Deep Impact Observations by OSIRIS Onboard the Rosetta Spacecraft
Horst Uwe Keller,1*
Laurent Jorda,2
Michael Küppers,1
Pedro J. Gutierrez,3
Stubbe F. Hviid,1
Jörg Knollenberg,4
Luisa-Maria Lara,3
Holger Sierks,1
Cesare Barbieri,5
Philippe Lamy,2
Hans Rickman,6
Rafael Rodrigo3
The OSIRIS cameras (optical, spectroscopic, and infrared remote
imaging system) onboard the European Space Agency's Rosetta
spacecraft observed comet 9P/Tempel 1 for 17 days continuously
around the time of NASA's Deep Impact mission. The cyanide-to-water
production ratio was slightly enhanced in the impact cloud,
compared with that of normal comet activity. Dust particles
were flowing outward in the coma at >160 meters per second,
accelerated by the gas. The slope of the brightness increase
showed a dip about 200 seconds after the impact. Dust Af
values
before and long after the impact confirm the slight decrease
of cometary activity. The dust-to-water mass ratio was much
larger than 1.
2 Laboratoire d'Astrophysique de Marseille, Boite Postal 8, 13376 Marseille Cedex, France.
3 Instituto de Astrofísica de Andalucía–Consejo Superior de Investigaciones Científicas, C/Camino Bajo de Huétor, 50, 18008 Granada, Spain.
4 Deutsches Zentrum für Luft- und Raumfahrt, Institut für Planetenforschung, Rutherfordstrasse 2, 12489 Berlin, Germany.
5 Dipartimento di Astronomia e Centro Interdipartimentale Studi ed Attività Spaziali "G. Colombo," Università di Padova, Vicolo dell'Osservatorio 5, 35100 Padova, Italy.
6 Uppsala Astronomical Observatory, Box 515, 75120 Uppsala, Sweden.
* To whom correspondence should be addressed. E-mail: keller{at}mps.mpg.de
