A5034102627- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Molecular Spectroscopy and Structure
- Atmospheric Ozone and Climate
- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Phase Equilibria and Thermodynamics
- Solar and Space Plasma Dynamics
- Advanced Chemical Physics Studies
- Space Exploration and Technology
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- SAS software applications and methods
- Advanced Combustion Engine Technologies
- Atomic and Molecular Physics
- Superconducting Materials and Applications
- Advanced Thermodynamic Systems and Engines
- Spectroscopy and Laser Applications
- Superconducting and THz Device Technology
- Magnetic and Electromagnetic Effects
- Material Science and Thermodynamics
- Advanced Frequency and Time Standards
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
Institute of Astronomy and Astrophysics, Academia Sinica
2015-2024
European Southern Observatory
2017-2019
National Taiwan University
2010-2014
We present an overview of the Large Program, ``Early Planet Formation in Embedded Disks (eDisk)'', conducted with Atacama Millimeter/submillimeter Array (ALMA). The ubiquitous detections substructures, particularly rings and gaps, protoplanetary disks around T Tauri stars raise possibility that at least some planet formation may have already started during embedded stages star formation. In order to address exactly how when is initiated, program focuses on searching for substructures 12...
We report Atacama Large Millimeter/submillimeter Array (ALMA) cycle 0 observations of the C18O (J = 2–1), SO (JN 65–54), and 1.3 mm dust continuum toward L1527 IRS, a class solar-type protostar surrounded by an infalling rotating envelope. emission shows strong redshifted absorption against bright associated with strongly suggesting infall motions in The envelope also rotates velocity mostly proportional to r−1, where r is radius, whereas rotation profile at innermost radius (∼54 AU) may be...
We have conducted ALMA observations in the 1.3 mm continuum and 12CO (2-1), C18O (2-1) SO (5_6-4_5) lines toward L1489 IRS, a Class I protostar surrounded by Keplerian disk an infalling envelope. The is clearly identified emission, its outer radius (~700 AU) mass (~0.005 Msun) are comparable to those of disks around T Tauri stars. protostellar estimated be 1.6 Msun with inclination angle 66 deg. In addition disk, there blueshifted redshifted off-axis protrusions seen emission pointing north...
Subarcsecond images of the rotational line emissions CCH, CS, H2CO, and CH3OH have been obtained toward low-mass protostar IRAS 04368+2557 in L1527 as one early science projects Atacama Large Millimeter/submillimeter Array. The intensity distributions CCH CS show a double-peaked structure along edge-on envelope with dip position, whereas those H2CO are centrally peaked. By analyzing position–velocity diagrams envelope, found to reside mainly where gas is infalling conservation its angular...
Abstract While dust disks around optically visible, Class II protostars are found to be vertically thin, when and how settles the midplane unclear. As part of Atacama Large Millimeter/submillimeter Array large program, Early Planet Formation in Embedded Disks, we analyze edge-on, embedded, I protostar IRAS 04302+2247, also nicknamed “Butterfly Star.” With a resolution 0.″05 (8 au), 1.3 mm continuum shows an asymmetry along minor axis that is evidence thick geometrically disk viewed nearly...
Context. While it is generally assumed that Class II sources evolve largely in isolation from their environment, many still lie close to molecular clouds and may continue interact with them. This result late accretion of material onto the disk can significantly influence processes planet formation. Aims. In order systematically study infall gas disks, we identify candidate vicinity a reflection nebula (RN) be undergoing this process. Methods. First targeted known kilo-au scale structures -...
Abstract We present observations of the Class 0 protostar IRAS 16544–1604 in CB 68 from “Early Planet Formation Embedded Disks (eDisk)” ALMA Large program. The target continuum and lines at 1.3 mm with an angular resolution ∼5 au. image reveals a dusty protostellar disk radius ∼30 au seen close to edge-on asymmetric structures along both major minor axes. While asymmetry axis can be interpreted as effect dust flaring, comes real nonaxisymmetric structure. C 18 O cubes clearly show gas that...
We performed SMA observations in the C18O (2-1) emission line toward six Class 0 and I protostars, to study rotational motions of their surrounding envelopes circumstellar material on 100 1000 AU scales. with intensity peaks located at protostellar positions is detected all sources. The velocities as a function radius were measured from Position-Velocity diagrams perpendicular outflow directions passing through positions. Two sources, B335 NGC 1333 IRAS 4B, show no detectable motion, while...
We perform imaging and analyses of SMA 1.3 mm continuum, C18O (2-1) 12CO line data 17 Class 0 0/I protostars to study their gas kinematics on a 1,000-AU scale. Continuum emission are detected toward all the sample sources show central primary components with sizes ~600-1,500 AU associated protostars. The velocity gradients in have wide ranges orientations from parallel perpendicular outflows, magnitudes ~1 ~530 km/s/pc. construct simple kinematic model reproduce observed gradients, estimate...
We present ALMA 1.3 mm continuum, 12CO, C18O, and SO data for the Class 0 protostars, Lupus 3 MMS, IRAS 15398-3559, 16253-2429 at resolutions of ~100 AU. By measuring a rotational profile in 100 AU Keplerian disk around 0.3 Msun protostar is observed MMS. No disks are 15398-3559 16253-2429. Nevertheless, embedded compact (<30 AU) continuum components detected. The C18O emission shows signatures infall with constant angular momentum. exhibits rotation, but its unresolved. fitting our...
We have conducted ALMA cycle 2 observations in the 1.3 mm continuum and C18O (2-1) SO (5_6-4_5) lines at a resolution of ~0.3" toward Class 0 protostar B335. The continuum, C18O, emission all show central compact components with sizes ~40-180 AU within more extended components. component shows signs infalling rotational motion. By fitting simple kinematic models to data, protostellar mass is estimated be 0.05 Msun. specific angular momentum, on 100 scale, ~4.3E-5 km/s*pc. A similar ~3E-5...
We present our observational results of the 1.1 mm continuum and HCO+ (3-2) line in HL Tau at angular resolutions 0.1" obtained with ALMA data analysis 2.9 (1-0) lines disk. The Keplerian rotation disk is well resolved emission, stellar mass estimated to be 2.1+/-0.2 Msun a inclination angle 47 deg. radial profiles column density excitation temperature are measured LTE two transitions emission. An gas gap radius 30 au, where drops by factor 4-8, found profile, coincident dust traced No other...
Constraining the physical and chemical structure of young embedded disks is crucial to understanding earliest stages planet formation. As part Early Planet Formation in Embedded Disks Atacama Large Millimeter/submillimeter Array Program, we present high spatial resolution ($\sim$0$.\!\!^{\prime\prime}$1 or $\sim$15 au) observations 1.3 mm continuum $^{13}$CO $J=$ 2-1, C$^{18}$O SO $J_N=$ $6_5$-$5_4$ molecular lines toward disk around Class I protostar L1489 IRS. The emission shows a...
Abstract We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the Class I source Oph IRS 63 in context Early Planet Formation Embedded Disks large program. Our ALMA show a myriad protostellar features, such as shell-like bipolar outflow (in 12 CO), an extended rotating envelope structure 13 streamer connecting to disk C 18 O), and several small-scale spiral structures seen toward edge dust continuum SO). By analyzing velocity pattern CO O, we measure mass M ⋆ = 0.5...
Studying the physical and chemical conditions of young embedded disks is crucial to constrain initial for planet formation. Here, we present Atacama Large Millimeter/submillimeter Array (ALMA) observations dust continuum at $\sim$0.06" (8 au) resolution molecular line emission $\sim$0.17" (24 toward Class 0 protostar L1527 IRS from Program eDisk (Early Planet Formation in Embedded Disks). The smooth without substructures, but asymmetric along both major minor axes disk as previously...
Abstract Precise estimates of protostellar masses are crucial to characterize the formation stars low down brown dwarfs (BDs; M * < 0.08 ☉ ). The most accurate estimation mass uses Keplerian rotation in circumstellar disk around protostar. To apply method a protostar at low-mass end, we have observed Class 0 IRAS 16253-2429 using Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm continuum an angular resolution 0.″07 (10 au), and 12 CO, C 18 O, 13 CO ( J = 2–1), SO N 6 5 −5 4 )...
Context . Elongated trails of infalling gas, often referred to as “streamers,” have recently been observed around young stellar objects (YSOs) at different evolutionary stages. This asymmetric infall material can significantly alter star and planet formation processes, especially in the more evolved YSOs. Aims In order ascertain nature streamer-like structures then systematically characterize their dynamics, we developed code TIPSY (Trajectory Infalling Particles Streamers Young stars)....
Abstract We performed radiative transfer calculations and observing simulations to reproduce the 1.3 mm dust-continuum C 18 O (2–1) images in Class I protostar R CrA IRS7B-a, observed with ALMA Large Program “Early Planet Formation Embedded Disks (eDisk).” found that a dust disk model passively heated by central cannot peak brightness temperature of continuum emission (∼195 K), regardless assumptions about opacity. Our calculation suggests viscous accretion heating is required high...
We present combined SubMillimeter Array (SMA) + Atacama Submillimeter Telescope Experiment (ASTE) images of the Class I protobinary L1551 IRS 5 in CS ($J$ = 7--6) line, submillimeter with most complete spatial sampling ever achieved ($0''.9$ -- $36''$). The SMA image 343 GHz dust-continuum emission is also presented, which shows an elongated feature along northwest to southeast direction ($\sim$160 AU $\times$ 80 AU), perpendicular associated radio jets. SMA+ASTE show that high-velocity...
We have observed the Class I protostar TMC-1A with Atacama Millimeter/submillimeter Array (ALMA) in 12CO and C18O (J=2-1), 1.3-mm dust continuum emission. Continuum emission a deconvolved size of 0.50"x0.37", perpendicular to outflow, is detected. It most likely traces circumstellar disk around TMC-1A, as previously reported. In contrast, more extended structure detected although it still elongated 3.3"x2.2", indicating that mainly flattened envelope surrounding central protostar. shows...
We introduce a new stacking method in Keplerian disks that (1) enhances signal-to-noise ratios (S/N) of detected molecular lines and (2) makes visible otherwise undetectable weak lines. Our technique takes advantage the rotational velocity pattern. It aligns spectra according to their different centroid velocities at positions disk stacks them. After aligning, signals are accumulated narrower range as compared original line width without alignment. Moreover, originally correlated noise...
ABSTRACT We have analyzed the HCO + (1–0) data of Class I–II protostar, HL Tau, obtained from Atacama Large Millimeter/submillimeter Array long baseline campaign. generated image cube at an angular resolution ∼0.″07 (∼10 au) and performed azimuthal averaging on to enhance signal-to-noise ratio measure radial profile integrated intensity. Two gaps radii ∼28 ∼69 au a central cavity are identified in intensity profile. The inner gap is coincident with millimeter continuum radius 32 au. outer...
Understanding how material accretes onto the rotationally supported disk from surrounding envelope of gas and dust in youngest protostellar systems is important for describing disks are formed. Magnetohydrodynamic simulations magnetized, turbulent formation usually show spiral-like streams (accretion flows) connecting to disk. However, accretion flows these early stages still remain poorly characterized due their low intensity possibly some extended structures disregarded as being part...
Abstract We have observed the Class 0/I protostellar system Ced110 IRS4 at an angular resolution of 0.″05 (∼10 au) as part Atacama Large Millimeter/submillimeter Array large program, Early Planet Formation in Embedded Disks. The 1.3 mm dust continuum emission reveals that is a binary with projected separation ∼250 au. emissions associated main source and its companion, named IRS4A IRS4B, respectively, exhibit disk-like shapes likely arise from disks around protostars. has radius ∼110 au...