A5031333688- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Molecular Spectroscopy and Structure
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Atmospheric Ozone and Climate
- Space Exploration and Technology
- Planetary Science and Exploration
- Space exploration and regulation
- History and Developments in Astronomy
- Solar and Space Plasma Dynamics
- Adaptive optics and wavefront sensing
- Spectroscopy and Laser Applications
- Isotope Analysis in Ecology
- Astronomical and nuclear sciences
- Thermodynamic properties of mixtures
- Phase Equilibria and Thermodynamics
- Spacecraft Design and Technology
- Space Science and Extraterrestrial Life
- Nuclear Physics and Applications
- Multidisciplinary Science and Engineering Research
- Calibration and Measurement Techniques
Simons Foundation
2019-2021
University of California, Berkeley
2017-2020
National Aeronautics and Space Administration
2020
Flatiron Health (United States)
2019-2020
Flatiron Institute
2019-2020
Planetary Science Institute
2018-2019
University of Hawaii System
2013-2019
University of Hawaiʻi at Mānoa
2014-2019
Lawrence Berkeley National Laboratory
2018
NASA Astrobiology Institute
2013-2014
We present the first high-resolution sub-mm survey of both dust and gas for a large population protoplanetary disks. Characterizing fundamental properties disks on statistical level is critical to understanding how evolve into diverse exoplanet population. use ALMA 89 around stars with $M_{\ast}>0.1~M_{\odot}$ in young (1--3~Myr), nearby (150--200~pc) Lupus complex. Our observations cover 890~$\mu$m continuum $^{13}$CO C$^{18}$O 3--2 lines. constrain $M_{\rm dust}$ few Martian masses...
Abstract We present Atacama Large Millimeter/Sub-Millimeter Array (ALMA) Band 6 observations of a complete sample protoplanetary disks in the young (∼1–3 Myr) Lupus star-forming region, covering 1.33 mm continuum and 12 CO, 13 C 18 O J = 2–1 lines. The spatial resolution is ∼0.″25 with medium 3 σ sensitivity 0.30 mJy, corresponding to M dust ∼ 0.2 ⊕ . apply Keplerian masking enhance signal-to-noise ratios our CO zero-moment maps, enabling measurements gas disk radii for 22 disks; we find...
The mass-luminosity relation for late-type stars has long been a critical tool estimating stellar masses. However, there is growing need both higher-precision and better understanding of systematic effects (e.g., metallicity). Here we present an empirical relationship between Mks mass spanning $0.075M_\odot<M<0.70M_\odot$. derived from 62 nearby binaries, whose orbits determine using combination Keck/NIRC2 imaging, archival adaptive optics data, literature astrometry. From their orbital...
We present an all-sky catalogue of 2970 nearby (d ≲ 50 pc), bright (J < 9) M- or late K-type dwarf stars, 86 per cent which have been confirmed by spectroscopy. This will be useful for searches Earth-size and possibly Earth-like planets future space-based transit missions ground-based infrared Doppler radial velocity surveys. Stars were selected from the SUPERBLINK proper motion according to absolute magnitudes, spectra, a combination reduced motions photometric colours. From our we...
ABSTRACT We confirm and characterize a close-in ( <?CDATA ${P}_{{\rm{orb}}}$?> <?MML <!-- <mml:math> <mml:msub> <mml:mrow> <mml:mi>P</mml:mi> </mml:mrow> <mml:mi mathvariant="normal">orb</mml:mi> </mml:msub> </mml:math> -->?> = 5.425 days), super-Neptune sized ${5.04}_{-0.37}^{+0.34}$?> <mml:msubsup> <mml:mn>5.04</mml:mn> <mml:mo>−</mml:mo> <mml:mn>0.37</mml:mn> <mml:mo>+</mml:mo> <mml:mn>0.34</mml:mn> </mml:msubsup> ${R}_{\oplus }$?> <mml:mi>R</mml:mi> <mml:mo>⊕</mml:mo> )...
We introduce the Ophiuchus DIsc Survey Employing ALMA (ODISEA), a project aiming to study entire population of Spitzer-selected protoplanetary discs in Molecular Cloud (~300 objects) from both millimeter continuum and CO isotopologues data. Here we present 1.3 mm/230 GHz images 147 targets at 0.2" (28 au) resolution typical rms 0.15 mJy. detect total 133 discs, including individual components 11 binary systems 1 triple system. Fifty-three these are spatially resolved. find clear...
The $\sigma$ Orionis cluster is important for studying protoplanetary disk evolution, as its intermediate age ($\sim$3-5 Myr) comparable to the median lifetime. We use ALMA conduct a high-sensitivity survey of dust and gas in 92 disks around members with $M_{\ast}\gtrsim0.1 M_{\odot}$. Our observations cover 1.33 mm continuum several CO $J=2-1$ lines: out sources, we detect 37 six $^{12}$CO, three $^{13}$CO, none C$^{18}$O. Using emission estimate mass, find only 11 $M_{\rm dust}\gtrsim10...
We use moderate-resolution spectra of nearby late K and M dwarf stars with parallaxes interferometrically determined radii to refine their effective temperatures, luminosities, metallicities. these revised values calibrate spectroscopic techniques infer the fundamental parameters more distant late-type stars. demonstrate that, after masking out poorly modeled regions, newest version PHOENIX atmosphere models accurately reproduce temperatures derived bolometrically. apply methods hosts...
ABSTRACT We present ten young (≲10 Myr) late-K and M dwarf stars observed in K2 Campaign 2 that host protoplanetary disks exhibit quasi-periodic or aperiodic dimming events. Their optical light curves show ∼10–20 dips flux over the 80-day observing campaign with durations of ∼0.5–2 days depths up to ∼40%. These are all members ρ Ophiuchus (∼1 Upper Scorpius (∼10 star-forming regions. To investigate nature these “dippers” we obtained: near-infrared spectra determine stellar properties...
We present a combined, homogenized analysis of archival Submillimeter Array (SMA) and Atacama Large Millimeter/submillimeter (ALMA) observations the spatially resolved 340 GHz (870 $\mu$m) continuum emission from 105 nearby protoplanetary disks. Building on previous SMA survey, we infer surface brightness profiles using simple model observed visibilities to derive luminosities ($L_{\rm mm}$) effective sizes ($R_{\rm eff}$) emission. With this sample, confirm shapes, normalizations,...
An era has started in which gas and dust can be observed independently protoplanetary disks, thanks to the recent surveys with ALMA. The first near-complete high-resolution disk survey both a single star-forming region been carried out Lupus, finding surprisingly low gas/dust ratios. goal of this work is fully exploit CO isotopologues observations comparing them physical-chemical model results, order obtain masses for large number disks. We have employed models analyze continuum Lupus...
A relation between the mass accretion rate onto central young star and of surrounding protoplanetary disk has long been theoretically predicted observationally sought. For first time, we have accurately homogeneously determined photospheric parameters, rate, for an essentially complete sample stars with disks in Lupus clouds. Our work combines results surveys conducted VLT/X-Shooter ALMA. With this dataset are able to test a basic prediction viscous theory, existence linear total mass. We...
Abstract We report the results of a ∼4 yr direct imaging survey 104 stars to resolve and characterize circumstellar debris disks in scattered light as part Gemini Planet Imager (GPI) Exoplanet Survey. targeted nearby (≲150 pc), young (≲500 Myr) with high infrared (IR) excesses ( L IR / ⋆ > 10 −5 ), including 38 previously resolved disks. Observations were made using GPI high-contrast integral field spectrograph H -band (1.6 μ m) coronagraphic polarimetry mode measure both polarized total...
The formation of planets strongly depends on the total amount as well spatial distribution solids in protoplanetary disks. Thanks to improvements resolution and sensitivity provided by ALMA, measurements surface density mm-sized grains are now possible large samples Such provide statistical constraints that can be used inform our understanding initial conditions planet formation. We analyze spatially resolved observations 36 disks Lupus star forming complex from ALMA survey at 890 micron,...
Abstract As protostars evolve from optically faint/infrared-bright (Class I) sources to bright/infrared-faint II) the solid material in their surrounding disks accumulates into planetesimals and protoplanets. The nearby, young Ophiuchus star-forming region contains hundreds of a range evolutionary states. Using Atacama Large Millimeter Array observe millimeter continuum emission, we have measured masses of, or placed strong upper limits on, dust content 279 disks. follow log-normal...
ALMA surveys have shown that CO emission in protoplanetary disks is much fainter than expected. Accordingly, CO-based gas masses and gas/dust ratios are orders of magnitude lower previously thought. This may be explained either as fast dispersal, or chemical evolution locking up volatiles larger bodies leading to the low observed fluxes. The latter processes lead enhanced C/O gas, which reflected abundances molecules like C2H. goal this work employ C2H observations understand whether fluxes...
In recent years, the disk populations in a number of young star-forming regions have been surveyed with ALMA. Understanding properties and their correlation those central star is critical to understand planet formation. particular, decrease average measured dust mass age region has observed. We conducted high-sensitivity continuum ALMA observations 43 Class II stellar objects CrA at 1.3 mm (230 GHz). The typical spatial resolution 0.3". fluxes are used estimate masses disks, survival...
We revisit the nature of large dips in flux from extinction by dusty circumstellar material that is observed Kepler for many young stars Upper Sco and ρ Oph star formation regions. These young, low-mass 'dipper' are known to have low accretion rates primarily host moderately evolved discs. Young often exhibit rotating starspots cause quasi-periodic photometric variations. found no evidence periods associated with different starspot rotation period spectrograms constructed light curves. The...
ABSTRACT Open clusters and young stellar associations are attractive sites to search for planets test theories of planet formation, migration, evolution. We present our for, characterization of, transiting in the 800 Myr old Praesepe (Beehive, M44) Cluster from K2 light curves. identify seven candidates, six which we statistically validate be real planets, last requires more data. For each host star, obtain high-resolution NIR spectra measure its projected rotational broadening radial...
Space-based missions such as Kepler, and soon TESS, provide large datasets that must be analyzed efficiently systematically. Recent work by Shallue & Vanderburg (2018) successfully used state-of-the-art deep learning models to automatically classify Kepler transit signals either exoplanets or false positives; our application of their model yielded 95.8% accuracy 95.5% average precision. Here we expand upon including additional scientific domain knowledge into the network architecture input...
Abstract The so-called dipper stars host circumstellar discs and have optical infrared light curves that exhibit quasi-periodic or aperiodic dimming events consistent with extinction by transiting dusty structures orbiting in the inner disc. Most of proposed mechanisms explaining dips – i.e. occulting disc warps, vortices, forming planetesimals assume nearly edge-on viewing geometries. However, our analysis three known dippers publicly available resolved sub-mm data reveals a range...
Transition disks with large dust cavities around young stars are promising targets for studying planet formation. Previous studies have revealed the presence of gas inside hinting at recently formed, giant planets. However, many these biased towards brightest in nearby star forming regions, and it is not possible to derive reliable statistics that can be compared exoplanet populations. We present analysis 11 transition (>20 AU radius) from a complete disk survey Lupus region, using ALMA Band...
We explore KLIP forward modeling spectral extraction on Gemini Planet Imager coronagraphic data of HR 8799, using PyKLIP and show algorithm stability with varying parameters. report new re-reduced spectrophotometry 8799 c, d, e in H & K bands. discuss a strategy for choosing optimal PSF subtraction parameters by injecting simulated sources recovering them over range The K1/K2 spectra c d are similar to previously published results from the same dataset. also present band spectrum first time...
We describe a 'super-Earth'-size (2.30 ± 0.16 R⊕) planet transiting an early K-type dwarf star in the Campaign 4 field observed by K2 mission. The host star, EPIC 210363145, was identified as candidate member of approximately 120 Myr-old Pleiades cluster based on its kinematics and photometric distance. It is rotationally variable exhibits near-ultraviolet emission consistent with age, but rotational period ≈20 d spectrum contains no Hα nor Li i absorption expected K dwarfs. Instead,...
A wide variety of ring-like dust structures has been detected in protoplanetary disks, but their origin and frequency are still unclear. We characterize the structure an extended, multi-ringed disk discovered serendipitously ALMA Lupus survey put it context population. observations Band 6 at 234 GHz 7 328 0.3" resolution toward K6 star V1094 Sco III presented, its is analyzed. The spectral index $α_{mm}$ determined inner 150 AU disk. continuum data show a very extended with two gap/ring...