Malavika Vasist
A5025004841- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Adaptive optics and wavefront sensing
- Spectroscopy and Laser Applications
- Astronomical Observations and Instrumentation
- Target Tracking and Data Fusion in Sensor Networks
- Gamma-ray bursts and supernovae
- Reservoir Engineering and Simulation Methods
University of Liège
2022-2024
We present the highest fidelity spectrum to date of a planetary-mass object. VHS 1256 b is $<$20 M$_\mathrm{Jup}$ widely separated ($\sim$8\arcsec, = 150 au), young, companion that shares photometric colors and spectroscopic features with directly imaged exoplanets HR 8799 c, d, e. As an L-to-T transition object, exists along region color-magnitude diagram where substellar atmospheres from cloudy clear. observed 1256~b \textit{JWST}'s NIRSpec IFU MIRI MRS modes for coverage 1 $\mu$m 20 at...
We present JWST Early Release Science (ERS) coronagraphic observations of the super-Jupiter exoplanet, HIP 65426 b, with Near-Infrared Camera (NIRCam) from 2-5 $\mu$m, and Mid-Infrared Instrument (MIRI) 11-16 $\mu$m. At a separation $\sim$0.82" (86$^{+116}_{-31}$ au), b is clearly detected in all seven our observational filters, representing first images an exoplanet to be obtained by JWST, ever direct detection beyond 5 These demonstrate that exceeding its nominal predicted performance up...
The direct characterization of exoplanetary systems with high contrast imaging is among the highest priorities for broader exoplanet community. As large space missions will be necessary detecting and characterizing exo-Earth twins, developing techniques technology exoplanets a driving focus For first time, JWST directly observe extrasolar planets at mid-infrared wavelengths beyond 5$\mu$m, deliver detailed spectroscopy revealing much more precise chemical abundances atmospheric conditions,...
Retrieving the physical parameters from spectroscopic observations of exoplanets is key to understanding their atmospheric properties. Exoplanetary retrievals are usually based on approximate Bayesian inference and rely sampling-based approaches compute parameter posterior distributions. Accurate or repeated retrievals, however, can result in very long computation times due sequential nature algorithms. We aim amortize exoplanetary retrieval using neural estimation (NPE), a simulation-based...
With a temperature of ∼285 K, WISEJ0855–0714 (hereafter, WISE 0855) is the coldest brown dwarf observed thus far. Studying such cold gas giants allows us to probe atmospheric physics and chemistry evolved objects that resemble Solar System giants. Using James Webb Space Telescope (JWST), we obtained observations characterize 0855's atmosphere, focusing on vertical variation in water steam abundance, measuring trace abundances, obtaining bulk parameters for this object. We ultra-cool 0855...
We present the highest fidelity spectrum to date of a planetary-mass object. VHS 1256 b is $<$20 M$_\mathrm{Jup}$ widely separated ($\sim$8\arcsec, = 150 au), young, companion that shares photometric colors and spectroscopic features with directly imaged exoplanets HR 8799 c, d, e. As an L-to-T transition object, exists along region color-magnitude diagram where substellar atmospheres from cloudy clear. observed 1256~b \textit{JWST}'s NIRSpec IFU MIRI MRS modes for coverage 1 $μ$m 20 at...
The direct characterization of exoplanetary systems with high contrast imaging is among the highest priorities for broader exoplanet community. As large space missions will be necessary detecting and characterizing exo-Earth twins, developing techniques technology exoplanets a driving focus For first time, JWST directly observe extrasolar planets at mid-infrared wavelengths beyond 5$μ$m, deliver detailed spectroscopy revealing much more precise chemical abundances atmospheric conditions,...
We present JWST Early Release Science (ERS) coronagraphic observations of the super-Jupiter exoplanet, HIP 65426 b, with Near-Infrared Camera (NIRCam) from 2-5 $μ$m, and Mid-Infrared Instrument (MIRI) 11-16 $μ$m. At a separation $\sim$0.82" (86$^{+116}_{-31}$ au), b is clearly detected in all seven our observational filters, representing first images an exoplanet to be obtained by JWST, ever direct detection beyond 5 These demonstrate that exceeding its nominal predicted performance up...
With a temperature of $\sim 285$ K WISE0855 is the coldest brown dwarf observed so far. Using James Webb Space Telescope (JWST) we obtained observations that allow us to characterize WISE0855s atmosphere focusing on vertical variation in water steam abundance, measuring trace gas abundances and receiving bulk parameters for this cold object. We ultra cool using Mid-Infrared Instrument Medium Resolution Spectrometer (MIRI/MRS) onboard JWST at spectral resolution up 3750. combined observation...
Retrieving the physical parameters from spectroscopic observations of exoplanets is key to understanding their atmospheric properties. Exoplanetary retrievals are usually based on approximate Bayesian inference and rely sampling-based approaches compute parameter posterior distributions. Accurate or repeated retrievals, however, can result in very long computation times due sequential nature algorithms. We aim amortize exoplanetary retrieval using neural estimation (NPE), a simulation-based...
Abstract Exoplanetary systems show a wide variety of architectures, which can be explained by different formation and dynamical evolution processes. Precise orbital monitoring is mandatory to accurately constrain their parameters. Although major observational theoretical advances have been made in understanding the architecture properties exoplanetary systems, many outstanding questions remain. This paper aims give brief review few current challenges studies future prospects for improving...
We present a set of recommended best practices for JWST data collection members the community focussed on direct imaging and spectroscopy exoplanetary systems. These findings recommendations are based early analysis Early Release Science Program 1386, "High-Contrast Imaging Exoplanets Exoplanetary Systems with JWST." Our goal is this information to be useful observers in preparation proposals Cycle 2 beyond. In addition compiling from our ERS program, few cases we also draw expertise gained...