An SiO Toroid and Wide-angle Outflow associated with the Massive Protostar W75N(B)-VLA2
Jose F. Gomez, Jose M. Torrelles, Josep M. Girart, Gabriele Surcis, Jeong-Sook Kim, Jorge Canto, Guillem Anglada, Salvador Curiel, Wouter H. T. Vlemmings, Carlo… 展开作者
Jose F. Gomez, Jose M. Torrelles, Josep M. Girart, Gabriele Surcis, Jeong-Sook Kim, Jorge Canto, Guillem Anglada, Salvador Curiel, Wouter H. T. Vlemmings, Carlos Carrasco-Gonzalez, Adriana R. Rodriguez-Kamenetzky, Soon-Wook Kim, Ciriaco Goddi, Huib J. van Langevelde, Alvaro Sanchez-Monge
备注：
To be published in The Astrophysical Journal Letters. Sixteen pages, seven figures. Updated metadata
We have carried out ALMA observations of the massive star-forming region W75N(B), which contains the massive protostars VLA1, VLA2, and VLA3. Particularly, VLA2 is an enigmatic protostar associated with a wind-driven H$_2$O maser shell, which has evolved from an almost isotropic outflow to a collimated one in just 20 years. The shell expansion seemed to be halted by an obstacle located to the northeast of VLA2. Here we present our findings from observing the 1.3 mm continuum and H$_2$CO and SiO emission lines. Within a region of $\sim 30"$ ($\sim 39,000$ au) diameter, we have detected 40 compact mm-continuum sources, three of them coinciding with VLA1, VLA2, and VLA3. While the H$_2$CO emission is mainly distributed in a fragmented structure around the three massive protostars, but without any of the main H$_2$CO clumps spatially coinciding with them, the SiO is highly concentrated on VLA2, indicating the presence of very strong shocks generated near this protostar. The SiO emission is clearly resolved into an elongated structure ($\sim 0.6"\times0.3"$; $\sim 780$ au$\times$390 au) perpendicular to the major axis of the wind-driven maser shell. The structure and kinematics of the SiO emission are consistent with a toroid and a wide-angle outflow surrounding a central mass of $\sim 10$ M$_{\odot}$, thus supporting previous theoretical predictions regarding the evolution of the outflow. Additionally, we have identified the expected location and estimated the gas density of the obstacle that is hindering the expansion of the maser shell.
To study the early phases of massive star formation, we present ALMA observations of SiO(5-4) emission and VLA observations of 6 cm continuum emission towards 32 Infrared Dark Cloud (IRDC) clumps, spatially resolved down to $\lesssim 0.05$ pc. Out of the 32 clumps, we detect SiO emission in 20 clumps, and in 11 of them the SiO emission is relatively strong and likely tracing protostellar outflows. Some SiO outflows are collimated, while others are less ordered. For the six strongest SiO outflows, we estimate basic outflow properties. In our entire sample, where there is SiO emission, we find 1…
Context. The relationship between outflow launching and formation of accretion disks around young stellar objects is still not entirely understood, which is why spectrally and spatially resolved observations are needed. Recently, the Atacama Large Millimetre/sub-millimetre Array (ALMA) has carried out long-baseline observations towards a handful of sources, revealing connections between outflows and the inner regions of disks. Aims. Here we aim to determine the small-scale kinematic and morphological properties of the outflow from the isolated protostar B335 for which no Keplerian disk has, so…
As a part of the CALYPSO large programme, we constrain the properties of protostellar jets and outflows in a sample of 21 Class 0 protostars with internal luminosities, Lint, from 0.035 to 47 Lsun. We analyse high angular resolution (~0.5"-1") IRAM PdBI observations in CO (2-1), SO ($5_6-4_5$), and SiO (5-4). CO (2-1), which probes outflowing gas, is detected in all the sources (for the first time in SerpS-MM22 and SerpS-MM18b). Collimated high-velocity jets in SiO (5-4) are detected in 67% of the sources (for the first time in IRAS4B2, IRAS4B1, L1448-NB, SerpS-MM18a), and 77% of these also sh…
We present high-sensitivity 2'x4' maps of the J=2-1 rotational lines of SiO, CO, 13CO and C18O, observed toward the filamentary Infrared Dark Cloud (IRDC) G035.39-00.33. Single-pointing spectra of the SiO J=2-1 and J=3-2 lines toward several regions in the filament, are also reported. The SiO images reveal that SiO is widespread along the IRDC (size >2 pc), showing two different components: one bright and compact arising from three condensations (N, E and S), and the other weak and extended along the filament. While the first component shows broad lines (linewidths of ~4-7 kms-1) in both SiO J…
In this paper we present Combined Array for Research in Millimeter-wave Astronomy (CARMA) 3.5 mm observations and SubMillimeter Array (SMA) 870 microns observations toward the high-mass star-forming region IRAS 1816-2048, the core of the HH 80/81/80N system. Molecular emission from HCN, HCO+ and SiO is tracing two molecular outflows (the so-called Northeast and Northwest outflows). These outflows have their origin in a region close to the position of MM2, a millimeter source known to harbor a couple protostars. We estimate for the first time the physical characteristics of these molecular outf…
Jets and outflows trace the accretion history of protostars. High-velocity molecular jets have been observed from several protostars in the early Class\,0 phase of star formation, detected with the high-density tracer SiO. Until now, no clear jet has been detected with SiO emission from isolated evolved Class\,I protostellar systems. We report a prominent dense SiO jet from a Class\,I source G205S3 (HOPS\,315: T$_{bol}$ $\sim$ 180 K, spectral index $\sim$ 0.417), with a moderately high mass-loss rate ($\sim$ 0.59 $\times$ 10$^{-6}$ M$_\odot$ yr$^{-1}$) estimated from CO emission. Together, the…
The study of the early phases of star and planet formation is important to understand the physical and chemical history of stellar systems such as our own. In particular, protostars born in rich clusters are prototypes of the young Solar System. In the framework of the Seeds Of Life In Space (SOLIS) large observational project, the aim of the present work is to investigate the origin of the previously inferred high flux of energetic particles in the protocluster FIR4 of the Orion Molecular Cloud 2 (OMC-2), which appears asymmetric within the protocluster itself. Interferometric observations ca…
We have analyzed the OCS, H$_2$CS, CH$_3$OH, and HCOOCH$_3$ data observed toward the low-mass protostar IRAS 16293--2422 Source B at a sub-arcsecond resolution with ALMA. A clear chemical differentiation is seen in their distributions; OCS and H$_2$CS are extended with a slight rotation signature, while CH$_3$OH and HCOOCH$_3$ are concentrated near the protostar. Such a chemical change in the vicinity of the protostar is similar to the companion (Source A) case. The extended component is interpreted by the infalling-rotating envelope model with a nearly face-on configuration. The radius of the…
We have used deep near-infrared observations with adaptive optics to discover a distributed population of low-mass protostars within the filamentary Infrared Dark Cloud G34.43+00.24. We use maps of dust emission at multiple wavelengths to determine the column density structure of the cloud. In combination with an empirically-verified model of the magnitude distribution of background stars, this column density map allows us to reliably determine overdensities of red sources that are due to embedded protostars in the cloud. We also identify protostars through their extended emission in K-band wh…
We present the first resolved observations of the 1.3mm polarized emission from the disk-like structure surrounding the high-mass protostar Cepheus A HW2. These CARMA data partially resolve the dust polarization, suggesting an uniform morphology of polarization vectors with an average position angle of 57 degrees and an average polarization fraction of 2.0%. The distribution of the polarization vectors can be attributed to (1) the direct emission of magnetically aligned grains of dust by a uniform magnetic field, or (2) the pattern produced by the scattering of an inclined disk. We show that b…
We report new VLA and e-MERLIN high resolution and sensitivity images of the Triple Radio continuum Source in the Serpens star forming region. These observations allowed us to perform a deep multi-frequency, multi-epoch study by exploring the innermost regions (<~100 au) of an intermediate-mass YSO for the first time, with a physical resolution of ~15 au. The kinematic analysis of knots recently ejected by the protostar indicates that the jet is undergoing episodic variations in velocity. In addition, our multi-frequency images reveal striking characteristics, e.g., a highly collimated ionized…
HH 211 is a highly collimated jet with a chain of knots and a wiggle structure on both sides of a young Class 0 protostar. We used two epochs of Atacama Large Millimeter/submillimeter Array (ALMA) data to study its inner jet in the CO(J=3-2), SiO(J=8-7), and SO(N_J=8_9-7_8) lines at $\sim$25 AU resolution. With these ALMA and previous 2008 Submillimeter Array (SMA) data, the proper motion of 8 knots within $\sim$250 AU of the central source is found to be $\sim$0.068" per year ($\sim$102 km/s), consistent with previous measurements in the outer jet. At $\sim$4 times higher resolution, the refl…
We report new Atacama Large Millimeter/Submillimeter Array (ALMA) observations of a circumstellar disk around Source I in Orion KL, an archetype of massive protostar candidate. We detected two ortho-H$_{2}$O lines at 321 GHz ($10_{2,9}$-$9_{3,6}$) and 336 GHz ($ν_{2}=1, 5_{2,3}$-$6_{1,6}$) for the first time in Source I. The latter one is in vibrationally excited state at the lower state energy of 2939 K, suggesting an evidence of hot molecular gas close to Source I. The integrated intensity map of the 321 GHz line is elongated along the bipolar outflow while the 336 GHz line map is unresolved…
Dust Seeding Molecules in a Massive Protostar -- Detection of TiO in Orion Source I
RIKEN Pioneering Research Institute（理化学研究所先锋研究本部）；The Graduate University for Advanced Studies, SOKENDAI（日本综合研究院 (SOKENDAI)）；University of Florida（佛罗里达大学）；Massachusetts Institute of Technology（麻省理工学院）；Kyoto University（京都大学）；The University of Tokyo（东京大学）；Institute of Science Tokyo（东京科学大学）；Shanghai Jiao Tong University（上海交通大学）；National Astronomical Observatory of Japan（日本国立天文台）
The current paradigm of star formation through accretion disks, and magnetohydrodynamically driven gas ejections, predicts the development of collimated outflows, rather than expansion without any preferential direction. We present radio continuum observations of the massive protostar W75N(B)-VLA 2, showing that it is a thermal, collimated ionized wind and that it has evolved in 18 years from a compact source into an elongated one. This is consistent with the evolution of the associated expanding water-vapor maser shell, which changed from a nearly circular morphology, tracing an almost isotro…
Fast jets are thought to be a crucial ingredient of star formation because they might extract angular momentum from the disk and thus allow mass accretion onto the star. However, it is unclear whether jets are ubiquitous, and likewise, their contribution to mass and angular momentum extraction during protostar formation remains an open question. Our aim is to investigate the ejection process in the low-mass Class 0 protostar L1157. This source is associated with a spectacular bipolar outflow, and the recent detection of high-velocity SiO suggests the occurrence of a jet. Observations of CO 2-1…
We observed polarization of the SiO rotational transitions from Orion Source I (SrcI) to probe the magnetic field in bipolar outflows from this high mass protostar. Both 43 GHz $J$=1-0 and 86 GHz $J$=2-1 lines were mapped with $\sim$20 AU resolution, using the Very Large Array (VLA) and Atacama Large Millimeter/Submillimeter Array (ALMA), respectively. The $^{28}$SiO transitions in the ground vibrational state are a mixture of thermal and maser emission. Comparison of the polarization position angles in the $J$=1-0 and $J$=2-1 transitions allows us to set an upper limit on possible Faraday rot…
We have observed the Class I protostellar source Elias 29 with Atacama Large Millimeter/submillimeter Array (ALMA). We have detected CS, SO, $^{34}$SO, SO$_2$, and SiO line emissions in a compact component concentrated near the protostar and a ridge component separated from the protostar by 4\arcsec\ ($\sim 500$ au). The former component is found to be abundant in SO and SO$_2$ but deficient in CS. The abundance ratio SO/CS is as high as $3^{+13}_{-2} \times 10^2$ at the protostar, which is even higher than that in the outflow-shocked region of L1157 B1. However, organic molecules (HCOOCH$_3$,…
The canonical theory of star formation in a magnetized environment predicts the formation of hourglass-shaped magnetic fields during the prestellar collapse phase. In protostellar cores, recent observations reveal complex and strongly distorted magnetic fields in the inner regions that are sculpted by rotation and outflows. We conduct resistive, nonideal magnetohydrodynamic (MHD) simulations of a protostellar core and employ the radiative transfer code POLARIS to produce synthetic polarization segment maps. Comparison of our mock-polarization maps based on the toroidal-dominated magnetic field…
We have observed the very low-mass Class 0 protostar IRAS 15398-3359 at scales ranging from 50 au to 1800 au, as part of the ALMA Large Program FAUST. We uncover a linear feature, visible in H2CO, SO, and C18O line emission, which extends from the source along a direction almost perpendicular to the known active outflow. Molecular line emission from H2CO, SO, SiO, and CH3OH further reveals an arc-like structure connected to the outer end of the linear feature and separated from the protostar, IRAS 15398-3359, by 1200 au. The arc-like structure is blue-shifted with respect to the systemic veloc…
The youngest low-mass protostars are known to be chemically rich, accreting matter most vigorously, and producing the most powerful outflows. Molecules are unique tracers of these phenomena. We use ALMA to study several outflow sources in the Serpens Main region. The most luminous source, Ser-SMM1, shows the richest chemical composition, but some complex molecules are also present in S68N. No emission from complex organics is detected toward Ser-emb 8N, which is the least luminous in the sample. We discuss whether these differences reflect an evolutionary effect or whether they are due to diff…
We have observed a cluster forming clump (MM3) associated with the infrared dark cloud G34.43+00.24 in the 1.3 mm continuum and the CH3OH, CS, 13CS, SiO, CH3CH2CN, and HCOOCH3 lines with the Atacama Large Millimeter/submillimeter Array and in K-band with the Keck telescope. We have found a young outflow toward the center of this clump in the SiO, CS, and CH3OH lines. This outflow is likely driven by a protostar embedded in a hot core, which is traced by the CH3CH2CN, HCOOCH3, 13CS, and high excitation CH3OH lines. The size of the hot core is about 800 x 300 AU in spite of its low mass (<1.1 M_…
We present 0.25 arcsec resolution (35 au) ALMA 1.3 mm dust polarization observations for 37 young stellar objects (YSOs) in the Ophiuchus cloud. These data encompass all the embedded protostars in the cloud and several Flat and Class II objects to produce the largest, homogeneous study of dust polarization on disk scales to date. The goal of this study is to study dust polarization down to disk scales. We find that 14/37 (38%) of the YSOs are detected in polarization. Nine of these sources have uniform polarization angles and four sources have azimuthal polarization. The sources with uniform p…
The accretion history of protostars remains widely mysterious even though it represents one of the best ways to understand the protostellar collapse that leads to the formation of stars. Molecular outflows are here used to characterize the protostellar accretion phase in W43-MM1. The W43-MM1 protocluster host a sufficient number of protostars to statistically investigate molecular outflows in a single, homogeneous region. We used the CO(2-1) and SiO(5-4) line datacubes, taken as part of an ALMA mosaic with a 2000 AU resolution, to search for protostellar outflows, evaluate the influence that t…
The fastest molecular component to the protostellar outflows -- extremely high-velocity (EHV) molecular jets -- are still puzzling since they are seen only rarely. The first aim is to analyze the interaction between the EHV jet and the slow outflow by comparing their outflow force content. The second aim is to analyze the chemical composition of the different outflow velocity components and to reveal the spatial location of molecules. ALMA 3 mm and 1.3 mm observations of five outflow sources at 130 -- 260 au resolution in the Serpens Main cloud are presented. Observations of CO, SiO, H$_2$CO a…
Early Planet Formation in Embedded Disks (eDisk). VII. Keplerian Disk, Disk Substructure, and Accretion Streamers in the Class 0 Protostar IRAS 16544-1604 in CB 68
基于 ALMA eDisk 项目对 CB 68 中 0 类原恒星 IRAS 16544-1604 的观测，研究揭示了其具有耀展和非轴对称结构的 ~30 au 开普勒旋转盘，并发现了连接盘面的 ~1500 au 吸积流及伴随的吸积激波与外流。
We present ALMA archival data for 219-235 GHz continuum and line observations toward the hot molecular core (HMC) W49N MCN-a (UCHII region J1) at a resolution of ~0."3. The dust continuum emission, showing an elongated structure of 1."40x0."95 (PA=43.5deg) perpendicular to the outflow seen in SiO and SO, represents a rotating flattened envelope, or torus, with a radius of 7,800au inclined at 47.5deg or larger. The emissions from CH3CN and 11 molecular lines exhibit a consistent velocity gradient as a result of rotation. The magnitude of each velocity gradient is different, reflecting that each…
$Aims.$ We study the relation between the jet and the outflow in the IRAS 04166+2706 protostar. This Taurus protostar drives a molecular jet that contains multiple emission peaks symmetrically located from the central source. The protostar also drives a wide-angle outflow consisting of two conical shells. $Methods.$ We have used the Atacama Large Millimeter/submillimeter Array (ALMA) interferometer to observe two fields along the IRAS 04166+2706 jet. The fields were centered on a pair of emission peaks that correspond to the same ejection event, and were observed in CO(2-1), SiO(5-4), and SO(6…
We present an observational study of the vibrationally excited H$_{2}$O line at 658 GHz ($ν_{2}$=1, 1$_{1, 0}$-1$_{0, 1}$) toward Orion KL using the Atacama Large Millimeter/Submillimeter Array (ALMA). This line is clearly detected at the position of the massive protostar candidate, the Source I. The spatial structure is compact with a size of about 100 AU and is elongated along the northeast-southwest low-velocity (18 km s$^{-1}$) bipolar outflow traced by 22 GHz H$_{2}$O masers, SiO masers, and thermal SiO lines. A velocity gradient can be seen perpendicular to the bipolar outflow. Overall s…
Context: Jets and outflows are key ingredients in the formation of stars across the mass spectrum. In clustered regions, understanding powering sources and outflow components poses a significant problem. Aims: To understand the dynamics in the outflow(s) from a cluster in the process of forming massive stars. Methods: We use new VLA observations of the molecular gas (SiO, CS, OCS and \molec) in the massive star forming region IRAS 17233-3606 which contains a number of HII regions. We compare these observations to previously published molecular data for this source in order to get a holistic vi…
Sensitive and high angular resolution ($\sim$ 0.4\arcsec) SO$_2$[22$_{2,20}$ $\to$ 22$_{1,21}$] and SiO[5$\to$4] line and 1.3 and 7 mm continuum observations made with the Submillimeter Array (SMA) and the Very Large Array (VLA) towards the young massive cluster W51 IRS2 are presented. We report the presence of a large (of about 3000 AU) and massive (40 M$_\odot$) dusty circumstellar disk and a hot gas molecular ring around a high-mass protostar or a compact small stellar system associated with W51 North. The simultaneous observations of the silicon monoxide molecule, an outflow gas tracer, fu…
Numerical simulations of outflows formed during the collapse of 100 M_sun cloud cores are presented. We derive a generalised criterion from MHD wind theory to analyse the launching mechanism of these outflows. The criterion is successfully applied to the whole outflow structure and cases with sub-Keplerian disc rotation. It allows us to decide whether an outflow is driven centrifugally or by the toroidal magnetic pressure. We show that quantities such as the magnetic field line inclination or the ratio of the toroidal to poloidal magnetic field alone are insufficient to determine the driving m…
(Abridged) Mid- and far-infrared observations of the environment around embedded protostars reveal a plethora of high excitation molecular and atomic emission lines. In this work we present spectro-imaging observations of the HH211 system with Herschel/PACS that record emission from major molecular (CO, H2O and OH) and atomic coolants (e.g. [OI]). Molecular lines are mainly exited at the terminal bowshocks of the outflow and around the position of the protostar. All lines show maxima at the southeast bowshock with the exception of water emission that peaks around the central source. Excitation…
Sufficiently massive clumps of molecular gas collapse under self-gravity and fragment to spawn a cluster of stars that have a range of masses. We investigate observationally the early stages of formation of a stellar cluster in a massive filamentary infrared dark cloud, G28.34+0.06 P1, in the 1.3mm continuum and spectral line emission using the ALMA. Sensitive continuum data reveal further fragmentation in five dusty cores at a resolution of several 10^3 AU. Spectral line emission from C18O, CH3OH, 13CS, H2CO and N2D+ are detected for the first time toward these dense cores. We found that thre…
Planck Galactic Cold Clumps (PGCCs) are contemplated to be the ideal targets to probe the early phases of star formation. We have conducted a survey of 72 young dense cores inside PGCCs in the Orion complex with the Atacama Large Millimeter/submillimeter Array (ALMA) at 1.3\,mm (band 6) using three different configurations (resolutions $\sim$ 0$\farcs$35, 1$\farcs$0, and 7$\farcs$0) to statistically investigate their evolutionary stages and sub-structures. We have obtained images of the 1.3\,mm continuum and molecular line emission ($^{12}$CO, and SiO) at an angular resolution of $\sim$ 0$\far…
The importance of the physical environment in the evolution of newly formed low-mass stars remains an open question. In particular, radiation from nearby more massive stars may affect both the physical and chemical structure of these kinds of young stars. Aims: To constrain the physical characteristics of a group of embedded low-mass protostars in Corona Australis in the vicinity of the young luminous Herbig Be star R CrA. Methods: Millimetre wavelength maps of molecular line and continuum emission towards the low-mass star forming region IRS7 near R CrA from the SMA and APEX are presented. Th…
JOYS$+$: A JWST/MIRI survey of the evolution of H$_2$ winds and jets from low-mass protostars
Leiden University（莱顿大学）；Max-Planck-Institut für Extraterrestrische Physik（马克斯·普朗克地外物理学研究所）；INAF-Osservatorio Astronomico di Capodimonte（意大利国家天体物理研究所卡波迪蒙特天文台）；Institut de Ciències de l’Espai (ICE-CSIC)（空间科学研究所（加泰罗尼亚高等研究委员会））；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚空间研究所）；Max Planck Institute for Astronomy（马克斯·普朗克天文学研究所）；University of Helsinki（赫尔辛基大学）；Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）；European Southern Observatory（欧洲南方天文台）
Using the Atacama Large Millimeter/submillimeter Array (ALMA), we investigated a peculiar millimeter source MMS 3 located in the Orion Molecular Cloud 3 (OMC-3) region in the 1.3 mm continuum, CO ($J$=2-1), SiO ($J$=5-4), C$^{18}$O ($J$=2-1), N$_2$D$^+$ ($J$=3-2), and DCN ($J$=3-2) emissions. With the ALMA high angular resolution ($\sim$0''.2), we detected a very compact and highly centrally condensed continuum emission with a size of 0''.45 $\times$ 0''.32 (P.A.=0.22$^\circ$). The peak position coincides with the locations of previously reported $Spitzer$/IRAC and X-ray sources within their p…
We study mass accretion and ejection in the vicinity of massive star forming cores using high-resolution (5 au) 3D AMR numerical simulations. We investigate the mechanisms at the origin of outflows and characterise the properties of the disc forming around massive protostars. We include both protostellar radiative feedback via PMS evolutionary tracks and magnetic ambipolar diffusion. We studied 3 different cases: purely hydrodynamical, ideal MHD, and ambipolar diffusion. In the resistive models, we investigate the effects the initial amplitude of both magnetic field and rotation have on the pr…
The filament IRDC G035.39--00.33 in the W48 molecular complex is one of the darkest infrared clouds observed by \textit{Spitzer}. It has been observed by the PACS (70 and 160\,$\micron$) and SPIRE (250, 350, and 500\,$\micron$) cameras of the \textit{Herschel} Space Observatory as part of the W48 molecular cloud complex in the framework of the HOBYS key programme. The observations reveal a sample of 28 compact sources (deconvolved FWHM sizes $<$0.3 pc) complete down to $\sim$$5 \msun$ in G035.39--00.33 and its surroundings. Among them, 13 compact sources are massive dense cores with masses $>$…
Early Planet Formation in Embedded Disks (eDisk) III: A first high-resolution view of sub-mm continuum and molecular line emission toward the Class 0 protostar L1527 IRS
We present ALMA Cycle 1 observations of the HH46/47 molecular outflow using combined 12m array and ACA observations. The improved angular resolution and sensitivity of our multi-line maps reveal structures that help us study the entrainment process in much more detail and allow us to obtain more precise estimates of outflow properties than previous observations. We use 13CO(1-0) and C18O(1-0) emission to correct for the 12CO(1-0) optical depth to accurately estimate the outflow mass, momentum and kinetic energy. This correction increases the estimates of the mass, momentum and kinetic energy b…
