Spectroscopic Observations of Comet C/2013 A1 (Siding Spring) from Mars using ChemCam, OMEGA and SPICAM.

Thursday, 18 December 2014: 11:20 AM
Jeremie Lasue1, Brigitte Gondet2, Jean-Loup Bertaux3, Bruce Lee Barraclough4, Pierre Beck5, Stephen Bender4, Jean-Pierre Bibring6, Nathan Thomas Bridges7, Jean-Yves Chaufray8, Olivier Gasnault9, Kenneth E Herkenhoff10, Yves Langevin6, Stephane Le Mouelic2, Mark T Lemmon11, Eric Lewin5, Timothy H McConnochie12, Javier Martín-Torres13, Sylvestre Maurice1, Pierre-Yves Meslin14, Douglas W Ming15, Franck Montmessin16, Tobias C Owen17, William Rapin9, Francis Rocard18, Roger C Wiens19 and Maria-Paz Zorzano20, (1)IRAP, Toulouse, France, (2)CNRS, Paris Cedex 16, France, (3)University of Versailles Saint-Quentin en Yvelines, Versailles, France, (4)Planetary Science Institute Los Alamos, Los Alamos, NM, United States, (5)University Joseph Fourier Grenoble, Grenboble, France, (6)IAS Institut d'Astrophysique Spatiale, Orsay Cedex, France, (7)Applied Physics Laboratory Johns Hopkins, Laurel, MD, United States, (8)LATMOS Laboratoire Atmosphères, Milieux, Observations Spatiales, Guyancourt, France, (9)Universite de Toulouse, Toulouse Cedex 4, France, (10)USGS Astrogeology Science Center, Flagstaff, AZ, United States, (11)Texas A & M University, College Station, TX, United States, (12)University of Maryland College Park, College Park, MD, United States, (13)Instituto Andaluz de Ciencias de la Tierra, Granada, Spain, (14)Universite Paul Sabatier, Toulouse, France, (15)NASA Johnson Space Center, Houston, TX, United States, (16)Service d'aéronomie du CNRS, Verrieres Le Buisson, France, (17)Univ Hawaii, Honolulu, HI, United States, (18)CNES French National Center for Space Studies, Toulouse Cedex 09, France, (19)Space Science and Applications, Los Alamos, NM, United States, (20)INTA-CSIC, Madrid, Spain
Comet Siding Spring will graze Mars on Oct. 19th 2014. Its closest approach from the centre of the planet will be 135,000 km, and its predicted visual magnitude as low as -5.3 (JPL Horizons web site). The observing conditions will be ideal to attempt spectroscopic measurements of the inner coma from the UV to the IR at an unprecedented spectral resolution from the instruments located on and around Mars.
ChemCam is a Laser-Induced Breakdown Spectroscopy instrument operating on-board the Mars Science Laboratory rover to analyse the chemical composition of rocks and can be used for passive spectroscopy. ChemCam is equipped with high resolution spectrometers covering the optical range (240–850 nm) with a pixel resolution of 0.05nm up to 470nm and 0.2nm in the near-IR range. The ChemCam passive spectroscopy field of view is 0.65 mrad wide and covers several 100km projected on the coma. Based on predicted magnitude and inner coma intensity variations, we expect to retrieve spectral signatures around the nucleus. Simultaneously the 7 instruments on board Mars Express will take measurements in nadir and limb modes. We will merge the results obtained with ChemCam with those of the 2 imaging spectrometers SPICAM (110-310 nm resolution of 0.6nm and 1-1.7 µm resolution of 1.5 nm) and OMEGA (457-910 nm resolution of 1.5 nm and 2.5-5.1 µm resolution of 15 nm) to obtain the composition and spatial variation of emitting molecules in the different parts of the coma. The instruments will also monitor the atmosphere before and after the encounter to detect any change.
We will report on the preparations for the observations and the spectroscopy results, with emphasis on the detection of complex organic molecules and the spatial distribution of H2O and OH in the inner coma. A decision will be made on the adequacy of risk reduction activities for the spacecraft, and planned science operations may need to be cancelled by ESOC.
This work is supported by NASA, ESA and CNES.