A5024353797- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Galaxies: Formation, Evolution, Phenomena
- Markov Chains and Monte Carlo Methods
- Scientific Research and Discoveries
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
Pennsylvania State University
2018-2020
United States Naval Observatory
2010-2013
The third US Naval Observatory (USNO) CCD Astrograph Catalog, UCAC3 was released at the IAU General Assembly on 2009 August 10. It is first all-sky release in this series and contains just over 100 million objects, about 95 of them with proper motions, covering R = 8 to 16 magnitudes. Current epoch positions are obtained from observations 20 cm aperture USNO Astrograph's "red lens", equipped a 4k by CCD. Proper motions derived combining these 140 ground- space-based catalogs, including...
Abstract We characterize the occurrence rate of planets, ranging in size from 0.5 to 16 R ⊕ , orbiting FGK stars with orbital periods 500 days. Our analysis is based on results “DR25” catalog planet candidates produced by NASA’s Kepler mission and stellar radii Gaia “DR2.” incorporate additional data products accurately efficiency planets being recognized as “threshold crossing events” ’s Transiting Planet Search pipeline labeled robovetter. Using a hierarchical Bayesian model, we derive...
We present robust planet occurrence rates for Kepler candidates around M stars radii $R_p = 0.5-4~\textrm{R}_\oplus$ and orbital periods $P 0.5-256$ days using the approximate Bayesian computation (ABC) technique. This work incorporates final DR25 candidate catalog data products augments them with updated stellar properties Gaia DR2 2MASS PSC. apply a set of selection criteria to select sample 1,746 dwarf targets that host 89 associated candidates. These early dwarfs late K were selected...
We present a new framework to characterize the occurrence rates of planet candidates identified by Kepler based on hierarchical Bayesian modeling, Approximate Computing (ABC), and sequential importance sampling. For this study we adopt simple 2-D grid in radius orbital period as our model apply algorithm estimate for Q1-Q16 orbiting around solar-type stars. arrive at significantly increased small ($R_p<1.25 R_{\oplus}$) larger periods ($P>80$d) compared estimated more common inverse...
The newly completed Fourth USNO CCD Astrographic Catalog (UCAC4) has proven to be a rich source of double star astrometry and photometry. Following initial comparisons UCAC4 results against those obtained by speckle interferometry, the catalog was matched known stars in Washington Double Star order provide additional differential photometry for these pairs. Matches 58,131 pairs yielded 61,895 astrometric 68,935 photometric measurements. Finally, search possible new common proper motion (CPM)...
We infer the number of planets-per-star as a function orbital period and planet size using $Kepler$ archival data products with updated stellar properties from $Gaia$ Data Release 2. Using hierarchical Bayesian modeling Hamiltonian Monte Carlo, we incorporate radius uncertainties into an inhomogeneous Poisson point process model. demonstrate that this model captures general features outcome formation evolution around GK stars, provides infrastructure to use results constrain analytic...