High-Resolution Echelle Spectroscopy for Solar System Planets: A Planet-as-Point-Source Analogy

Abstract

Transmission spectroscopy has proven to be an effective technique for characterizing exoplanet atmospheres. However, transmission spectroscopy requires planetary transits, which occur for only a small fraction of planetary systems due to geometric alignment constraints; hence, characterizing exoplanets through their reflected spectrum of host stars will be helpful for a large number of exoplanets. The upcoming extremely large telescopes (ELTs) will be able to study the reflected spectra of exoplanets. Here, we present a preliminary optical design and a detailed throughput analysis of the instrumentation that interfaces the 2.34 m Vainu Bappu Telescope prime focus to an existing high-resolution echelle spectrograph with disk-integrated light from solar system objects. One of the primary objectives is to obtain high-resolution, high signal-to-noise reflected spectra from the solar system objects.