A5088788014- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Molecular Spectroscopy and Structure
- Astronomy and Astrophysical Research
- Atmospheric Ozone and Climate
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Space Exploration and Technology
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Phase Equilibria and Thermodynamics
- Advanced Chemical Physics Studies
- Spectroscopy and Laser Applications
- Spacecraft and Cryogenic Technologies
- Advanced Electron Microscopy Techniques and Applications
- Advanced Causal Inference Techniques
- SAS software applications and methods
- Bayesian Modeling and Causal Inference
- Geological and Geophysical Studies
- Mental Health Research Topics
- Methane Hydrates and Related Phenomena
- Advanced Materials Characterization Techniques
- Astrophysics and Cosmic Phenomena
Northwestern University
2020-2024
National Radio Astronomy Observatory
2019-2024
Stanford Medicine
2024
University of Maryland, College Park
2022-2024
West Virginia University
2024
University of California, Santa Barbara
2023
University of California, Irvine
2023
Goddard Space Flight Center
2023
National Aeronautics and Space Administration
2023
Lake Erie College of Osteopathic Medicine
2023
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...
Abstract Investigating Protostellar Accretion (IPA) is a JWST Cycle 1 GO program that uses NIRSpec integral field units and MIRI Medium Resolution Spectrograph to obtain 2.9–28 μ m spectral cubes of young, deeply embedded protostars with luminosities 0.2–10,000 L ⊙ central masses 0.15–12 M . In this Letter, we report the discovery highly collimated atomic jet from Class 0 protostar IRAS 16253−2429, lowest-luminosity source ( bol = 0.2 ) in IPA program. The detected multiple [Fe ii ] lines...
The fine dust detected by infrared (IR) emission around the nearby β Pic analog star HD172555 is very peculiar. mineralogy composed primarily of highly refractory, nonequilibrium materials, with approximately three quarters Si atoms in silica (SiO2) species. Tektite and obsidian lab thermal spectra (nonequilibrium glassy silicas found impact magmatic systems) are required to fit data. best-fit model size distribution for observed dn/da = a−3.95±0.10. While IR photometry system has stayed...
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 the highest spatial resolution ALMA observations to date of Class I protostar GY 91 in $ρ$ Ophiuchus L1688 molecular cloud complex. Our 870 $μ$m and 3 mm dust continuum maps show that disk has a radius $\sim$80 AU, an inclination $\sim$40$^{\circ}$, but most interestingly three dark lanes located at 10 40 70 AU. model these features assuming they are gaps surface density profile find their widths 7 30 These bear striking resemblance seen HL Tau disk, suggesting there may be...
Abstract We have conducted a survey of 328 protostars in the Orion molecular clouds with Atacama Large Millimeter/submillimeter Array at 0.87 mm resolution ∼0.″1 (40 au), including observations Very 9 toward 148 ∼0.″08 (32 au). This is largest multiwavelength this by an order magnitude. use dust continuum emission and to measure disk radii masses Class 0, I, flat-spectrum protostars, characterizing evolution these properties protostellar phase. The mean for are <?CDATA...
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...
Investigating Protostellar Accretion is a Cycle 1 JWST program using the NIRSpec+MIRI integral field units to obtain 2.9--28 $\mu$m spectral cubes of five young protostars with luminosities 0.2-10,000 L$_{\odot}$ in their primary accretion phase. This paper introduces NIRSpec 2.9--5.3 data inner 840-9000 au spatial resolutions from 28-300 au. The spectra show rising continuum emission; deep ice absorption; emission H$_{2}$, H~I, and [Fe~II]; CO fundamental series absorption. Maps scattered...
The structure and composition of simple ices can be modified during stellar evolution by protostellar heating. Key to understanding the involved processes are thermal chemical tracers that diagnose history environment ice. 15.2 $\mu$m bending mode $^{12}$CO$_2$ has proven a valuable tracer ice heating events but suffers from grain shape size effects. A viable alternative is weaker $^{13}$CO$_2$ isotopologue band at 4.39 which now become accessible high S/N with $\textit{James Webb}$ Space...
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 have analyzed Spitzer and NASA/IRTF 2 - 35 \mum spectra of the warm, ~350 K circumstellar dust around nearby MS star {\eta} Corvi (F2V, 1.4 \pm 0.3 Gyr). The show clear evidence for water- carbon-rich at ~3 AU from central star, in system's Terrestrial Habitability Zone. Spectral features due to ultra-primitive cometary material were found, addition impact produced silica high temperature carbonaceous phases. At least 9 x 10^18 kg 0.1 100 warm is present a collisional equilibrium...
HD 100453AB is a 10+/-2 Myr old binary whose protoplanetary disk was recently revealed to host global two-armed spiral structure. Given the relatively small projected separation of (1.05", or ~108 au), gravitational perturbations by seemed be likely driving force behind formation arms. However, orbit these stars remained poorly understood, which prevented proper treatment dynamical influence companion on disk. We observed between 2015-2017 utilizing extreme adaptive optics systems Very Large...
The prevalence of substructures in $\sim1-10$ Myr old protoplanetary disks, which are often linked to planet formation, has raised the question how early such features form, and as a corollary, formation begins. Here we present observations seven protostellar disks (aged $\sim0.1-1$ Myr) from VLA/ALMA Nascent Disk Multiplicity Survey Orion Protostars (VANDAM: Orion) that show clear substructures, thereby demonstrating these can form lifetimes disks. We use simple analytic models well...
Abstract Class I protostars are thought to represent an early stage in the lifetime of protoplanetary disks, when they still embedded their natal envelope. Here we measure disk masses 10 Taurus Molecular Cloud constrain initial mass budget for forming planets disks. We use radiative transfer modeling produce synthetic protostar observations and fit models a multi-wavelength data set using Markov Chain Monte Carlo fitting procedure. these simultaneously our new Combined Array Research...
We characterize protostellar multiplicity in the Orion molecular clouds using ALMA 0.87~mm and VLA 9~mm continuum surveys toward 328 protostars. These observations are sensitive to projected spatial separations as small $\sim$20~au, we consider source up 10$^4$~au potential companions. The overall fraction (MF) companion (CF) for protostars 0.30$\pm$0.03 0.44$\pm$0.03, respectively, considering from 20 10$^4$~au. MFs CFs corrected contamination by unassociated young stars a probabilistic...
Abstract At least half of a protostar’s mass is accreted in the Class 0 phase, when central protostar deeply embedded dense, infalling envelope. We present first systematic search for outbursts from protostars Orion clouds. Using photometry Spitzer/IRAC spanning 2004 to 2017, we detect three with ≥2 mag changes at 3.6 or 4.5 μ m. This comparable magnitude change known protostellar FU Ori outburst. Two are newly detected bursts HOPS 12 and 124. The number detections implies that burst every...
We present Markov Chain Monte Carlo radiative transfer modeling of a joint ALMA 345 GHz and spectral energy distribution dataset for sample 97 protostellar disks from the VLA Nascent Disk Multiplicity Survey Orion Protostars. From this modeling, we derive disk envelope properties each protostar, allowing us to examine bulk population young protostars. find that are small, with median dust radius $ 29.4^{+ 4.1}_{- 2.7}$ au mass 5.8^{+ 4.6}_{- M$_{\oplus}$. no statistically significant...
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...
We present the highest spatial resolution ALMA observations to date of Class I protostar WL 17 in $\rho$ Ophiuchus L1688 molecular cloud complex, which show that it has a 12 AU hole center its disk. consider whether is actually II disk being extincted by foreground material, but find such models do not provide good fit broadband SED and also require high extinction would presumably arise from dense material close source as remnant envelope. Self-consistent embedded rotating collapsing...
Abstract The James Clerk Maxwell Telescope (JCMT) Transient Survey recently discovered that the Class 0 protostar HOPS 358 decreased in 350 GHz continuum brightness by ∼25% over course of 4 yr before brightening again for next 4. JCMT light curve can be fit a long-timescale dip lasting roughly 8 yr. A shorter-timescale periodicity is also apparent with period 1.75 and small 3% amplitude. NEOWISE monitoring reveals mid-infrared wavelength follows similar long-term pattern time. Here, we...
We present ALMA observations of the Orion Nebula that cover OMC1 outflow region. Our focus in this paper is on compact emission from protoplanetary disks. mosaicked a field containing $\sim 600$ near-IR-identified young stars, around which we can search for sub-mm tracing dusty Approximately 100 sources are known proplyds identified with HST. detect continuum at 1 mm wavelengths towards 20\%$ proplyd sample, and 8\%$ larger sample near-IR objects. The noise our maps allows 4$\sigma$...