EChO spectra and stellar activity II. The case of dM stars

Abstract

EChO is a dedicated mission to investigate exoplanetary atmospheres. When extracting the planetary signal, one has to take care of the variability of the hosting star, which introduces spectral distortion that can be mistaken as planetary signal. Magnetic variability is a major deal in particular for M stars. To this purpose, assuming a one spot dominant model for the stellar photosphere, we develop a mixed observational-theoretical tool to extract the spot's parameters from the observed optical spectrum. This method relies on a robust library of spectral M templates, which we derive using the observed spectra of quiet M dwarfs in the SDSS database. Our procedure allows to correct the observed spectra for photospheric activity in most of the analyzed cases, reducing the spectral distortion down to the noise levels. Ongoing refinements of the template library and the algorithm will improve the efficiency of our algorithm.

Submitted to Experimental Astronomy

References in corpus (3)

• Low-Mass Dwarf Template Spectra from the Sloan Digital Sky Survey
• Fluxes in Hαand Ca II H and K for a sample of Southern stars
• X-Shooter spectroscopy of young stellar objects III. Photospheric and chromospheric properties of Class III objects

Cited by in corpus (6)

• Large Binocular Telescope view of the atmosphere of GJ1214b
• Phase curve pollution of exoplanet transmission spectra
• Correcting the effect of stellar spots on ARIEL transmission spectra
• The widest broadband transmission spectrum (0.38-1.71 $\mu$m) of HD 189733b from ground-based chromatic Rossiter-McLaughlin observations
• Stellar activity consequence on the retrieved transmission spectra through chromatic Rossiter-McLaughlin observations
• A reanalysis of the LHS 1140 b atmosphere observed with the Hubble Space Telescope