A5082043486- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Molecular Spectroscopy and Structure
- High-pressure geophysics and materials
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Mass Spectrometry Techniques and Applications
- Spectroscopy and Laser Applications
- Geological and Geochemical Analysis
- SAS software applications and methods
- Space Exploration and Technology
- Pulsars and Gravitational Waves Research
- Particle Accelerators and Free-Electron Lasers
- earthquake and tectonic studies
- Astrophysical Phenomena and Observations
Clemson University
2021-2024
Missouri State University
2016-2018
Abstract We present an overview and first results from a M -band spectroscopic survey of planet-forming disks performed with iSHELL on the Infrared Telescope Facility, using two slits that provide resolving power R ≈ 60,000–92,000 (5–3.3 km s −1 ). provides nearly complete coverage at 4.52–5.24 μ m in one shot, covering >50 lines P branches 12 CO 13 for each multiple vibrational levels, providing unprecedented information excitation emission absorption components. Some most notable new...
We report on time-series photometric observations in the earliest stages of superoutbursts extreme dwarf novae, AL Com and WZ Sge, which started 2001 May after 6 years quiescence July 23 quiescence, respectively. detected growth "early superhumps" during each rising stage. Our reject mass transfer instability for trigger superoutburst Sge stars, show existence some relations between spiral structure, gives a hint origin superhumps."
Abstract We present high-resolution spectra and spectroastrometric (SA) measurements of fundamental rovibrational CO emission from nine nearby (≲300 pc) protoplanetary disks where large inner dust cavities have been observed. The emission-line profiles SA signals are fit with a slab disk model that allows the eccentricity intensity to vary as power laws. Six sources well our model, three these show asymmetric line can be by adopting nonzero eccentricity. other components in either their...
Abstract CI Tau is currently the only T Tauri star with an inner protoplanetary disk that hosts a planet, b, has been detected by radial velocity survey. This provides unique opportunity to study features were imprinted planet. We present multiepoch spectroscopic data, taken NASA IRTF in 2022, of 12 CO and hydrogen Pf β line emissions spanning nine consecutive nights, which proposed orbital period b. find star’s accretion rate varied according nine-day period, indicative companion-driven...
We report a new subdwarf B pulsator, PG 1142-037, discovered during the first full-length campaign of K2, two-gyro mission Kepler space telescope. 14 periodicities have been detected between 0.9 and 2.5 hr with amplitudes below 0.35 parts-per-thousand. able to associate all pulsations low-degree, ℓ ≤ 2 modes. Follow-up spectroscopy 1142 has revealed it be in binary period 0.54 d. Phase-folding K2 photometry reveals two-component variation including both Doppler boosting ellipsoidal...
The Kepler spacecraft observed ∼150 000 stars over the course of its four-year mission, which 18 were discovered to be pulsating subdwarf B stars, including KIC 2697388. We analyse three years short-cadence data as well 21 low-resolution spectra star Our have a radial-velocity scatter 9.5 km s−1, and while insufficient completely rule out binarity, we short-period, low-inclination orbits for From data, detect 253 periodicities, most with periods from 1 2.5 h, associate gravity-mode...
We analyse the full Kepler short cadence data set of pulsating subdwarf B star KIC 11558725. 11558725 is in an sdB+WD binary system with a period 10.05 d and known to be subsynchronously rotating. From set, we detected 245 pulsation frequencies, mostly gravity (g-) mode region, but some pressure (p-) region as well. are able identify 142 these pulsations ℓ ≤ 2 modes 27 = 6 modes. Frequency splittings g- p-mode regions indicate that solid-body rotator rotation ∼44 d. The multiplets do not...
Movement of the earth's axis rotation relative to crust earth will be retarded if polymorphic transitions occur in upper mantle earth. For static equilibrium such transitions, or phase changes, at an equipotential ellipsoidal surface whose symmetry coincides with rotation. cause asymmetric distribution material that is not equilibrium, since are self-inhibited by their release absorption heat. This asymmtric could balance any mass (such as continents and oceans) might tend polar wandering....
We report results of our analysis the Kepler superaperture LC data open cluster NGC6791 to search for pulsating sdB stars. checked all pixels and we found only three stars be pulsating, KIC2569576 (B3), KIC2438324 (B4) KIC2437937 (B5). These were known pulsators before, though extended coverage detecting more frequencies features in their amplitude spectra, i.e. new multiplets complete period spacing sequences that used identifying geometry pulsation modes. The multiplet splittings also...
CI Tau is currently the only T Tauri star with an inner protoplanetary disk that hosts a planet, b, has been detected by radial velocity survey. This provides unique opportunity to study features were imprinted planet. We present multi-epoch spectroscopic data, taken NASA IRTF in 2022, of ${}^{12}$CO and hydrogen Pf$β$ line emissions spanning 9 consecutive nights, which proposed orbital period b. find star's accretion rate varied according 9~d period, indicative companion driven accretion....
We present high-resolution spectra and spectroastrometric (SA) measurements of fundamental rovibrational CO emission from nine nearby ($\lesssim$300 pc) protoplanetary disks where large inner dust cavities have been observed. The line profiles SA signals are fit with a slab disk model that allows the eccentricity intensity to vary as power laws. Six sources well our model, three these show asymmetric can be by adopting non-zero eccentricity. other components in either their profile or signal...