Archival optical spectra from the Sloan Digital Sky Survey of two optically faint flat spectrum protostars, IRAS 04369+2539 and IRAS 05451+0037, show strong emission-line features including -- notably -- clear and broad emission across several molecular bands of TiO and VO. The molecular emission is indicative of dense, warm circumstellar gas and has been seen previously in only one object: the flat spectrum protostar IRAS 20496+4354 during a strong optical outburst (PTF 10nvg; Covey et al. 2011). The presence of broad molecular emission features in two additional objects having similar mid-infrared properties (but not known to be undergoing outbursts) could provide new insight into phases of rapid accretion / outflow at early stages of the protoplanetary disk. At present, the relevant geometry and the formation or heating mechanisms responsible for the observed TiO / VO cooling emission remain unexplained.
(Abridged) The water deuterium fractionation (HDO/H$_2$O abundance ratio) has traditionally been used to infer the amount of water brought to Earth by comets. Measuring this ratio in deeply-embedded low-mass protostars makes it possible to probe the critical stage when water is transported from clouds to disks in which icy bodies are formed. We present sub-arcsecond resolution observations of HDO in combination with H$_2^{18}$O from the PdBI toward the three low-mass protostars NGC 1333-IRAS 2A, IRAS 4A-NW, and IRAS 4B. The resulting HDO/H$_2$O ratio is $7.4\pm2.1\times10^{-4}$ for IRAS 2A, $1…
Sub-arcsecond ($0.^{\prime\prime}5$) images of H$_2$CO and CCH line emission have been obtained in the $0.8$ mm band toward the low-mass protostar IRAS 15398-3359 in the Lupus 1 cloud as one of the Cycle 0 projects of the Atacama Large Millimeter/Submillimeter Array. We have detected a compact component concentrated in the vicinity of the protostar and a well-collimated outflow cavity extending along the northeast-southwest axis. The inclination angle of the outflow is found to be about $20^\circ$, or almost edge-on, based on the kinematic structure of the outflow cavity. This is in contrast t…
Outbursts of young stellar objects occur when the mass accretion rate suddenly increases. However, such outbursts are difficult to detect for deeply embedded protostars due to their thick envelope and the rarity of outbursts. The near-IR spectroscopy is a useful tool to identify ongoing outburst candidates by the characteristic absorption features that indicate a disk origin. However, without high-resolution spectroscopy, the spectra of outburst candidates can be confused with the late-type stars since they have similar spectral features. For the protostar IRAS 16316-1540, the near-IR spectrum…
We are conducting a Jansky VLA Ka-band (8 mm and 1 cm) and C-band (4 cm and 6.4 cm) survey of all known protostars in the Perseus Molecular Cloud, providing resolution down to $\sim$0.06'' and $\sim$0.35" in Ka-band and C-band, respectively. Here we present first results from this survey that enable us to examine the source NGC 1333 IRAS2A in unprecedented detail and resolve it into a proto-binary system separated by 0.621"$\pm$0.006" ($\sim$143 AU) at 8 mm, 1 cm, and 4 cm. These 2 sources (IRAS2A VLA1 and VLA2) are likely driving the two orthogonal outflows known to originate from IRAS2A. The…
The millimeter-wave rotational transition line ($J_K = 1_0 - 0_0$) of deuterated methane CH$_3$D has tentatively been detected toward the low-mass Class 0 protostar IRAS 04368+2557 in L1527 with the Heinrich Hertz Submillimeter Telescope. This is the first detection of CH$_3$D in interstellar clouds, if confirmed. The column density and fractional abundance of CH$_3$D are determined to be $(9.1\pm3.4) \times 10^{15}$ cm$^{-2}$ and $(3.0\pm1.1) \times 10^{-7}$, respectively, where we assume the rotational temperature of 25 K. The column density and fractional abundance of the gaseous CH$_4$ are…
Magnetic fields can regulate disk formation, accretion and jet launching. Until recently, it has been difficult to obtain high resolution observations of the magnetic fields of the youngest protostars in the critical region near the protostar. The VANDAM survey is observing all known protostars in the Perseus Molecular Cloud. Here we present the polarization data of IRAS 4A. We find that with ~ 0.2'' (50 AU) resolution at λ = 8.1 and 10.3 mm, the inferred magnetic field is consistent with a circular morphology, in marked contrast with the hourglass morphology seen on larger scales. This morpho…
We present high angular resolution ($\sim$ 0.3$"$) submillimeter continuum (0.85 mm) and line observations of the O-type protostar IRAS 16547$-$4247 carried out with the Atacama Large Millimeter/Submillimeter Array (ALMA). In the 0.85 mm continuum band, the observations revealed two compact sources (with a separation of 2$"$), one of them associated with IRAS 16547$-$4247, and the other one to the west. Both sources are well resolved angularly, revealing a clumpy structure. On the other hand, the line observations revealed a rich variety of molecular species related to both continuum sources. …
It remains a key challenge to establish the molecular content of different components of low-mass protostars, like their envelopes and disks, and how this depends on the evolutionary stage and/or environment of the young stars. Observations at submillimeter wavelengths provide a direct possibility to study the chemical composition of low-mass protostars through transitions probing temperatures up to a few hundred K in the gas surrounding these sources. This paper presents a large molecular line survey of the deeply embedded protostellar binary IRAS 16293-2422 from the Submillimeter Array (SMA)…
Sub-arcsecond images of the rotational line emission of CS and SO have been obtained toward the Class I protostar IRAS 04365$+$2535 in TMC-1A with ALMA. A compact component around the protostar is clearly detected in the CS and SO emission. The velocity structure of the compact component of CS reveals infalling-rotating motion conserving the angular momentum. It is well explained by a ballistic model of an infalling-rotating envelope with the radius of the centrifugal barrier (a half of the centrifugal radius) of 50 AU, although the distribution of the infalling gas is asymmetric around the pr…
In this paper we present Combined Array for Research in Millimeter-wave Astronomy (CARMA) 3.5 mm observations and SubMillimeter Array (SMA) 870 microns observations toward the high-mass star-forming region IRAS 1816-2048, the core of the HH 80/81/80N system. Molecular emission from HCN, HCO+ and SiO is tracing two molecular outflows (the so-called Northeast and Northwest outflows). These outflows have their origin in a region close to the position of MM2, a millimeter source known to harbor a couple protostars. We estimate for the first time the physical characteristics of these molecular outf…
Low-mass protostars have been suggested to show highly variable accretion rates through-out their evolution. Such changes in accretion, and related heating of their ambient envelopes, may trigger significant chemical variations on different spatial scales and from source-to-source. We present images of emission from C17O, H13CO+, CH3OH, C34S and C2H toward the low-mass protostar IRAS 15398-3359 on 0.5" (75 AU diameter) scales with the Atacama Large Millimeter/submillimeter Array (ALMA) at 340 GHz. The resolved images show that the emission from H13CO+ is only present in a ring-like structure w…
The Class 0 protostar IRAS 16293$-$2422 Source A is known to be a binary system (A1 and A2) or even a multiple system, which processes a complex outflow structure. We have observed this source in the C$^{34}$S, SO, and OCS lines at 3.1 mm with the Atacama Large Millimeter/submillimeter Array (ALMA). A substructure of this source is traced by our high angular-resolution observation (0\farcs12; 20 au) of the continuum emission. The northwest-southeast (NW-SE) outflow on a 2\arcsec\ scale is detected in the SO ($J_N$ = $2_2$--$1_1$) line. Based on the morphology of the SO distribution, this bipol…
Much attention has been placed on the dust distribution in protostellar envelopes, but there are still many unanswered questions regarding the structure of the gas. We aim to start identifying the factors that determine the chemical structure of protostellar regions, by studying and comparing low-mass embedded systems in key molecular tracers. The cold and warm chemical structures of two embedded Class 0 systems, IRAS16293 and VLA1623 are characterized through interferometric observations. DCO+, N2H+ and N2D+ are used to trace the spatial distribution and physics of the cold regions of the env…
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…
Some evolved stars in the pre-planetary nebula phase produce highly-collimated molecular outflows that resemble the accretion-driven jets and outflows from pre-main sequence stars. We show that IRAS 16342-3814 (the Water Fountain Nebula) is such an object and present K-band integral field spectroscopy revealing a fast (> 150 km/s) bipolar H2 outflow. The H2 emission is shock excited and may arise in fast-moving clumps, accelerated by the previously observed precessing jet. The total luminosity in H2 is 0.37 L$_{\odot}$ which is comparable with that of accretion-powered outflows from Class 0 pr…
To understand the origin of the diversity observed in exoplanetary systems, it is crucial to characterize the early stages of their formation, represented by Solar-type protostars. Likely, the gaseous chemical content of these objects directly depends on the composition of the dust grain mantles formed before the collapse. Directly retrieving the ice mantle composition is challenging, but it can be done indirectly by observing the major components, such as NH3 and CH3OH at cm wavelengths, once they are released into the gas-phase during the warm protostellar stage. We observed several CH3OH an…
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）
In molecular outflows from forming low-mass protostars, most oxygen is expected to be locked up in water. However, Herschel observations have shown that typically an order of magnitude or more of the oxygen is still unaccounted for. To test if the oxygen is instead in atomic form, SOFIA-GREAT observed the R1 position of the bright molecular outflow from NGC1333-IRAS4A. The [OI] 63 um line is detected and spectrally resolved. From an intensity peak at +15 km/s, the intensity decreases until +50 km/s. The profile is similar to that of high-velocity (HV) H2O and CO 16-15, the latter observed simu…
Water is present during all stages of star formation: as ice in the cold outer parts of protostellar envelopes and dense inner regions of circumstellar disks, and as gas in the envelopes close to the protostars, in the upper layers of circumstellar disks and in regions of powerful outflows and shocks. In this paper we probe the mechanism regulating the warm gas-phase water abundance in the innermost hundred AU of deeply embedded (Class~0) low-mass protostars, and investigate its chemical relationship to other molecular species during these stages. Millimeter wavelength thermal emission from th…
Measuring the water deuterium fractionation in the inner warm regions of low-mass protostars has so far been hampered by poor angular resolution obtainable with single-dish ground- and space-based telescopes. Observations of water isotopologues using (sub)millimeter wavelength interferometers have the potential to shed light on this matter. Observations toward IRAS 16293-2422 of the 5(3,2)-4(4,1) transition of H2-18O at 692.07914 GHz from Atacama Large Millimeter/submillimeter Array (ALMA) as well as the 3(1,3)-2(2,0) of H2-18O at 203.40752 GHz and the 3(1,2)-2(2,1) transition of HDO at 225.89…
Context. The importance of the magnetic field in high-mass-star formation is not yet fully clear and there are still many open questions concerning its role in the accretion processes and generation of jets and outflows. In the past few years, masers have been successfully used to probe the magnetic field morphology and strength at scales of a few au around massive protostars, by measuring linear polarisation angles and Zeeman splitting. The massive protostar IRAS 18089-1732 is a well studied high-mass-star forming region, showing a hot core chemistry and a disc-outflow system. Previous SMA ob…
A fundamental question about the early evolution of low-mass protostars is when circumstellar disks may form. High angular resolution observations of molecular transitions in the (sub)millimeter wavelength windows make it possible to investigate the kinematics of the gas around newly-formed stars, for example to identify the presence of rotation and infall. IRAS 16293-2422 was observed with the extended Submillimeter Array (eSMA) resulting in subarcsecond resolution (0.46" x 0.29", i.e. $\sim$ 55 $\times$ 35~AU) images of compact emission from the C$^{17}$O (3-2) and C$^{34}$S (7-6) transition…
Isocyanic acid (HNCO), the most stable of the simplest molecules containing the four main elements essential for organic chemistry, has been observed in several astrophysical environments such as molecular clouds, star-forming regions, external galaxies and comets. In this work, we model HNCO spectral line profiles toward the low-mass solar type protostar IRAS 16293$-2$422 observed with the ALMA interferometer, the IRAM, JCMT and APEX single-dish radio telescopes, and the HIFI instrument on board the Herschel Space Observatory. In star-forming environments, the HNCO emission is not always in L…
Searches for the prebiotically-relevant cyanamide (NH$_2$CN) towards solar-type protostars have not been reported in the literature. We here present the first detection of this species in the warm gas surrounding two solar-type protostars, using data from the Atacama Large Millimeter/Submillimeter Array Protostellar Interferometric Line Survey (PILS) of IRAS 16293-2422 B and observations from the IRAM Plateau de Bure Interferometer of NGC1333 IRAS2A. We furthermore detect the deuterated and $^{13}$C isotopologues of NH$_2$CN towards IRAS 16293-2422 B. This is the first detection of NHDCN in th…
One of the open questions in astrochemistry is how complex organic and prebiotic molecules are formed. Aims. Our aim is to start the process of compiling an inventory of oxygen-bearing complex organic molecules toward the solar-type Class 0 protostellar binary IRAS16293-2422 from an unbiased spectral survey with ALMA (PILS). Here we focus on the new detections of ethylene oxide (c-C$_2$H$_4$O), acetone (CH$_3$COCH$_3$), and propanal (C$_2$H$_5$CHO). Methods. With ALMA, we surveyed the spectral range from 329 to 363 GHz at 0.5$"$ (60 AU diameter) resolution. Using a simple model for the molecul…
We present new spectral line observations of the CH3CN molecule in the accretion disk around the massive protostar IRAS 20126+4104 with the Submillimeter Array that for the first time measure the disk density, temperature, and rotational velocity with sufficient resolution (0.37", equivalent to ~600 AU) to assess the gravitational stability of the disk through the Toomre-Q parameter. Our observations resolve the central 2000 AU region that shows steeper velocity gradients with increasing upper state energy, indicating an increase in the rotational velocity of the hotter gas nearer the star. Su…
Methyl isocyanate (CH$_{3}$NCO) belongs to a select group of interstellar molecules considered to be relevant precursors in the formation of larger organic compounds, including those with peptide bonds. The molecule has only been detected in a couple of high-mass protostars and potentially on comets. A formation route on icy grains has been postulated for this molecule but experimental evidence is lacking. Here we extend the range of environments where methyl isocyanate is found, and unambiguously identify CH$_{3}$NCO through the detection of 43 unblended transitions in the ALMA Protostellar I…
The evolutionary past of our Solar System can be pieced together by comparing analogous low-mass protostars with remnants of our Protosolar Nebula - comets. Sulphur-bearing molecules may be unique tracers of the joint evolution of the volatile and refractory components. ALMA Band 7 data from the large unbiased Protostellar Interferometric Line Survey (PILS) are used to search for S-bearing molecules in the outer disc-like structure, 60 au from IRAS 16293-2422 B, and are compared with data on 67P/C-G stemming from the ROSINA instrument aboard Rosetta. Species such as SO$_{2}$, SO, OCS, CS, H$_{…
Observations of dust polarized emission toward star forming regions trace the magnetic field component in the plane of the sky and provide constraints to theoretical models of cloud collapse. We compare high-angular resolution observations of the submillimeter polarized emission of the low-mass protostellar source NGC 1333 IRAS 4A with the predictions of three different models of collapse of magnetized molecular cloud cores. We compute the Stokes parameters for the dust emission for the three models. We then convolve the results with the instrumental response of the Submillimeter Array observa…
We present ALMA 1.3 mm continuum, 12CO, C18O, and SO data for the Class 0 protostars, Lupus 3 MMS, IRAS 15398-3559, and IRAS 16253-2429 at resolutions of ~100 AU. By measuring a rotational profile in C18O, a 100 AU Keplerian disk around a 0.3 Msun protostar is observed in Lupus 3 MMS. No 100 AU Keplerian disks are observed in IRAS 15398-3559 and IRAS 16253-2429. Nevertheless, embedded compact (<30 AU) continuum components are detected. The C18O emission in IRAS 15398-3559 shows signatures of infall with a constant angular momentum. IRAS 16253-2429 exhibits signatures of infall and rotation, bu…
We present the results from Chandra X-ray observations, and near- and mid-infrared analysis, using VISTA/VVV and Spitzer/GLIMPSE catalogs, of the high-mass star-forming region IRAS 16562-3959, which contains a candidate for a high mass protostar. We detected 249 X-ray sources within the ACIS-I field-of-view. The majority of the X-ray sources have low count rates (< 0.638 cts/ks), and hard X-ray spectra. The search for YSOs in the region using VISTA/VVV and Spitzer/GLIMPSE catalogs resulted in a total of 799 YSOs, with 66 Class I and 733 Class II YSOs. The search for near- and mid-infrared coun…
Protostellar evolution, following the formation of the protostar is becoming reasonably well characterized, but the evolution from a prestellar core to a protostar is not well known, although the first hydrostatic core (FHSC) must be a pivotal step. NGC 1333 IRAS 4C is a potentially very young object, that we directly compare with the nearby Class 0 IRAS 4A and IRAS 4B. Observational constraints are provided by spectral imaging from the JCMT Spectral Legacy Survey (330-373 GHz) and continuum and line observations from CARMA. We present integrated intensity and velocity maps of several species,…
We have imaged 15 molecular-line emissions and the dust continuum emission around the Class 0 protostellar source, IRAS 15398-3359, with ALMA. The outflow structure is mainly traced by the H2CO (K_a=0 and 1), CCH, and CS emissions. These lines also trace the disk/envelope structure around the protostar. The H2CO (K_a=2 and 3), CH3OH, and SO emissions are concentrated toward the protostar, while the DCN emission is more extended around the protostar. We have performed the principal component analysis (PCA) for these distributions on the two different scales, the outflow and the disk/envelope st…
Our modern day Solar System has $4.6\times10^9$ yrs of evolution behind it with just a few relics of its birth conditions remaining. Comets are thought to be some of the most pristine tracers of the initial ingredients that were combined to produce the Earth and the other planets. Other low-mass protostars may be analogous to our proto-Sun and hence, could be used to study the building blocks necessary to form Solar-like systems. This study tests this idea on the basis of new high sensitivity, high spatial resolution ALMA data on the protoplanetary disc-scales (~70 au) of IRAS 16293-2422 and t…
The origin of complex organic molecules (COMs) in young Class 0 protostars has been one of the major questions in astrochemistry and star formation. While COMs are thought to form on icy dust grains via gas-grain chemistry, observational constraints on their formation pathways have been limited to gas-phase detection. Sensitive mid-infrared spectroscopy with JWST enables unprecedented investigation of COM formation by measuring their ice absorption features. We present an overview of JWST/MIRI MRS spectroscopy and imaging of a young Class 0 protostar, IRAS 15398-3359, and identify several majo…
Complex organic molecules (COM) are detected in many sources in the warm inner regions of envelopes surrounding deeply embedded protostars. Exactly how these COM form remains an open question. This study aims to constrain the formation of complex organic molecules through comparisons of their abundances towards the Class 0 protostellar binary IRAS 16293-2422 (IRAS16293). We utilised observations from the ALMA Protostellar Interferometric Line Survey of IRAS16293. The species identification and the rotational temperature and column density estimation were derived by fitting the extracted spectr…
Aims: In this paper we focus on the occurrence of glycolaldehyde (HCOCH2OH) in young solar analogs by performing the first homogeneous and unbiased study of this molecule in the Class 0 protostars of the nearby Perseus star forming region. Methods: We obtained sub-arcsec angular resolution maps at 1.3mm and 1.4mm of glycolaldehyde emission lines using the IRAM Plateau de Bure (PdB) interferometer in the framework of the CALYPSO IRAM large program. Results: Glycolaldehyde has been detected towards 3 Class 0 and 1 Class I protostars out of the 13 continuum sources targeted in Perseus: NGC1333-IR…
The GGD27 complex includes the HH 80-81-80N system, which is one of the most powerful molecular outflows associated with a high mass star-forming region observed up to now. This outflow is powered by the star associated with the source IRAS 18162-2048. Here we report the detection of continuum emission at sub-arcsec/arcsec resolution with the Submillimeter Array at 1.36mm and 456microns, respectively. We detected dust emission arising from two compact cores, MM1 and MM2, separated by about 7" (~12000AU in projected distance). MM1 spatially coincides with the powerful thermal radio continuum je…
Methyl isocyanide (CH$_3$NC) is the isocyanide with the largest number of atoms confirmed in the interstellar medium (ISM), but it is not an abundant molecule, having only been detected towards a handful of objects. Conversely, its isomer, methyl cyanide (CH$_3$CN), is one of the most abundant complex organic molecules detected in the ISM, with detections in a variety of low- and high-mass sources. We use ALMA observations from the Protostellar Interferometric Line Survey (PILS) to search for methyl isocyanide and compare its abundance with that of its isomer methyl cyanide. We use a new line …
$Aims.$ 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…
JWST Observations of Young protoStars (JOYS+): Detection of icy complex organic molecules and ions. I. CH$_4$, SO$_2$, HCOO$^-$, OCN$^-$, H$_2$CO, HCOOH, CH$_3$CH$_2$OH, CH$_3$CHO, CH$_3$OCHO, CH$_3$COOH
HH 175 is an isolated Herbig-Haro object seen towards the B35 cloud in the lambda Ori region. We use deep Subaru 8m interference filter images and Spitzer images to show that HH 175 is a terminal shock in a large collimated outflow from the nearby embedded source IRAS 05417+0907. The body of the eastern outflow lobe is hidden by a dense ridge of gas. The western outflow breaks out of the front of the cometary-shaped B35 cloud, carrying cloud fragments along, which are optically visible due to photoionization by the massive lambda Ori stars. The total extent of the bipolar outflow is 13.7 arcmi…
We have observed the Class 0 protostellar source IRAS 16293-2422 A in the C17O and H2CS lines as well as the 1.3 mm dust continuum with the Atacama Large Millimeter/submillimeter Array at an angular resolution of ~0."1 (14 au). The continuum emission of the binary component, Source A, reveals the substructure consisting of 5 intensity peaks within 100 au from the protostar. The C17O emission mainly traces the circummultiple structure on a 300 au scale centered at the intensity centroid of the continuum, while it is very weak within the radius of 50 au from the centroid. The H2CS emission, in c…
NGC 1333 IRAS 4A and IRAS 4B sources are among the best studied Stage 0 low-mass protostars which are driving prominent bipolar outflows. Most studies have so far concentrated on the colder parts (T<30K) of these regions. The aim is to characterize the warmer parts of the protostellar envelope in order to quantify the feedback of the protostars on their surroundings in terms of shocks, UV heating, photodissociation and outflow dispersal. Fully sampled large scale maps of the region were obtained; APEX-CHAMP+ was used for 12CO 6-5, 13CO 6-5 and [CI] 2-1, and JCMT-HARP-B for 12CO 3-2 emissions. …
We studied the Class I protostar 2MASS 22352345+7517076 whose dramatic brightening between the IRAS, Akari, and WISE surveys was reported by Onozato et al. (2015). 2MASS 22352345+7517076 is a member of a small group of low-mass young stellar objects, associated with IRAS 22343+7501 in the molecular cloud Lynds 1251. The IRAS, ISO, Spitzer, Akari, Herschel, and WISE missions observed different stages of its outburst. Supplemented these data with archival and our own near-infrared observations, and considering the contributions of neighbouring sources to the mid-infrared fluxes we studied the na…
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 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…
Aims: The inner regions of high-mass protostars are often invisible in the near-infrared. We aim to investigate the inner gaseous disc of IRAS11101-5829 through scattered light from the outflow cavity walls. Methods: We observed the environment of the high-mass young stellar object IRAS11101-5829 and the closest knots of its jet, HH135-136, with the VLT/SINFONI. We also retrieved archival data from the high-resolution long-slit spectrograph VLT/X-shooter. Results: We detect the first three bandheads of the $\upsilon=2-0$ CO vibrational emission for the first time in this object. It is coincide…
