Arjun B. Savel
A5003268458- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Isotope Analysis in Ecology
- Astronomical Observations and Instrumentation
- Scientific Research and Discoveries
- Spacecraft and Cryogenic Technologies
- High-pressure geophysics and materials
- Space Exploration and Technology
- Planetary Science and Exploration
- Calibration and Measurement Techniques
- Geological and Geochemical Analysis
- Spectroscopy and Laser Applications
- Atmospheric Ozone and Climate
- Solar and Space Plasma Dynamics
- Parallel Computing and Optimization Techniques
- SAS software applications and methods
- Species Distribution and Climate Change
- Adaptive optics and wavefront sensing
- Marine animal studies overview
- Methane Hydrates and Related Phenomena
- Cardiovascular Disease and Adiposity
University of Maryland, College Park
2020-2024
Simons Foundation
2022-2024
Flatiron Health (United States)
2023-2024
Flatiron Institute
2023-2024
University of California, Berkeley
2020-2022
Foreman-Mackey et al., (2021). exoplanet: Gradient-based probabilistic inference for exoplanet data & other astronomical time series. Journal of Open Source Software, 6(62), 3285, https://doi.org/10.21105/joss.03285
Abstract Close-in giant exoplanets with temperatures greater than 2,000 K (‘ultra-hot Jupiters’) have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from Hubble Space Telescope (HST) and Spitzer 1–3 . However, previous studies yielded inconsistent results because small sizes spectral features limited information content data resulted in high sensitivity varying assumptions made treatment instrument systematics retrieval...
High-resolution spectra are unique indicators of three-dimensional processes in exoplanetary atmospheres. For instance, 2020, Ehrenreich et al. reported transmission from the ESPRESSO spectrograph yielding an anomalously large Doppler blueshift ultra-hot Jupiter WASP-76b. Interpretations these observations invoke toy model depictions gas-phase iron condensation lower-temperature regions planet's atmosphere. In this work, we forward atmosphere WASP-76b with double-gray general circulation...
Abstract The near-infrared transmission spectrum of the warm sub-Neptune exoplanet GJ 1214 b has been observed to be flat and featureless, implying a high metallicity atmosphere with abundant aerosols. Recent JWST MIRI Low Resolution Spectrometer observations phase curve showed that its is out into mid-infrared. In this paper, we use combined near- mid-infrared constrain atmospheric composition aerosol properties. We generate grid photochemical haze models using an microphysics code for...
Abstract The atmospheric dynamics of tidally locked hot Jupiters is characterized by strong equatorial winds. Understanding the interaction between global circulation and chemistry crucial in studies interpreting observations. Two-dimensional (2D) photochemical transport models shed light on how composition depends circulation. In this paper, we introduce 2D (horizontal vertical) model, VULCAN 2D, which improves pseudo-2D approaches allowing for nonuniform zonal We extensively validate our...
Abstract The large radii of many hot Jupiters can only be matched by models that have interior adiabats, and recent theoretical work has shown the evolution a significant impact on their atmospheric structure. Due to its inflated radius, low gravity, ultrahot equilibrium temperature, WASP-76b is an ideal case study for internal observable properties. Hot interiors should most strongly affect nonirradiated side planet, thus full phase-curve observations are critical ascertain effect...
ABSTRACT Exoplanet atmospheres are inherently three-dimensional systems in which thermal/chemical variation and winds can strongly influence spectra. Recently, the ultra-hot Jupiter WASP-76 b has shown evidence for condensation asymmetric Fe absorption with time. However, it is currently unclear whether these asymmetries driven by chemical or thermal differences between two limbs, as precise constraints on have remained elusive due to challenges of modelling dynamics a Bayesian framework. To...
Abstract Ultrahot Jupiters are ideal candidates to explore with high-resolution emission spectra. Detailed theoretical studies necessary investigate the range of spectra that we can expect see from these objects throughout their orbit, because extreme temperature and chemical longitudinal gradients exist across dayside nightside regions. Using previously published 3D general circulation models WASP-76b different treatments magnetic drag, postprocess atmospheres generate for two wavelength...
Abstract The Transiting Exoplanet Survey Satellite (TESS) has discovered hundreds of new worlds, with TESS planet candidates now outnumbering the total number confirmed planets from Kepler. Owing to differences in survey design, continues provide that are better suited for subsequent follow-up studies, including mass measurement through radial velocity (RV) observations, compared Kepler targets. In this work, we present TESS-Keck Survey’s (TKS) Mass Catalog: a uniform analysis all TKS RV...
Abstract Due to their likely tidally synchronized nature, (ultra)hot Jupiter atmospheres should experience strongly spatially heterogeneous instellation. The large irradiation contrast and resulting atmospheric circulation induce temperature chemical gradients that can produce asymmetries across the eastern western limbs of these during transit. By observing an Jupiter’s transmission spectrum at high spectral resolution, be recovered—namely through net Doppler shifts originating from...
Abstract Inhomogeneous cloud formation and wavelength-dependent phenomena are expected to shape hot Jupiter atmospheres. We present a general circulation model with multiwavelength “picket fence” radiative transfer radiatively active, temperature-dependent clouds, compare the results those of double gray routine. The method inherently fails polychromatic effects in atmospheres, while picket fence captures these non-gray aspects performs well compared fully methods. both methods active clouds...
Abstract Sub-Neptunes—volatile-rich exoplanets smaller than Neptune—are intrinsically the most common type of planet known. However, formation and nature these objects, as well distinctions between subclasses (if any), remain unclear. Two powerful tools to tease out secrets worlds are measurements (i) atmospheric composition structure revealed by transit and/or eclipse spectroscopy, (ii) mass, radius, density photometry Doppler spectroscopy. Here, we present OrCAS, a survey better elucidate...
Abstract Measuring the abundances of carbon- and oxygen-bearing molecules has been a primary focus in studying atmospheres hot Jupiters, as doing so can help constrain carbon-to-oxygen (C/O) ratio. The C/O ratio reveal evolution formation pathways Jupiters provide strong understanding atmospheric composition. In last decade, high-resolution spectral analyses have become increasingly useful measuring precise several molecules. This allows for more constraint We present four transits Jupiter...
Abstract Ground-based high-resolution cross-correlation spectroscopy (HRCCS; R ≳ 15,000) is a powerful complement to space-based studies of exoplanet atmospheres. By resolving individual spectral lines, HRCCS can precisely measure chemical abundance ratios, directly constrain atmospheric dynamics, and robustly probe multidimensional physics. But the subtleties data sets—e.g., lack exoplanetary spectra visible by eye statistically complex process telluric removal—can make interpreting them...
TOI-2015 is a known exoplanetary system around an M4 dwarf star, consisting of transiting sub-Neptune planet in 3.35-day orbital period, TOI-2015,b, accompanied by non-transiting companion, TOI-2015,c. High-precision radial-velocity measurements were taken with the spectrograph, and high-precision photometric data collected, primarily using SPECULOOS, MUSCAT, TRAPPIST LCOGT networks. We collected 63 transit light curves 49 different epochs for TOI-2015,b. re-characterized target star...
Abstract The sub-Neptune GJ 1214 b has an infamously flat transmission spectrum, likely due to thick aerosols in its atmosphere. A recent JWST/MIRI spectroscopic phase curve of added this picture, suggesting a highly reflective and metal-rich Using 3D general circulation model with both photochemical hazes condensate clouds, we characterize how different aerosol types affect the atmospheric structure manifest curve. Additionally, reanalyze original JWST reanalysis shows hotter nightside,...
One core goal of the Kepler mission was to determine frequency Earth-like planets that orbit Sun-like stars. Accurately estimating this planet occurrence rate requires both a well-vetted list and clear understanding stars searched for planets. Previous ground-based follow-up observations have, through variety methods, sought improve our knowledge are known host targets without detected planets, however, have not been subjected same intensity observations. In paper, we better constrain...
Studies of close-in planets orbiting M dwarfs have suggested that the dwarf radius valley may be well-explained by distinct formation timescales between enveloped terrestrials, and rocky form at late times in a gas-depleted environment. This scenario is odds with picture primordial gaseous envelope subsequently stripped away some thermally-driven mass loss process. These two physical scenarios make unique predictions rocky/enveloped transition's dependence on orbital separation such studying...
The public, all-sky surveys Gaia and TESS provide the ability to identify new young associations determine their ages. These enable study of planetary evolution by providing opportunities discover exoplanets. A association was recently identified Tang et al. F{\"u}rnkranz using astrometry from (called "Group-X" former). In this work, we investigate age membership association; validate exoplanet TOI 2048 b, which transit a young, late G dwarf in Group-X photometry TESS. We first candidate...
Abstract High-resolution spectroscopy has allowed for unprecedented levels of atmospheric characterization, especially the hottest gas-giant exoplanets known as ultrahot Jupiters (UHJs). spectra are sensitive to 3D effects, making complex models important interpreting data. Moreover, these planets expected host magnetic fields that will shape their resulting circulation patterns, but little modeling work been done investigate effects. In this paper, we generate high-resolution transmission...
We analysed 68 candidate planetary systems first identified during Campaigns 5 and 6 (C5 C6) of the NASA \textit{K2} mission. set out to validate these by using a suite follow-up observations, including adaptive optics, speckle imaging, reconnaissance spectroscopy. The overlap between C5 with C16 C18, C6 C17, yields lightcurves long baselines that allow us measure transit ephemeris very precisely, revisit single candidates in earlier campaigns, search for additional transiting planets longer...
The James Webb Space Telescope (JWST) will be able to probe the atmospheres and surface properties of hot, terrestrial planets via emission spectroscopy. We identify 18 potentially planet candidates detected by Transiting Exoplanet Survey Satellite (TESS) that would make ideal targets for these observations. These cover a broad range radii ($R_{\rm p} \sim 0.6 - 2.0 R_\oplus$) orbit stars various magnitudes ($K_s = 5.78 10.78$, $V 8.4 15.69$) effective temperatures ($T_{\rm eff }\sim 3000...