Berlin 2014 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 5: Postersitzung

EP 5.10: Poster

Tuesday, March 18, 2014, 16:30–18:30, DO24 Foyer

SUMER observations of sungrazing comet 2012/S1 during perihelion — •Werner Curdt, Hermann Böhnhardt, Sami Solanki, Luca Teriaca, and Udo Schühle — Max Planck Institute for Solar System Research; Katlenburg-Lindau, Germany

During its recent perihelion passage comet ISON came so close to the Sun that it appeared in the field-of-view of the SUMER spectrometer on SOHO and allowed observations with high spatial and temporal resolution. We report results of spectroscopic observations of the comet during its encounter with the Sun. Our data show the dust tail behind the predicted position of the nucleus in Lyman-alpha emission, seen as light from the solar disk scattered at fine dust particles. The tail is offset from the trajectory and not aligned with it. We model the dust emission and dynamic to reproduce the appearance of the tail. We could not find any signature of activity around the expected position of the nucleus and conclude that the outgassing processes must have stopped before the comet entered our FOV. After observing 18 years mostly solar targets, this was the first time that SUMER completed spectroscopic observations of a comet.