Using near-infrared spectroscopy for characterization of transiting exoplanets

Observational Astronomy, Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden
e-mail: erik.aronson@physics.uu.se

Received: 24 April 2014
Accepted: 27 March 2015

Abstract

Context. We propose a method for observing transiting exoplanets with near-infrared high-resolution spectrometers.

Aims. We aim to create a robust data analysis method for recovering atmospheric transmission spectra from transiting exoplanets over a wide wavelength range in the near-infrared.

Methods. By using an inverse method approach, combined with stellar models and telluric transmission spectra, the method recovers the transiting exoplanet’s atmospheric transmittance at high precision over a wide wavelength range. We describe our method and have tested it by simulating observations.

Results. This method is capable of recovering transmission spectra of high enough accuracy to identify absorption features from molecules such as O₂, CH₄, CO₂, and H₂O. This accuracy is achievable for Jupiter-size exoplanets at S/N that can be reached for 8 m class telescopes using high-resolution spectrometers (R> 20 000) during a single transit, and for Earth-size planets and super-Earths transiting late K or M dwarf stars at S/N reachable during observations of less than 10 transits. We also analyse potential error sources to show the robustness of the method.

Conclusions. Detection and characterization of atmospheres of both Jupiter-size planets and smaller rocky planets looks promising using this set-up.