A5030720210- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Adaptive optics and wavefront sensing
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Planetary Science and Exploration
- Force Microscopy Techniques and Applications
- Mechanics and Biomechanics Studies
- Space Exploration and Technology
- Gamma-ray bursts and supernovae
- Near-Field Optical Microscopy
- Particle Accelerators and Free-Electron Lasers
- Atmospheric Ozone and Climate
- Laser-induced spectroscopy and plasma
- Astronomical and nuclear sciences
- High-pressure geophysics and materials
- Atmospheric and Environmental Gas Dynamics
- Gas Dynamics and Kinetic Theory
- Advanced X-ray Imaging Techniques
- Surface Roughness and Optical Measurements
Physical Research Laboratory
2018-2023
University of Arkansas at Little Rock
2002
United States Air Force Research Laboratory
1982
Context . Being the most numerous and oldest stars in galaxy, M dwarfs are objects of great interest for exoplanet searches. The presence molecules their atmosphere complicates our understanding atmospheric properties. But advances have recently been made modeling due to revision solar abundances. Aims We aim determine stellar parameters using high resolution spectra ( R ∼ 90 000) simultaneously visible near-infrared. broad wavelength coverage provide an unique opportunity understand onset...
We present the discovery and characterization of a sub-Saturn exoplanet, TOI-6038~A~b, using PARAS-2 spectrograph. The planet orbits bright ($m_V=9.9$), metal-rich late F-type star, TOI-6038~A, with $T_{\rm{eff}}=6110\pm100~\mathrm{K}$, $\log{g}=4.118^{+0.015}_{-0.025}$, $[{\rm{Fe/H}}]=0.124^{+0.079}_{-0.077}$ dex. system also contains wide-orbit binary companion, TOI-6038~B, an early K-type star at projected separation $\approx3217$ AU. combined radial velocity data from photometric...
Abstract We present the discovery and characterization of a sub-Saturn exoplanet, TOI-6038 A b, using PARAS-2 spectrograph. The planet orbits bright ( m V = 9.9), metal-rich late F-type star, A, with T eff 6110 ± 100 K, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>log</mml:mi> <mml:mi>g</mml:mi> <mml:mo>=</mml:mo> <mml:mn>4.11</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>8</mml:mn> </mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.025</mml:mn> <mml:mo>+</mml:mo>...
We report the discovery of an intermediate-mass transiting brown dwarf, TOI-503b, from TESS mission. TOI-503b is first dwarf discovered by and orbits a metallic-line A-type star with period $P=3.6772 \pm 0.0001$ days. The light curve indicates that transits its host in grazing manner, which limits precision we measure dwarf's radius ($R_b = 1.34^{+0.26}_{-0.15} R_J$). obtained high-resolution spectroscopic observations FIES, Ondřejov, PARAS, Tautenburg, TRES spectrographs measured mass to be...
We present here the information on design and performance of recently commissioned 2.5-meter telescope at PRL Mount Abu Observatory, located Gurushikhar, Abu, India. The has been successfully installed site, Site Acceptance Test (SAT) was completed in October 2022. It is a highly advanced India, featuring Ritchey-Chrétien optical configuration with primary mirror active optics, tip-tilt sideport, wave front correction sensors. Along telescope, its two first light instruments namely Faint...
We report the discovery and characterization of a transiting sub-Saturn exoplanet TOI-6651b using PARAS-2 spectroscopic observations. The host, TOI-6651 ($m_{V}\approx 10.2$), is sub-giant, metal-rich G-type star with $[{\rm Fe/H}] = 0.225^{+0.044}_{-0.045}$, $T_{\rm eff} 5940\pm110\ \mathrm{K}$, $\log{g} 4.087^{+0.035}_{-0.032}$. Joint fitting radial velocities from spectrograph transit photometric data Transiting Exoplanet Survey Satellite (TESS) reveals planetary mass $61.0^{+7.6}_{-7.9}\...
We report here strong evidence for a sub-Saturn around EPIC~211945201 and confirm its planetary nature. EPIC~211945201b was found to be candidate from {\it K2} photometry in Campaigns 5 \& 16, transiting bright star ($V_{\rm mag}=10.15$, G0 spectral type) 19.492 day orbit. However, the photometric data combined with false positive probability calculations using VESPA not sufficient scenario. Here we present high-resolution spectroscopic follow-up of target PARAS spectrograph (19 radial...
Eclipsing Binaries (EBs) with one of the companions as very low mass stars (VLMS or M dwarfs) are testbeds to substantiate stellar models and evolutionary theories. Here, we present four EB candidates F type primaries, namely, SAO 106989, HD 24465, EPIC 211682657 205403, identified from different photometry missions, SuperWasp, KELT, Kepler 2 (K2) STEREO. Using high-resolution spectrograph, PARAS, at 1.2 m telescope Mount Abu, Rajasthan, India, hereby report detection VLMS EBs. We performed...
We present the discovery of a transiting massive giant planet around TOI-4603, sub-giant F-type star from NASA’s Transiting Exoplanet Survey Satellite (TESS). The newly discovered has radius 1.042 −0.035 +0.038 R J and an orbital period 7.24599 −0.00021 +0.00022 days. Using radial velocity measurements with PARAS TRES spectrographs, we determined planet’s mass to be 12.89 −0.57 +0.58 M , resulting in bulk density 14.1 −1.6 +1.7 g cm −3 . This makes it one few known planets extreme density....
We report here the discovery of a hot Jupiter at an orbital period $3.208666\pm0.000016$ days around TOI-1789 (TYC 1962-00303-1, $TESS_{mag}$ = 9.1) based on TESS photometry, ground-based and high-precision radial velocity observations. The observations were obtained from high-resolution spectrographs, PARAS Physical Research Laboratory (PRL), India, TCES Th\"uringer Landessternwarte Tautenburg (TLS), Germany, transit using 0.43~m telescope PRL with Bessel-$R$ filter. host star is slightly...
We present here the optical and mechanical design of a fiber-fed High-resolution spectrograph at resolution (R) = 100,000 which will be under vacuum (0.001 to 0.005 mbar) temperature controlled environment 25C ± 0.001C. The attached our upcoming new PRL 2.5m aperture telescope Gurushikar, Mount Abu, Rajasthan, India. is named PARAS-2 after successful operation PARAS (PARAS-1) with existing 1.2m Abu since 2012 summer. (PARAS-2) operating in range 380nm 690nm wavelength single shot using Grism...
We present here the information on design and performance of recently commissioned 2.5-meter telescope at PRL Mount Abu Observatory, located Gurushikhar, Abu, India. The has been successfully installed site, Site Acceptance Test (SAT) was completed in October 2022. It is a highly advanced India, featuring Ritchey-Chr$\acute{e}$tien optical configuration with primary mirror active optics, tip-tilt side-port, wave front correction sensors. Along telescope, its two first light instruments...
The Rapid Burster is a unique neutron star low-mass X-ray binary system, showing both thermonuclear Type-I and accretion-driven Type-II bursts. Recent studies have demonstrated how coordinated observations of radio variability can constrain jet properties accreting stars - particularly when the dominated by discrete changes. We present simultaneous VLA, Swift, INTEGRAL observing campaign to investigate whether its responds observe counterpart at faintest-detected luminosity, while reveal...
We present here the precise wavelength calibration of a high-resolution spectrum using Uranium (U) lines in range 3809 - 6833 \AA\ for precision radial velocity measurements exoplanet detection or related astrophysical sciences. identify 1540 well-resolved U from (R=67,000) uranium-argon hollow cathode lamp (UAr HCL) PARAS spectrograph aforesaid range. calculate neutral and first allowed transitions (Ritz wavelength) its known energy levels compare them with our observed central wavelengths....
Atmospheric emission measured at 2.7 µm by the SPIRE earth limb rocket experiment under sunlit conditions has not been fully understood to date. While initial analysis showed this be different from hydroxyl spectra observed on night side during same experiment, authors were only able speculate processes responsible. In paper, we develop a model of fluorescent CO2 hot band explain approximately 40% data. addition, include results two other models show contributions required and H20 resonant...
A novel method for mapping the surface profile of electrostatically deposited powder is reported. The employs deposition charged, monodispersed fluorescent latex spheres (FLS) with 2.26 /spl mu/m diameter on before and after deposition. substrates layer mapped by imaging FLS an epifluorescent microscope a resolution plusmn/2 in z-axis plusmn/5 x- y-axes. Typically, 1 cm/spl times/1 cm area scanned at mm intervals. profiles are plotted using Origin 6 software 3D presentation. also applied to...
We present the discovery of a transiting massive giant planet around TOI-4603, sub-giant F-type star from NASA's Transiting Exoplanet Survey Satellite (TESS). The newly discovered has radius $1.042^{+0.038}_{-0.035}$ $R_{J}$, and an orbital period $7.24599^{+0.00022}_{-0.00021}$ days. Using radial velocity measurements with PARAS {and TRES} spectrographs, we determined planet's mass to be $12.89^{+0.58}_{-0.57}$ $M_{J}$, resulting in bulk density $14.1^{+1.7}_{-1.6}$ g ${cm^{-3}}$. This...