Author(s): , , , , ,
Institution(s): 1. ACRI-st, 2. Finnish Meteorological Institute, 3. LATMOS/IPSI, Université de Versailles Saint-Quentin, 4. University of Michigan
The all-sky hydrogen Lyman-alpha camera, SWAN (Solar Wind Anisotropies), on the SOlar and Heliospheric Observatory (SOHO) satellite makes observations of the hydrogen coma of comets. Most water vapor produced by comets is ultimately photodissociated into two H atoms and one O atom producing a huge atomic hydrogen coma that is routinely observed in the daily full-sky SWAN images in comets of sufficient brightness. Water production rates are calculated using our time-resolved model (Mäkinen & Combi, 2005, Icarus 177, 217), typically yielding about 1 observation every 2 days on the average. Here we describe the progress in analysis of observations of comets observed during 2014-2015 and those selected from the archive for analysis. These include comets C/2012 K1 (PanSTARRS), C/2013 V5, (Oukaimeden), C/2014 Q2 (Lovejoy) and 15P/Finlay. A status report on the entire SOHO/SWAN archive of water production rates in comets will also be given. SOHO is an international cooperative mission between ESA and NASA. Support from grants NNX11AH50G from the NASA Planetary Astronomy Program and NNX13AQ66G from the NASA Planetary Mission Data Analysis Program are gratefully acknowledged as is support from CNRS, CNES, and the Finnish Meteorological Institute (FMI).