The Herschel-SPIRE submillimetre spectrum of Mars
Abstract
We have obtained the first continuous disk averaged spectrum of Mars from 450 to 1550 Ghz using the Herschel-SPIRE Fourier Transform Spectrometer. The spectrum was obtained at a constant resolution of 1.4 GHz across the whole band. The flux from the planet is such that the instrument was operated in "bright source" mode to prevent saturation of the detectors. This was the first successful use of this mode and in this work we describe the method used for observing Mars together with a detailed discussion of the data reduction techniques required to calibrate the spectrum. We discuss the calibration accuracy obtained and describe the first comparison with surface and atmospheric models. In addition to a direct photometric measurement of the planet the spectrum contains the characteristic transitions of 12CO from J 5-4 to J 13-12 as well as numerous H2O transitions. Together these allow the comparison to global atmospheric models allowing the mean mixing ratios of water and 12CO to be investigated. We find that it is possible to match the observed depth of the absorption features in the spectrum with a fixed water mixing ratio of 1 x 10-4 and a 12CO mixing ratio of 9 x 10-4
Keywords
Cite
@article{arxiv.1005.4579,
title = {The Herschel-SPIRE submillimetre spectrum of Mars},
author = {B. M. Swinyard and P. Hartogh and S. Sidher and T. Fulton and E. Lellouch and C. Jarchow and M. J. Griffin and R. Moreno and H. Sagawa and G. Portyankina and M. Blecka and M. Banaszkiewicz and D. Bockelee-Morvan and J. Crovisier and T. Encrenaz and M. Kueppers and L. Lara and D. Lis and A. Medvedev and M. Renge and S. Szutowicz and B. Vandenbussche and F. Bensch and E. Bergin and F. Billebaud and N. Biver and G. Blake and J. Blommaert and M. de Val-Borro and J. Cernicharo and T. Cavalie and R. Courtin and G. Davis and L. Decin and P. Encrenaz and T. de Graauw and E. Jehin and M. Kidger and S. Leeks and G. Orton and D. Naylor and R. Schieder and D. Stam and N. Thomas and E. Verdugo and C. Waelkens and H. Walker},
journal= {arXiv preprint arXiv:1005.4579},
year = {2015}
}
Comments
Accepted for publication in Astronomy&Astrophysics, Herschel First Results special issue