A5027301159- Astrophysics and Star Formation Studies
- Molecular Spectroscopy and Structure
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Galaxies: Formation, Evolution, Phenomena
- Spectroscopy and Laser Applications
- Advanced Chemical Physics Studies
- Astronomy and Astrophysical Research
- Phase Equilibria and Thermodynamics
- Astrophysical Phenomena and Observations
- Radio Astronomy Observations and Technology
- Space Exploration and Technology
- Geophysics and Gravity Measurements
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- SAS software applications and methods
- Solar and Space Plasma Dynamics
- Superconducting and THz Device Technology
- Astrophysics and Cosmic Phenomena
- Advanced Combustion Engine Technologies
- Magnetic and Electromagnetic Effects
- Spacecraft and Cryogenic Technologies
- Random lasers and scattering media
- Semiconductor Quantum Structures and Devices
Institute of Astronomy and Astrophysics, Academia Sinica
2015-2024
Kagoshima University
2016-2024
Academia Sinica
2018
National Taiwan University
2014
National Astronomical Observatory of Japan
2006-2008
The University of Tokyo
1998-2007
Sapporo Minami Hospital
2007
Center for Astrophysics Harvard & Smithsonian
2003-2007
Harvard University
2003
Misato Observatory
2002
We present Atacama Large Millimeter/submillimeter Array (ALMA) observations from the 2014 Long Baseline Campaign in dust continuum and spectral line emission HL Tau region. The images at wavelengths of 2.9, 1.3, 0.87 mm have unprecedented angular resolutions 0 075 (10 AU) to 025 (3.5 AU), revealing an astonishing level detail circumstellar disk surrounding young solar analog Tau, with a pattern bright dark rings observed all wavelengths. By fitting ellipses most distinct rings, we measure...
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...
This paper presents a large spectral line and continuum survey of 8 deeply embedded, low-mass protostellar cores using the Submillimeter Array. Each source was observed in high excitation lines some most common molecular species, CO, HCO+, CS, SO, H2CO, CH3OH SiO. Line emission from 11 species originating warm dense gas have been imaged at angular resolution (1-3"; typically 200-600 AU) together with 230 GHz (1.3 mm) 345 (0.8 mm). Compact is for all sources which likely originates marginally...
We have investigated the evolution and distribution of molecules in collapsing prestellar cores via numerical chemical models, adopting Larson-Penston solution its delayed analogs to study collapse. Molecular abundances distributions a core are determined by balance among dynamical, chemical, adsorption timescales. When central density nH with flow rises 3 × 106 cm-3, CCS CO column densities calculated show holes radius 7000 4000 AU, respectively, while N2H+ is centrally peaked. These...
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 present ~2''-4'' aperture synthesis observations of the circumstellar disk surrounding nearby young star TW Hya in CO J = 2-1 and 3-2 lines associated dust continuum obtained with partially completed Submillimeter Array. The extent peak flux 230 345 GHz emission follow closely predictions irradiated accretion model Calvet et al. resolved molecular line extends to a radius at least 200 AU, full visible scattered light, shows clear pattern Keplerian rotation. Comparison images...
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...
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...
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...
It remains a key challenge to establish the molecular content of different components low-mass protostars, like their envelopes and disks, how this depends on evolutionary stage and/or environment young stars. Observations at submillimeter wavelengths provide direct possibility study chemical composition protostars through transitions probing temperatures up few hundred K in gas surrounding these sources. This paper presents large line survey deeply embedded protostellar binary IRAS...
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 present SubMillimeter-Array observations of a Keplerian disk around the Class I protobinary system L1551 NE in 335 GHz continuum emission and submillimeter line 13CO (J=3-2) C18O at resolution ~120 x 80 AU. The 335-GHz dust-continuum image shows strong central peak closely coincident with binary protostars likely corresponding to circumstellar disks, surrounded by ~600 300 AU feature elongated approximately perpendicular [Fe II] jet from southern protostellar component suggestive...
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...
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$0.17" (24 toward Class 0 protostar L1527 IRS from Program eDisk (Early Planet Formation in Embedded Disks). The smooth without substructures, but asymmetric along both major minor axes disk as previously...
Constraining the physical and chemical structure of young embedded disks is crucial to understanding earliest stages planet formation. As part Early Planet Formation in Embedded Disks Atacama Large Millimeter/submillimeter Array Program, we present high spatial resolution ($\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...
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 )...
Arcsecond-resolution spectral observations toward the protobinary system IRAS 16293-2422 at 344 and 354 GHz were conducted using Submillimeter Array. Complex organic molecules such as CH3OH HCOOCH3 detected. Together with rich inventory revealed, it clearly indicates existence of two, rather than one, compact hot molecular cores (smaller or equal to 400 AU in radius) associated each components identified by their dust continuum emission inner star-forming core.