A5054768565- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Adaptive optics and wavefront sensing
- Scientific Research and Discoveries
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Spacecraft Dynamics and Control
- China's Socioeconomic Reforms and Governance
- Hong Kong and Taiwan Politics
- Chinese history and philosophy
- Planetary Science and Exploration
Goddard Space Flight Center
2019-2024
University of Maryland, Baltimore County
2024
National Postdoctoral Association
2022
University of Idaho
2014-2019
Abstract We carry out a phase-curve analysis of the KELT-9 system using photometric observations from NASA’s Transiting Exoplanet Survey Satellite (TESS). The measured secondary eclipse depth and peak-to-peak atmospheric brightness modulation are <?CDATA ${650}_{-15}^{+14}$?> 566 ± 16 ppm, respectively. planet’s variation reaches maximum 31 5 minutes before midpoint eclipse, indicating 5.°2 0.°9 eastward shift in dayside hot spot substellar point. also detect stellar pulsations on with...
Abstract A critically important process affecting the climate evolution and potential habitability of an exoplanet is atmospheric escape, in which high-energy radiation from a star drives escape hydrogen atoms other light elements planet’s atmosphere. L 98-59 benchmark system for studying such processes, with three transiting terrestrial-sized planets receiving Venus-like instellations (4–25 S ⊕ ) their M3 host star. We use VPLanet model to simulate its inner small planets, given different...
We constrain the true spin–orbit alignment of KOI-89 system by numerically fitting two Kepler photometric light curves produced transiting planets KOI-89.01 and KOI-89.02. The have periods 84.69 207.58 days, respectively. find that bodies are low-density giant with radii 0.45 ± 0.03 Rjup 0.43 0.05 misalignments 72° 3° , Through dynamic stability tests, we demonstrate general trend higher close to mutual estimate their coalignment angle 20° 20°—i.e., misaligned star but may be aligned each...
We report the discovery of an ultrahot Jupiter with extremely short orbital period $0.67247414\,\pm\,0.00000028$ days ($\sim$16 hr). The $1.347 \pm 0.047$ $R_{\rm Jup}$ planet, initially identified by Transiting Exoplanet Survey Satellite (TESS) mission, orbits TOI-2109 (TIC 392476080): a $T_{\rm eff} \sim 6500$ K F-type star mass $1.447 0.077$ $M_{\rm Sun}$, radius $1.698 0.060$ and rotational velocity $v\sin i_* = 81.9 1.7$ km s$^{-1}$. planetary nature TOI-2109b was confirmed through...
We present an optical-to-infrared transmission spectrum of the inflated sub-Saturn KELT-11b measured with Transiting Exoplanet Survey Satellite (TESS), Hubble Space Telescope (HST) Wide Field Camera 3 G141 spectroscopic grism, and Spitzer (Spitzer) at 3.6 $\mu$m, in addition to a 4.5 $\mu$m secondary eclipse. The precise HST notably reveals low-amplitude water feature unusual shape. Based on free retrieval analyses varying molecular abundances, we find strong evidence for absorption....
Abstract MASCARA-4 b is a hot Jupiter in highly misaligned orbit around rapidly rotating A3V star that was observed for 54 days by the Transiting Exoplanet Survey Satellite ( TESS ). We perform two analyses of using stellar gravity-darkened model. First, we measure b’s orbital configuration modeling its photometric light curve. take advantage asymmetry transit due to host star’s surface true spin–orbit angle be 104° <?CDATA ${}_{-{13}^{^\circ }}^{+{7}^{^\circ }}$?> . also detect ∼4 σ...
We fit the \emph{Kepler} photometric light curve of KOI-368 system using an oblate, gravity-darkened stellar model in order to constrain its spin-orbit alignment. find that is relatively well-aligned with a sky-projected alignment $\lambda=10^{\circ}\pm2^{\circ}$, obliquity $\psi=3^{\circ}\pm7^{\circ}$, and true $\varphi=11^{\circ}\pm3^{\circ}$. Although our measurement differs significantly from zero, low value for $\varphi$ consistent also measure various transit parameters system:...
The Transiting Exoplanet Survey Satellite (TESS) has detected thousands of exoplanet candidates since 2018, most which have yet to be confirmed. A key step in the confirmation process these is ruling out false positives through vetting. Vetting also eases burden on follow-up observations, provides input for demographics studies, and facilitates training machine learning algorithms. Here we present TESS Triple-9 (TT9) catalog -- a uniformly-vetted containing dispositions 999 listed...
KELT-9 b is an ultra hot Jupiter transiting a rapidly rotating, oblate early-A-type star in polar orbit. We model the effect of rapid stellar rotation on b's transit light curve using photometry from Transiting Exoplanet Survey Satellite (\tess) to constrain planet's true spin-orbit angle and explore how may be influenced by gravity darkening. host star's equatorial radius $1.089\pm0.017$ times as large its local surface brightness vary $\sim38$\% between poles cooler equator. oblateness...
Abstract We investigate how rapid stellar rotation commonly seen in A/F stars can influence planet habitability. Specifically, we model influences a planet’s irradiation and determine the location of habitable zone for mass range 1.3 M ⊙ ≤ ⋆ 2.2 . Rapid dramatically change star’s luminosity spectral energy distribution, therefore affect habitability any surrounding planets. Stars ≳ rotate near their breakup speeds, which causes two effects relevant to First, these flatten into oblate...
Abstract We measure the bulk system parameters of seismically active, rapidly rotating δ -Scuti KOI-976 and constrain orbit geometry its transiting binary companion using a combined approach asteroseismology gravity-darkening light curve analysis. is 1.62 ± 0.2 M ⊙ star with measured v sin( i ) 120 2 km s −1 induced variable signal that varies by ∼0.6% star’s total photometric brightness. take advantage oblate shape seismic activity to perform three measurements obliquity angle relative...
I model the effect of rapid stellar rotation on a planet's insolation. Fast-rotating stars have induced pole-to-equator temperature gradients (known as gravity-darkening) up to several thousand Kelvin that affect star's luminosity and peak emission wavelength function latitude. When orbiting such star, annual insolation can strongly vary depending its orbit inclination. Specifically, inclined orbits result in temporary exposure hotter poles. find gravity-darkening drive changes equilibrium...
Abstract NASA’s TESS mission yields light curves for tens of millions stars spread across the entire sky, a data set that will be challenge to fully exploit without help from citizen scientists. To address this, we launched new science project, called “Planet Patrol”, designed analyze on exoplanet and eclipsing binary candidates. The project also serve benchmark different reduction pipelines unusual might defeat automated algorithms. first stage ran Zooniverse platform between 2020 September...
Abstract High-resolution transmission spectroscopy is a powerful method for probing the extended atmospheres of short-period exoplanets. With advancement ultrastable echelle spectrographs and advent 30 m class telescopes on horizon, even minor observational physical effects will become important when modeling atmospheric absorption atomic species. In this work we demonstrate how nonuniform temperature across surface fast rotating star, i.e., gravity darkening, can affect observed spectrum in...
We constrain the true spin-orbit alignment of KOI-89 system by numerically fitting two \emph{Kepler} photometric lightcurves produced transiting planets KOI-89.01 and KOI-89.02. The have periods 84.69 days 207.58 days, respectively. find that bodies are low-density giant with radii $0.45 \pm 0.03~\mathrm{R_{jup}}$ $0.43 0.05~\mathrm{R_{jup}}$ misalignments $72^{\circ} 3^\circ$ $73^{\circ+11}_{-5}$, Via dynamic stability tests we demonstrate general trend higher close to mutual estimate their...
Research Article| November 21 1945 Shanghai at the War's End John Ahlers Search for other works by this author on: This Site PubMed Google Scholar Far Eastern Survey (1945) 14 (23): 329–333. https://doi.org/10.2307/3023153 Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Facebook Twitter LinkedIn Email Tools Get Permissions Cite Citation Ahlers; End. 1945; doi: Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers...
A critically important process affecting the climate evolution and potential habitability of an exoplanet is atmospheric escape, in which high-energy radiation from a star drives escape hydrogen atoms other light elements planet's atmosphere. L 98-59 benchmark system for studying such processes, with three transiting terrestrial-size planets receiving Venus-like instellations (4-25 S$_\oplus$) their M3 host star. We use VPLanet model to simulate its inner small planets, given different...
Abstract We analyze Kepler photometry of transiting planet candidate KOI-972.01, accounting for both stellar variability and gravity darkening. KOI-972.01 stands out because its small radius, less than that Neptune, intermediate orbit period at 13.12 days, long enough to avoid significant tidal evolution, thus it represents an underexplored exoplanet class. The parent star is a rapidly rotating δ -Scuti variable, complicating transit lightcurve interpretation but also offering potential...