Automatic model-based telluric correction for the ESPRESSO data reduction software

Context. Ground-based high-resolution spectrographs are key instruments for several astrophysical domains, such as exoplanet studies. Unfortunately, the observed spectra contaminated by Earth’s atmosphere and its large molecular absorption bands. While different techniques (forward radiative transfer models, principle component analysis (PCA), or other empirical methods) exist to correct telluric lines in atmospheric studies, radial velocity (RV) with an depth of >2% generally masked, which poses a problem faint targets M dwarfs most their RV content is present where contamination important. Aims. We propose simple model be embedded Echelle SPectrograph Rocky Exoplanets Stable Spectroscopic Observations (ESPRESSO) data reduction software (DRS). The goal provide telluric-free enable measurements through cross-correlation function technique (and others), including spectral ranges fall. Methods. line-by-line code that assumes single layer. use sky conditions physical properties from HITRAN database create spectrum. This then convolved instrumental resolution sampled wavelength grid. A subset selected used robustly fit spectrum Levenberg-Marquardt minimization algorithm. Results. computed H 2 O range ESPRESSO. When applied stellar A0- M5-type stars, residuals strongest water below 2% peak-to-valley (P2V) amplitude all types, exception dwarfs, within pseudo-continuum. determined RVs telluric-corrected ESPRESSO Tau Ceti Proxima. created masks compared obtained DRS RVs. In case Ceti, we identified micro-telluric introduce systematics up 58 cm s −1 period one year if not corrected. For Proxima, impact negligible due low flux 5900 A. late-type gain at redder wavelengths equivalent 25% photon noise factor 1.78 exposure time. leads better constraints on semi-amplitude eccentricity Proxima d, was recently proposed planet candidate. Finally, our γ -band P2V amplitude. Conclusions. individual achieve precise removal lines, coupled range, more Moreover, showcase can molecules, thus regions spectrographs, NIRPS.