Temperature is a crucial parameter in circumstellar disk evolution and planet formation, because it governs the resistance of the gas to gravitational instability and sets the chemical composition of the planet-forming material. We set out to determine the gas temperature of the young disk-like structure around the Class 0 protostar IRAS 16293$-$2422A. We use Atacama Large Millimeter/submillimeter Array (ALMA) observations of multiple H$_2$CS $J=7-6$ and $J=10-9$ lines from the Protostellar Interferometric Line Survey (PILS) to create a temperature map for the inner $\sim$200 AU of the disk-like structure. This molecule is a particularly useful temperature probe because transitions between energy levels with different $K_{\rm{a}}$ quantum numbers operate only through collisions. Based on the H$_2$CS line ratios, the temperature is between $\sim$100$-$175 K in the inner $\sim$150 AU, and drops to $\sim$75 K at $\sim$200 AU. At the current resolution (0.5$^{\prime\prime} \sim$70 AU), no jump is seen in the temperature at the disk-envelope interface. The temperature structure derived from H$_2$CS is consistent with envelope temperature profiles that constrain the temperature from 1000 AU scales down to $\sim$100 AU, but does not follow the temperature rise seen in these profiles at smaller radii. Higher angular resolution observations of optically thin temperature tracers are needed to establish whether cooling by gas-phase water, the presence of a putative disk or the dust optical depth influences the gas temperature at $\lesssim$100 AU scales. The temperature at 100 AU is higher in IRAS 16293A than in the embedded Class 0/I disk L1527, consistent with the higher luminosity of the former.
Debris disks around stars are considered as components of planetary systems. Constrain the dust properties of these disks can give crucial information to formation and evolution of planetary systems. As an all-sky survey, \textit{InfRared Astronomical Satellite} (\iras) gave great contribution to the debris disk searching which discovered the first debris disk host star (Vega). The \iras-detected debris disk sample published by Rhee \citep{rhe07} contains 146 stars with detailed information of dust properties. While the dust properties of 45 of them still can not be determined due to the limit…
IRAS 20050+2720 is young star forming region at a distance of 700 pc without apparent high mass stars. We present results of our multiwavelength study of IRAS 20050+2720 which includes observations by Chandra and Spitzer, and 2MASS and UBVRI photometry. In total, about 300 YSOs in different evolutionary stages are found. We characterize the distribution of young stellar objects (YSOs) in this region using a minimum spanning tree (MST) analysis. We newly identify a second cluster core, which consists mostly of class II objects, about 10 arcmin from the center of the cloud. YSOs of earlier evolu…
We report the discovery of a new young stellar cluster in the outer Galaxy located at the position of an IRAS PSC source that has been previously mis-identified as an external galaxy. The cluster is seen in our near-infrared imaging towards IRAS 04186+5143 and in archive Spitzer images confirming the young stellar nature of the sources detected. There is also evidence of sub-clustering seen in the spatial distributions of young stars and of gas and dust. Near- and mid-infrared photometry indicates that the stars exhibit colours compatible with reddening by interstellar and circumstellar dust a…
Resolved submillimeter imaging of transitional disks is increasingly revealing the complexity of disk structure. Here we present the first high-resolution submillimeter image of a recently identified transitional disk around IRAS 04125+2902 in the Taurus star-forming region. We measure an inner disk hole of ~20 AU around IRAS 04125+2902 by simultaneously modeling new 880 micron Submillimeter Array (SMA) data along with an existing spectral energy distribution supplemented by new Discovery Channel Telescope (DCT) photometry. We also constrain the outer radius of the dust disk in IRAS~04125+2902…
We have analyzed ALMA Cycle 5 data in Band 4 toward three low-mass young stellar objects (YSOs), IRAS 03235+3004 (hereafter IRAS 03235), IRAS 03245+3002 (IRAS 03245), and IRAS 03271+3013 (IRAS 03271), in the Perseus region. The HC$_{3}$N ($J=16-15$; $E_{\rm {up}}/k = 59.4$ K) line has been detected in all of the target sources, while four CH$_{3}$OH lines ($E_{\rm {up}}/k = 15.4-36.3$ K) have been detected only in IRAS 03245. Sizes of the HC$_{3}$N distributions ($\sim 2930-3230$ au) in IRAS 03235 and IRAS 03245 are similar to those of the carbon-chain species in the warm carbon chain chemistr…
Jets and outflows are associated with young stellar objects across the stellar mass spectrum, from brown dwarf protostars to massive, Ae/Be stars. Frequently, the jet morphology is spatially discontinuous because of the temporal variability of the ejection from the driving source. Images covering a wide field of view around the jet driving-source are useful to map the large-scale jet emission and to explore the mass ejection history. The aim of this work was to search for large-scale optical Herbig-Haro (HH) objects lying in a wide field around a sample of IRAS sources, candidates to trace you…
We report the results of spectroscopic observations and numerical modelling of the H II region IRAS 18153-1651. Our study was motivated by the discovery of an optical arc and two main-sequence stars of spectral type B1 and B3 near the centre of IRAS 18153-1651. We interpret the arc as the edge of the wind bubble (blown by the B1 star), whose brightness is enhanced by the interaction with a photoevaporation flow from a nearby molecular cloud. This interpretation implies that we deal with a unique case of a young massive star (the most massive member of a recently formed low-mass star cluster) c…
We present the results of a spectroscopic analysis and spectral energy distribution (SED) modelling of the optical counterpart of the infrared source IRAS 22150+6109. The source was suggested to be as a Herbig Be star located in the star forming region L 1188. Absorption lines in the optical spectrum indicate a spectral type B3, while weak Balmer emission lines reflect the presence of a circumstellar gaseous disc. The star shows no excess radiation in the near-infrared spectral region and a strong excess in the far-infrared that we interpret as radiation from a large disc, whose inner edge is …
We present high-angular-resolution {\it Hubble Space Telescope (HST)} optical and near-infrared imaging of the compact planetary nebula (PN) IRAS 21282+5050. Optical images of this object reveal several complex morphological structures including three pairs of bipolar lobes and an elliptical shell lying close to the plane of the sky. From near-infrared observations, we found a dust torus oriented nearly perpendicular to the major axis of elliptical shell. The results suggest that IRAS 21282+5050 is a multipolar PN, and these structures developed early during the post asymptotic-giant-branch (A…
We present early results of our multiwavelength study of the star forming region IRAS 20050+2720. While we use X-rays and IR to classify young stellar objects, the optical data can be used to exclude foreground objects. The dataset set contains 57 class I sources, 183 class II sources and 183 X-ray sources, of which 140 are class III candidates. Within IRAS 20050+2720 four subclusters are found. Subcluster A and B are the densest regions, which contain stars of all evolutionary stages. Subcluster C is much younger than the other two. It has not formed any class III objects yet. We newly identi…
We report the discovery of a small aggregate of young stars seen in high-resolution, deep near-infrared ($JHK_S$) images towards IRAS 06345-3023 in the outer Galaxy and well below the mid-plane of the Galactic disc. The group of young stars is likely to be composed of low-mass stars, mostly Class I young stellar objects. The stars are seen towards a molecular cloud whose CO map peaks at the location of the IRAS source. The near-infrared images reveal, additionally, the presence of nebular emission with rich morphological features, including arcs in the vicinity of embedded stars, wisps and bri…
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…
Using the 13.7 m telescope of Purple Mountain Observatory (PMO), a survey of J=1-0 lines of CO and its isotopes was carried out towards 98 methanol maser sources in January 2008. Eighty-five sources have infrared counterparts within one arcmin. In the survey, except 43 sources showing complex or multiple-peak profiles, almost all the $^{13}$CO line profiles of the other 55 sources have large line widths of 4.5 km s$^{-1}$ on average and are usually asymmetric. Fifty corresponding Infrared Astronomical Satellite (IRAS) sources of these 55 sources are with $L_{bol}$ larger than $10^{3}L_{\odot}$…
We present and analyze two new high-resolution (approx 0.3 arcsec), high-sensitivity (approx 50 uJy beam-1) Very Large Array 3.6 cm observations of IRAS 16293-2422 obtained in 2007 August and 2008 December. The components A2alpha and A2beta recently detected in this system are still present, and have moved roughly symmetrically away from source A2 at a projected velocity of 30-80 km s-1. This confirms that A2alpha and A2beta were formed as a consequence of a very recent bipolar ejection from A2. Powerful bipolar ejections have long been known to occur in low-mass young stars, but this is -to o…
Deeply embedded protostars are actively fed from their surrounding envelopes through their protostellar disk. The physical structure of such early disks might be different from that of more evolved sources due to the active accretion. We present 1.3 and 3\,mm ALMA continuum observations at resolutions of 6.5\,au and 12\,au respectively, towards the Class 0 source IRAS 16293-2422 B. The resolved brightness temperatures appear remarkably high, with $T_{\rm b} >$ 100\,K within $\sim$30\,au and $T_{\rm b}$ peak over 400\,K at 3\,mm. Both wavelengths show a lopsided emission with a spectral index r…
We present an analysis of the IRAS 08589-4714 star-forming region. This region harbors candidate young stellar objects identified in the WISE and Herschel images using color index criteria and spectral energy distributions (SEDs). The SEDs of some of the infrared sources and the 70 microns radial intensity profile of the brightest source (IRS 1) are modeled from Herschel fluxes using the one-dimensional radiative transfer DUSTY code. For these objects, we estimate the envelope masses, sizes, densities, and luminosities which suggest that they are very young, massive and luminous objects at ear…
Four binary objects and one triplet have been revealed in the young stellar cluster located in the vicinity of IRAS 05137+3919 source on a distance 4.4 kpc with the use of statistic analysis. They are including the pair of AeBe stars. The percentage of the multiple systems in the cluster is mf = 5 and cp = 10.The mass of the multiple systems' components are located in the range from 1 to 8 Msol and log P (rotation period in years) - from 4.4 to 4.7. The median value of the mass ratio of the components is q = 0.86. The percentage of the multiple systems and their parameters in this cluster is r…
We present results of AO-assisted K-band IFU spectroscopy of the massive young star IRAS13481-6124 performed with ESO's VLT/SINFONI instrument. Our spectro-astrometric analysis of the Brγ line revealed a photo-center shift with respect to the adjacent continuum of \sim1 AU at a distance of 3.1 kpc. The position angle of this shift matches with that of the outflow which confirms that the massive star is indeed the driving source. Furthermore, a velocity gradient along the major disk axis was found which hints at the rotational sense of the ionized region, and thus of the disk as well. The gradi…
We present 3 mm ALMA continuum and line observations at resolutions of 6.5 au and 13 au respectively, toward the Class 0 system IRAS 16293-2422 A. The continuum observations reveal two compact sources towards IRAS 16293-2422 A, coinciding with compact ionized gas emission previously observed at radio wavelengths (A1 and A2), confirming the long-known radio sources as protostellar. The emission towards A2 is resolved and traces a dust disk with a FWHM size of ~12 au, while the emission towards A1 sets a limit to the FWHM size of the dust disk of ~4 au. We also detect spatially resolved molecula…
The chemical evolution of a star- and planet-forming system begins in the prestellar phase and proceeds across the subsequent evolutionary phases. The chemical trail from cores to protoplanetary disks to planetary embryos can be studied by comparing distant young protostars and comets in our Solar System. One particularly chemically rich system that is thought to be analogous to our own is the low-mass IRAS 16293-2422. ALMA-PILS observations have made the study of chemistry on the disk scales (< 100 AU) of this system possible. Under the assumption that comets are pristine tracers of the outer…
We present a comprehensive multiwavelength investigation of a likely massive young cluster `IRAS 05100+3723' and its environment with the aim to understand its formation history and feedback effects. We find that IRAS 05100+3723 is a distant ($\sim$3.2 kpc), moderate mass ($\sim$500 \msun), young ($\sim$3 Myr) cluster with its most massive star being an O8.5V-type. From spectral modeling, we estimate the effective temperature and log $g$ of the star as $\sim$33,000 K and $\sim$3.8, respectively. Our radio continuum observations reveal that the star has ionized its environment forming an HII re…
We present new spectral line observations of the CH3CN molecule in the accretion disk around the massive protostar IRAS 20126+4104 with the Submillimeter Array that for the first time measure the disk density, temperature, and rotational velocity with sufficient resolution (0.37", equivalent to ~600 AU) to assess the gravitational stability of the disk through the Toomre-Q parameter. Our observations resolve the central 2000 AU region that shows steeper velocity gradients with increasing upper state energy, indicating an increase in the rotational velocity of the hotter gas nearer the star. Su…
IRAS 16293-2422 is a very well studied young stellar system seen in projection towards the L1689N cloud in the Ophiuchus complex. However, its distance is still uncertain with a range of values from 120 pc to 180 pc. Our goal is to measure the trigonometric parallax of this young star by means of H$_2$O maser emission. We use archival data from 15 epochs of VLBA observations of the 22.2 GHz water maser line. By modeling the displacement on the sky of the H$_2$O maser spots, we derived a trigonometric parallax of $7.1\pm1.3$ mas, corresponding to a distance of $141_{-21}^{+30}$ pc. This new dis…
ALMA's sharpest view of IRAS 08544-4431: Unveiling the dust distribution asymmetries in the circumbinary disk
Macquarie University（麦考瑞大学）；INAF, Osservatorio Astronomico di Roma（意大利国家天体物理研究所罗马天文台）；ATNF, CSIRO, Space and Astronomy（澳大利亚联邦科学与工业研究组织空间与天文部射电天文国家设施）；KU Leuven（荷语鲁汶大学）
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…
We present Submillimeter Array observations of the young stellar object IRAS 04579+4703 in the 1.3 mm continuum and in the 12CO(2-1), 13CO(2-1) and C18O(2-1) lines. The 1.3 mm continuum image reveals a flattened structure with a mass of 13 Msun. The 12CO(2-1) line map and position-velocity (PV) diagram, together with the broad wing (full width=30 km/s of 12CO(2-1)) line, clearly show that there is an outflow motion, which originates from an embedded massive YSO in this region. The lengths of the blue-shifted and red-shifted lobes are 0.14 pc and 0.13 pc respectively. The total gas mass, averag…
We present an analysis of HCO+ (J=3-2) and H13CO+ (J=3-2) observations of the massive (M ~ 20 Msun) submm/IR source IRAS 01202+6133 located on the periphery of the HII region KR 120 (Sh 2-187). The HCO+ line profile has a classic blue-asymmetric shape with the optically thin H13CO+ line peaking at the position expected if the HCO+ line arises from a combination of self-absorption and infall motion. We have modified existing analytic radiative transfer models to allow for the fitting of submm/mm line profiles that have both self-absorption features and optically thin wings and applied these mod…
Context: Post-Asymptotic Giant Branch (AGB) binaries are surrounded by stable dusty and gaseous disks similar to the ones around young stellar objects. Whereas significant effort is spent on modeling observations of disks around young stellar objects, the disks around post-AGB binaries receive significantly less attention, even though they pose significant constraints on theories of disk physics and binary evolution. Aims: We want to examine the structure of and phenomena at play in circumbinary disks around post-AGB stars. We continue the analysis of our near-infrared interferometric image of…
Dust polarization in millimeter (and centimeter) has been mapped in disks around an increasing number of young stellar objects. It is usually thought to come from emission by magnetically aligned (non-spherical) grains, but can also be produced by dust scattering. We present a semi-analytic theory of disk polarization that includes both the direction emission and scattering, with an emphasis on their relative importance and how they are affected by the disk inclination. For face-on disks, both emission and scattering tend to produce polarization in the radial direction, making them difficult t…
We present several molecular line emission arcsec and subarcsec observations obtained with the Submillimeter Array (SMA) in the direction of the massive protostar IRAS 18162-2048, the exciting source of HH 80-81. The data clearly indicates the presence of a compact (radius~425-850 AU) SO2 structure, enveloping the more compact (radius~150 AU) 1.4 millimeter dust emission (reported in a previous paper). The emission spatially coincides with the position of the prominent thermal radio jet which terminates at the HH 80-81 and HH 80N Herbig-Haro objects. Furthermore, the molecular emission is elon…
We performed the new JVLA full polarization observations at 40-48 GHz (6.3-7.5 mm) towards the nearby ($d$ $=$147$\pm$3.4 pc) Class 0 YSO IRAS 16293-2422, and compare with the previous SMA observations reported by Rao et al. (2009; 2014). We observed the quasar J1407+2827 which is weakly polarized and can be used as a leakage term calibrator for $<$9 GHz observations, to gauge the potential residual polarization leakage after calibration. We did not detect Stokes Q, U, and V intensities from the observations of J1407+2827, and constrain (3-$σ$) the residual polarization leakage after calibrati…
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$143 AU) at 8 mm, 1 cm, and 4 cm. These 2 sources (IRAS2A VLA1 and VLA2) are likely driving the two orthogonal outflows known to originate from IRAS2A. The…
We present a time-variability study of young stellar objects in the cluster IRAS 20050+2720, performed at 3.6 and 4.5 micron with the Spitzer Space Telescope; this study is part of the Young Stellar Object VARiability project (YSOVAR). We have collected light curves for 181 cluster members over 40 days. We find a high variability fraction among embedded cluster members of ca. 70%, whereas young stars without a detectable disk display variability less often (in ca. 50% of the cases) and with lower amplitudes. We detect periodic variability for 33 sources with periods primarily in the range of 2…
Outbursts of young stellar objects occur when the mass accretion rate suddenly increases. However, such outbursts are difficult to detect for deeply embedded protostars due to their thick envelope and the rarity of outbursts. The near-IR spectroscopy is a useful tool to identify ongoing outburst candidates by the characteristic absorption features that indicate a disk origin. However, without high-resolution spectroscopy, the spectra of outburst candidates can be confused with the late-type stars since they have similar spectral features. For the protostar IRAS 16316-1540, the near-IR spectrum…
Based on the long-term monitoring data of the water maser since 2019.0 to 2021.0 allowed us detecting in IRAS 16293-2422 two powerful phenomena lasted about year at radial velocities near 6 and 8 km s$^{-1}$. In both cases, powerful short flares were located on the tops of less powerful, but more prolonged ones (2.5 and 0.5 kJy), radiation of which initiated the emission of more powerful flares. For the first time, configurations of several emitting maser spots located at the line of sight to the observer were discovered experimentally. This made it possible to confirm the hypothesis of activa…
We performed Herschel observations of the continuum and line emission from the high-mass star-forming region IRAS20126+4104, which hosts a well-studied B-type (proto)star powering a bipolar outflow and is associated with a Keplerian circumstellar disk. The continuum images at six wavelengths allowed us to derive an accurate estimate of the bolometric luminosity and mass of the molecular clump enshrouding the disk. The same region has been mapped in 12 rotational transitions of carbon monoxide, which were used in synergy with the continuum data to determine the temperature and density distribut…
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…
Early Planet Formation in Embedded Disks (eDisk). VIII. A Small Protostellar Disk around the Extremely Low-Mass and Young Class 0 Protostar, IRAS 15398-3359
Context. The Class 0 protostellar binary IRAS 16293-2422 is an interesting target for (sub)millimeter observations due to, both, the rich chemistry toward the two main components of the binary and its complex morphology. Its proximity to Earth allows the study of its physical and chemical structure on solar system scales using high angular resolution observations. Such data reveal a complex morphology that cannot be accounted for in traditional, spherical 1D models of the envelope. Aims. The purpose of this paper is to study the environment of the two components of the binary through 3D radiat…
IRAS 20126+4104 is one of the best candidates for a high-mass (proto)star surrounded by an accretion disk. Such a fact may be used to set constraints on theories of high-mass star formation, but requires confirmation that the mass and luminosity of IRAS 20126+4104 are indeed typical of a B0.5 star, which in turn requires an accurate estimate of the distance. We used the Very Long Baseline Array and the European VLBI Network to observe the 22.2 GHz water and 6.7 GHz methanol masers in IRAS 20126+4104 at a number of epochs suitably distributed in time. The absolute positions of the maser feature…
Changing physical conditions in the vicinity of protostars allow for a rich and interesting chemistry to occur. Heating and cooling of the gas allows molecules to be released from and frozen out on dust grains. These changes in physics, traced by chemistry, as well as the kinematical information allows us to distinguish between different scenarios describing the infall of matter and the launching of molecular outflows and jets. We aim at determining the spatial distribution of different species, of different chemical origin. This is to examine the physical processes in play in the observed reg…
The luminous Young Stellar Object (YSO) IRAS 07422-2001 is studied in the infrared. We discover star forming activity in embedded clusters located in a cloud detected at mid-IR wavelengths in emission. Multiple outflows are discovered from these clusters in the H_2 ro-vibrational line at 2.122 micron. We detect at least six outflows from the cluster associated with the IRAS source and another outflow from a source located in a cluster detected ~2.7 arcmin NE of the IRAS source. Additional star formation is taking place in two other cluster candidates within the cloud. Three of the YSOs in the …
Aims. We report the discovery of a strong outburst of the embedded young stellar object (YSO), namely UKIDSS-J185318.36+012454.5, located in the star-forming region associated with IRAS 18507+0121 source and GAL 034.4+00.23 HII region. Methods. Using the archival photometric data and images we determined the amplitude and the epoch of the outburst, as well as the evolution stage and the basic parameters of the object. Results. According to the near and mid-infrared colors and spectral energy distribution, we classify the object as an intermediate-mass young stellar object (YSO) with Class 0/I …
We are studying a class of binary post-AGB stars that seem to be systematically surrounded by equatorial disks and slow outflows. Although the rotating dynamics had only been well identified in three cases, the study of such structures is thought to be fundamental to the understanding of the formation of nebulae around evolved stars. We present ALMA maps of 12CO and 13CO J=3-2 lines in one of these sources, IRAS08544-4431. We analyzed the data by means of nebula models, which account for the expectedly composite source and can reproduce the data. From our modeling, we estimated the main nebula…
Context: Protostellar jets in high-mass young stellar objects (HMYSOs) play a key role in the understanding of star formation and provide us with an excellent tool to study fundamental properties of HMYSOs. Aims: We aim at studying the physical and kinematic properties of the near-IR (NIR) jet of IRAS\,13481-6124 from au to parsec scales. Methods: Our study includes NIR data from the Very Large Telescope instruments SINFONI, CRIRES, and ISAAC. Information about the source and its immediate environment is retrieved with SINFONI. The technique of spectro-astrometry is performed with CRIRES to st…
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. …
There is a class of binary post-AGB stars with a remarkable near-infrared excess that are surrounded by Keplerian or quasi-Keplerian disks and extended outflows composed of gas escaping from the disk. The Keplerian dynamics had been well identified in four cases, namely the Red Rectangle, AC Her, IW Car, and IRAS 08544-4431. In these objects, the mass of the outflow represents ~ 10 % of the nebular mass, the disk being the dominant component of the nebula. We present interferometric NOEMA maps of 12CO and 13CO J=2-1 in 89 Her and 12CO J=2-1 in AC Her, IRAS 19125+0343, and R Sct. Several proper…
Molecular outflows from high-mass young stellar objects provide an excellent way to study the star formation process, and investigate if they are scaled-up versions of their low-mass counterparts. We selected the nearby massive star forming region IRAS 17233-3606 in order to study the kinematics and physics along the molecular outflow(s) originating from this source. We observed IRAS 17233-3606 in CO, a typical tracer of gas associated with molecular outflow, with the Submillimeter Array in the (2-1) transition, and with the APEX telescope in the higher excitation (6-5) line. Additional infrar…
