Reliable elimination of telluric lines from stellar spectra

¹ Astronomical Institute of the Charles University, V Holešovičkách 2, 180 00 Praha 8, Czech Republic e-mail: mary@atrey.karlin.mff.cuni.cz
² Astronomical Institute, Academy of Sciences, 251 65 Ondřejov, Czech Republic

Received: 24 January 2005
Accepted: 27 February 2005

Abstract

We demonstrate that the powerful disentangling technique used to separate the individual spectra of binary components and telluric lines can also be used to remove telluric lines from the spectrum of a single star by treating the telluric spectrum as a second star. We tested that on the spectra of α Boo (=Arcturus) secured with a Reticon detector in the coudé focus of the Ondřejov 2-m telescope. We demonstrate that the method works well and is invaluable especially for the spectra of red stars which are heavily blended with the telluric lines. The disadvantage of the method is that one needs a number of spectra of the star in question, secured at different months of the year. The advantage is that one obtains the final disentangled stellar spectrum with a high  ratio.