Observations of Comet 9P/Tempel 1 around the Deep Impact event by the OSIRIS cameras onboard Rosetta
2007 (English)In: Icarus (New York, N.Y. 1962), ISSN 0019-1035, Vol. 187, no 1, 87-103 p.Article in journal (Refereed) Published
The OSIRIS cameras on the Rosetta spacecraft observed Comet 9P/Tempel 1 from 5 days before to 10 days after it was hit by the Deep Impactprojectile. The Narrow Angle Camera (NAC) monitored the cometary dust in 5 different filters. The Wide Angle Camera (WAC) observed through filters sensitive to emissions from OH, CN, Na, and OI together with the associated continuum. Before and after the impact the comet showedregular variations in intensity. The period of the brightness changes is consistent with the rotation period of Tempel 1. The overall brightness ofTempel 1 decreased by about 10% during the OSIRIS observations. The analysis of the impact ejecta shows that no new permanent coma structureswere created by the impact. Most of the material moved with ∼200 m s−1 . Much of it left the comet in the form of icy grains which sublimatedand fragmented within the first hour after the impact. The light curve of the comet after the impact and the amount of material leaving the comet(4.5–9 × 106 kg of water ice and a presumably larger amount of dust) suggest that the impact ejecta were quickly accelerated by collisions withgas molecules. Therefore, the motion of the bulk of the ejecta cannot be described by ballistic trajectories, and the validity of determinations ofthe density and tensile strength of the nucleus of Tempel 1 with models using ballistic ejection of particles is uncertain.
Place, publisher, year, edition, pages
2007. Vol. 187, no 1, 87-103 p.
Comet Tempel-1; Comets, coma; Impact processes
IdentifiersURN: urn:nbn:se:uu:diva-14975DOI: 10.1016/j.icarus.2006.09.023OAI: oai:DiVA.org:uu-14975DiVA: diva2:42746