An Initial Assessment of the Hanle Echelle Spectrograph for Exoplanet Atmosphere Studies

Fuente: arXiv
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Main Authors: Bestha, Manjunath, Unni, Athira, Sivarani, T., Menon, Shivangi, M, Parvathy, Surya, Arun, Saraf, Pallavi, Divakar, Devika, Manickavasaham, Lokesh
Format: Preprint
Published: 2025
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author Bestha, Manjunath
Unni, Athira
Sivarani, T.
Menon, Shivangi
M, Parvathy
Surya, Arun
Saraf, Pallavi
Divakar, Devika
Manickavasaham, Lokesh
author_facet Bestha, Manjunath
Unni, Athira
Sivarani, T.
Menon, Shivangi
M, Parvathy
Surya, Arun
Saraf, Pallavi
Divakar, Devika
Manickavasaham, Lokesh
contents 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 high-resolution transmission spectroscopy (HRTS) has also provided valuable insights by resolving individual atomic features. In this work, we present an initial performance assessment and feasibility test of the Hanle Echelle Spectrograph (HESP) on the 2 m Himalayan Chandra Telescope (HCT) for HRTS. As a benchmark, we observed the hot Jupiter HD 209458b during a single transit at a resolution of R = 30,000. We developed a Python-based, semi-automated data reduction and analysis pipeline that includes corrections for telluric contamination and stellar radial velocity shifts. The final achieved signal-to-noise ratio and spectral stability allow us to probe for features at the 0.1% level. This work establishes a methodology and demonstrates the operational capability of the HESP-HCT for obtaining high-resolution transmission spectra.
format Preprint
id arxiv_https___arxiv_org_abs_2509_17142
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle An Initial Assessment of the Hanle Echelle Spectrograph for Exoplanet Atmosphere Studies
Bestha, Manjunath
Unni, Athira
Sivarani, T.
Menon, Shivangi
M, Parvathy
Surya, Arun
Saraf, Pallavi
Divakar, Devika
Manickavasaham, Lokesh
Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
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 high-resolution transmission spectroscopy (HRTS) has also provided valuable insights by resolving individual atomic features. In this work, we present an initial performance assessment and feasibility test of the Hanle Echelle Spectrograph (HESP) on the 2 m Himalayan Chandra Telescope (HCT) for HRTS. As a benchmark, we observed the hot Jupiter HD 209458b during a single transit at a resolution of R = 30,000. We developed a Python-based, semi-automated data reduction and analysis pipeline that includes corrections for telluric contamination and stellar radial velocity shifts. The final achieved signal-to-noise ratio and spectral stability allow us to probe for features at the 0.1% level. This work establishes a methodology and demonstrates the operational capability of the HESP-HCT for obtaining high-resolution transmission spectra.
title An Initial Assessment of the Hanle Echelle Spectrograph for Exoplanet Atmosphere Studies
topic Earth and Planetary Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2509.17142