A5076114519- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Molecular Spectroscopy and Structure
- Astronomy and Astrophysical Research
- Astrophysical Phenomena and Observations
- High-pressure geophysics and materials
- Spacecraft and Cryogenic Technologies
- Space Exploration and Technology
- Spectroscopy and Laser Applications
- Ancient Mediterranean Archaeology and History
- Atmospheric Ozone and Climate
- Classical Antiquity Studies
- Historical and Religious Studies of Rome
- Astronomical Observations and Instrumentation
- Advanced Fiber Laser Technologies
- Advanced Combustion Engine Technologies
- Superconducting and THz Device Technology
- Archaeology and Historical Studies
- Planetary Science and Exploration
- Inertial Sensor and Navigation
- Indoor and Outdoor Localization Technologies
- Laser Design and Applications
- Magnetic Properties of Alloys
- Radio Astronomy Observations and Technology
California State University, Northridge
2018-2024
Center for Astrophysics Harvard & Smithsonian
2014-2021
University of Virginia
2019
Max Planck Institute for Astronomy
2019
Max Planck Society
2019
Utrecht University
2019
Jet Propulsion Laboratory
2018
Rice University
2017-2018
Università Campus Bio-Medico
2014-2016
California Institute of Technology
2011-2015
We introduce the Disk Substructures at High Angular Resolution Project (DSHARP), one of initial Large Programs conducted with Atacama Millimeter/submillimeter Array (ALMA). The primary goal DSHARP is to find and characterize substructures in spatial distributions solid particles for a sample 20 nearby protoplanetary disks, using very high resolution (0.035 arcsec, or 5 au FWHM) observations their 240 GHz (1.25 mm) continuum emission. These data provide first homogeneous look small-scale...
Abstract The Disk Substructures at High Angular Resolution Project (DSHARP) used ALMA to map the 1.25 mm continuum of protoplanetary disks a spatial resolution ∼5 au. We present systematic analysis annular substructures in 18 single-disk systems targeted this survey. No dominant architecture emerges from sample; instead, remarkably diverse morphologies are observed. Annular can occur virtually any radius where millimeter emission is detected and range widths few astronomical units tens...
In order to explain grain growth mm sized particles and their retention in outer regions of protoplanetary disks, as it is observed at sub-mm wavelengths, we investigate if strong inhomogeneities the gas density profiles can slow down excessive radial drift help dust grow. We use coagulation/fragmentation disk-structure models, simulate evolution a bumpy surface profile which mimic with sinusoidal disturbance. For different values amplitude length scale bumps, ability this model produce...
We present long-baseline Atacama Large Millimeter/submillimeter Array (ALMA) observations of the 870 micron continuum emission from nearest gas-rich protoplanetary disk, around TW Hya, that trace millimeter-sized particles down to spatial scales as small 1 AU (20 mas). These data reveal a series concentric ring-shaped substructures in form bright zones and narrow dark annuli (1-6 AU) with modest contrasts (5-30%). associate these features concentrations solids have had their inward radial...
Abstract The Disk Substructures at High Angular Resolution Project (DSHARP) provides a large sample of protoplanetary disks with substructures that could be induced by young forming planets. To explore the properties planets may responsible for these substructures, we systematically carry out grid 2D hydrodynamical simulations, including both gas and dust components. We present resulting structures, relationship between planet mass, as well (1) gaseous gap depth/width (2) sub/super-Keplerian...
A large fraction of the protoplanetary disks observed with ALMA display multiple well-defined and nearly perfectly circular rings in continuum, many cases substantial peak-to-valley contrast. The DSHARP campaign shows that several these are very narrow radial extent. In this paper we test hypothesis dust caused by trapping pressure bumps, if confirmed, put constraints on physics mechanism. We model process analytically 1D, assuming axisymmetry. By comparing to data, find all consistent...
We present Atacama Large Millimeter and Submillimeter Array observations of the protoplanetary disk around Herbig Ae star HD 163296 that trace spatial distribution millimeter-sized particles cold molecular gas on scales as small 25 astronomical units (A.U.). The image recorded in 1.3 mm continuum emission reveals three dark concentric rings indicate presence dust depleted gaps at about 60, 100, 160 A.U. from central star. maps CO12, CO13, CO18 J=2−1 do not show such structures but reveal a...
Gravitational forces are expected to excite spiral density waves in protoplanetary disks, disks of gas and dust orbiting young stars. However, previous observations that showed structure were not able probe disk midplanes, where most the mass is concentrated planet formation takes place. Using Atacama Large Millimeter/submillimeter Array we detected a pair trailing symmetric arms surrounding star Elias 2-27. The extend outer regions can be traced down midplane. These millimeter-wave also...
We present the most sensitive 3 mm-survey to date of protoplanetary disks carried in Taurus-Auriga star forming region (average rms about 0.3 mJy), using IRAM PdBI. With our high detection rate 17/19, we provide first detections at wavelengths longer than 1 mm for 12 sources. This enables us study statistically SED slopes and dust properties faint compare them brighter a uniform analysis method. these new data literature measurements sub-millimeter millimeter wavelengths, analyze sample 21...
Abstract Atacama Large Millimeter Array (ALMA) surveys have suggested that the dust in Class II disks may not be enough to explain averaged solid mass exoplanets, under assumption mm disk continuum emission is optically thin. This thin seems supported by recent Disk Substructures at High Angular Resolution Project (DSHARP) observations where measured optical depths are mostly less than one. However, we point out scattering can considerably reduce from an thick region. If ignored, with...
Theoretical models of grain growth predict dust properties to change as a function protoplanetary disk radius, mass, age and other physical conditions. We lay down the methodology for multi-wavelength analysis (sub-)mm cm continuum interferometric observations constrain self-consistently structure radial variation properties. The computational architecture is massively parallel highly modular. based on simultaneous fit in uv-plane at several wavelengths with model thermal emission opacity....
We present new ATCA observations at 3.3 mm of 27 young stellar objects in the rho-Oph cluster. 25 these sources have been detected. analyze sub-millimeter and millimeter SED for a subsample 17 isolated class II protoplanetary disks derive constraints on grain growth total dust mass disk outer regions. All our sample show slope which is significantly shallower than one observed ISM long wavelengths. This indicates that 1) Ophiuchus host grains grown to mm/cm-sizes their regions, 2) formation...
We present dust continuum observations of the protoplanetary disk surrounding pre-main-sequence star AS 209, spanning more than an order magnitude in wavelength from 0.88 to 9.8 mm. The was observed with subarcsecond angular resolution (02–05) investigate radial variations its properties. At longer wavelengths, emission structure is notably compact, providing model-independent evidence for changes grain properties across disk. find that physical models which reproduce require a dependence...
Abstract We analyze high angular resolution ALMA observations of the TW Hya disk to place constraints on CO and dust properties. present new, sensitive 12 J = 3 − 2 line at a spatial 8 au (0.″14). The emission exhibits bright inner core, shoulder r ≈ 70 au, prominent break in slope 90 au. Radiative transfer modeling is used demonstrate that morphology can be reasonably reproduced with column density profile featuring steep decrease 15 secondary bump peaking Similar features have been...
ABSTRACT We present ALMA observations of 106 G-, K-, and M-type stars in the Upper Scorpius OB Association hosting circumstellar disks. With these data, we measure 0.88 mm continuum 12 CO J = 3–2 line fluxes disks around low-mass (0.14–1.66 M ⊙ ) at an age 5–11 Myr. Of 75 primordial sample, 53 are detected dust 26 CO. 31 classified as debris/evolved transitional disks, five none The lack emission approximately half with can be explained if is optically thick but has a compact emitting area...
Theory predicts that giant planets and low mass stellar companions shape circumstellar disks by opening annular gaps in the gas dust spatial distribution. For more than a decade it has been debated whether this is dominant process leads to formation of transitional disks. In paper, we present millimeter-wave interferometric observations disk around young intermediate star LkHa330. These reveal lopsided ring 1.3 mm thermal emission characterized radius about 100 AU an azimuthal intensity...
Transitional disks (TDs) are thought to be a late evolutionary stage of protoplanetary with dust depleted inner regions. The mechanism responsible for this depletion is still under debate. To constrain the models it mandatory have good understanding properties gas content disk. Using X-Shooter broad band -UV NIR- medium resolution spectroscopy we derive stellar, accretion, and wind sample 22 TDs. analysis these allows us put strong constraints on in region very close star (<0.2 AU) which...
Context. Observations at sub-millimeter and mm wavelengths will in the near future be able to resolve radial dependence of spectral slope circumstellar disks with a resolution around few AU distance closest star-forming regions. Aims. We aim constrain physical models grain growth fragmentation by large sample (sub-)mm observations pre-main sequence stars Taurus-Auriga Ophiuchus Methods. State-of-the-art coagulation/fragmentation disk-structure codes are coupled produce steady-state size...
We present ALMA 850 $\mu$m continuum observations of the Orion Nebula Cluster that provide highest angular resolution ($\sim 0\rlap{.}''1 \approx 40$ AU) and deepest sensitivity 0.1$ mJy) region to date. mosaicked a field containing $\sim 225$ optical or near-IR-identified young stars, 60$ which are also optically-identified "proplyds". detect emission at towards 80$% proplyd sample, 50$% larger sample previously-identified cluster members. Detected objects have fluxes 0.5$-80 mJy. remove...
We present new results from the Disks@EVLA program for two young stars: CY Tau and DoAr 25. trace continuum emission arising their circusmtellar disks spatially resolved observations, down to tens of AU scales, at {\lambda} = 0.9, 2.8, 8.0, 9.8 mm DoAr25 1.3, 7.1 Tau. Additionally, we constrain amount whose origin is different thermal dust 5 cm observations. Directly interferometric data, find that observations 7 1 a compact disk while millimeter-wave an extended structure. From physical...
We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of protoplanetary disks ("proplyds") in the Orion Nebula Cluster. imaged five individual fields at 856 μm containing 22 Hubble Space Telescope (HST)-identified proplyds and detected 21 them. Eight those were for first time submillimeter wavelengths, including most prominent, well-known proplyd entire Nebula, 114–426. Thermal dust emission excess any free–free component was measured all but one disks, ranged between 1...
We present ALMA observations of the 0.88 millimeter dust continuum, 13CO, and C18O J=3-2 line emission circumbinary disk HD142527 at a spatial resolution about 0.25". This system is characterized by large central cavity roughly 120 AU in radius, asymmetric gas emission. By comparing with theoretical models, we find that azimuthal variations density reach contrast 54 for grains 3.75 CO molecules, an extreme gas-to-dust ratio 1.7 on crescent. point out caution required interpreting continuum...
For over a decade, the structure of inner cavity in transition disk TW Hydrae has been subject debate. Modeling with data obtained at different wavelengths led to variety proposed structures. Rather than being inconsistent, individual models might point faces physical processes going on disks, such as dust growth and planet formation. Our aim is investigate again find what extent we can reconcile apparent model differences. A large set high-angular-resolution was collected from near-infrared...