.1. This power-law behavior is well reproduced by chemical models where adsorption onto grains dominates the removal of ammonia and related species from the gas at high densities.) We suggest that the break-point density changes from core to core depending on the temperature and the grain properties, but that the depletion power law is anyway likely to be close to n-1 owing to the dominance of accretion in the central parts of starless cores. 41
From Bubbles and Filaments to Cores and Disks: Gas Gathering and Growth of Struc-
ture Leading to the Formation of Stellar Systems
Abstract  The study of the development of structures on multiple scales in the cold interstellar medium has experienced rapid expansion in the past decade, on both the observational and the theoretical front.  Spectral line studies at (sub-)millimeter wavelengths over a wide range of physical scales have provided unique probes of the kinematics of dense gas in star-forming regions, and have been complemented by extensive, high dynamic range dust continuum surveys of the column density structure of molecular cloud complexes, while dust polarization maps have highlighted the role of magnetic fields. This has been accompanied by increasingly sophisticated numerical simulations including new physics (e.g., supernova driving, cosmic rays, non-ideal magneto-hydrodynamics, radiation pressure) and new techniques such as zoom-in simulations allowing multi-scale studies.  Taken together, these new data have emphasized the anisotropic growth of dense structures on all scales, from giant ISM bubbles driven by stellar feedback on ～50–100 pc scales through parsec-scale molecular filaments down to < 0.1 pc dense cores and <  1000 au protostellar disks. Combining observations and theory, we present a coherent picture for the formation and evolution of these structures and synthesize a comprehensive physical scenario for the initial conditions and early stages of star and disk formation.