39 citations · 125 across the 22 of their papers we have counts for
23 papers
Validating the SCALES DRP: A Performance Study of the Medium-Resolution IFS Mode
Athira Unni, Steph Sallum, Max Brodheim +11
We present a performance verification of the medium-resolution integral field spectrograph (IFS) mode of the SCALES Data Reduction Pipeline (SCALES-DRP) using data obtained during…
Pre-shipment optical characterization of the SCALES instrument
Isabel J. Kain, Reni Kupke, Daren Dillon +31
The Slicer Combined with an Array of Lenslets for Exoplanet Spectroscopy (SCALES) instrument is a 1-5 micron imager and 2-5 micron integral field spectrograph, currently being comm…
An Observational Study of Systematics in Differential Transmission Spectroscopy Using HFOSC on the Himalayan Chandra Telescope
Manjunath Bestha, Athira Unni, T Sivarani +2
Ground-based low-resolution transmission spectroscopy requires photometric precision of a few hundred parts per million, making it sensitive to instrumental and atmospheric systema…
A new broadband atmospheric dispersion corrector for HROS-TMT
Manjunath Bestha, Thirupathi Sivarani, Bachar Wehbe +7
Atmospheric dispersion causes light from celestial objects with different wavelengths to refract at varying angles as it passes through Earth's atmosphere. This effect results in a…
Addressing wavelength-correlated systematics in exoplanet transmission spectroscopy: a 2D Gaussian Process approach
Lokesh Manickavasaham, Manjunath Bestha, Sivarani Thirupathi +2
Ground-based transmission spectroscopy is often dominated by systematics, which obstructs our ability to leverage the advantages of larger aperture sizes compared to space-based ob…
Atmospheric Dispersion Measurement at Hanle Site
Manjunath Bestha, Sivarani Thirupathi, Athira Unni +2
Atmospheric dispersion introduces wavelength-dependent effects that significantly impact ground-based observations, particularly in slit- and fibre-fed spectroscopic studies. These…
A multi-object approach for studying exoplanet atmospheres using high-resolution spectrographs
Manjunath Bestha, Athira Unni, T. Sivarani +5
Atmospheric characterization of exoplanets has traditionally relied on Low-Resolution Transmission Spectroscopy (LRTS), obtained from both space- and ground-based facilities, as we…
An Initial Assessment of the Hanle Echelle Spectrograph for Exoplanet Atmosphere Studies
Manjunath Bestha, Athira Unni, T. Sivarani +6
Transmission spectroscopy is an effective technique for probing exoplanetary atmospheres. While most observations have relied on space facilities such as HST and JWST, ground-based…
SCALES-DRP : A Data Reduction Pipeline for an Upcoming Keck Thermal Infrared Spectrograph
Athira Unni, Steph Sallum, Peyton Benac +5
We present the end-to-end data reduction pipeline for SCALES (Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy), the upcoming thermal-infrared, diffraction-limited…
Volcanic Satellites Tidally Venting Na, K, SO2 in Optical & Infrared Light
Apurva V. Oza, Andrea Gebek, Moritz Meyer zu Westram +19
Recent infrared spectroscopy from the James Webb Space Telescope (JWST) has spurred analyses of common volcanic gases such as carbon dioxide (CO2), sulfur dioxide (SO2), alongside…
Doppler Shifted Transient Sodium Detection by KECK/HIRES
Athira Unni, Apurva V. Oza, H. Jens Hoeijmakers +12
We carried out the first high-resolution transit observations of the exoplanet WASP-49 Ab with Keck/HIRES. Upon custom wavelength calibration we achieve a Doppler RV precision of $…
Low-resolution Transit Spectroscopy of Three Hot Jupiters Using the 2m Himalayan Chandra Telescope
Athira Unni, Thirupathi Sivarani, Jayesh Goyal +3
Here, we present the low-resolution transmission spectroscopy of three giant planets using the Himalayan Faint Object Spectrograph Camera (HFOSC) on the 2m Himalayan Chandra Telesc…
Redshifted Sodium Transient near Exoplanet Transit
Apurva V. Oza, Julia V. Seidel, H. Jens Hoeijmakers +21
Neutral sodium (Na I) is an alkali metal with a favorable absorption cross section such that tenuous gases are easily illuminated at select transiting exoplanet systems. We examine…
A multi-functional fiber positioning system for Extremely Large Telescopes
Manjunath Bestha, T. Sivarani, Arun Surya +7
We present a conceptual design for a fiber positioning system for multi-object high-resolution spectroscopy, designed to be compatible with the upcoming large telescopes with a wid…
Age analysis of extrasolar planets: Insight from stellar isochrone models
C. Swastik, Ravinder K. Banyal, Mayank Narang +2
There is growing evidence from stellar kinematics and galactic chemical evolution (GCE) suggesting that giant planets (M0.3) are relatively young compared to the m…
Optical spectroscopy of comets using Hanle Echelle Spectrograph (HESP)
K Aravind, Kumar Venkataramani, Shashikiran Ganesh +5
Observing the vibrational/rotational lines in a comet's optical spectrum requires high-resolution spectroscopy, as they are otherwise seen as a blended feature. To achieve this, we…
The Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy (SCALES): driving science cases and expected outcomes
Steph Sallum, Andrew Skemer, Deno Stelter +34
The Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy (SCALES) is a m, high-contrast integral field spectrograph (IFS) currently being built for Keck Observa…
Age distribution of exoplanet host stars: Chemical and Kinematics age proxies from GAIA DR3
C. Swastik, Ravinder K. Banyal, Mayank Narang +4
The GAIA space mission is impacting astronomy in many significant ways by providing a uniform, homogeneous and precise data set for over 1 billion stars and other celestial objects…
Carbon abundance of stars in the LAMOST-Kepler field
Athira Unni, Mayank Narang, Thirupathi Sivarani +5
The correlation between host star iron abundance and the exoplanet occurrence rate is well-established and arrived at in several studies. Similar correlations may be present for th…
Galactic chemical evolution of exoplanet host stars: Are high-mass planetary systems young?
C. Swastik, Ravinder K. Banyal, Mayank Narang +5
The imprints of stellar nucleosynthesis and chemical evolution of the galaxy can be seen in different stellar populations, with older generation stars showing higher -element ab…
The TESS-Keck Survey. VIII. Confirmation of a Transiting Giant Planet on an Eccentric 261 day Orbit with the Automated Planet Finder Telescope
Paul A. Dalba, Stephen R. Kane, Diana Dragomir +72
We report the discovery of TOI-2180 b, a 2.8 giant planet orbiting a slightly evolved G5 host star. This planet transited only once in Cycle 2 of the primary Transiting…
Optical and NIR spectroscopy of cool CEMP stars to probe the nucleosynthesis in low mass AGB binary system
A. Susmitha, D. K. Ojha, T. Sivarani +4
We present the abundance analyses of 7 Carbon enhanced metal-poor (CEMP) stars to understand the origin of carbon in them. We used high-resolution optical spectra to derive abundan…
Activity of the first interstellar comet 2I/Borisov around perihelion: Results from Indian observatories
Aravind Krishnakumar, Shashikiran Ganesh, Kumar Venkataramani +4
Comet 2I/Borisov is the first true interstellar comet discovered. Here we present results from observational programs at two Indian observatories, 2 m Himalayan Chandra Telescope a…