Observations of Comet 9P/Tempel 1 around the Deep Impact event by the OSIRIS cameras onboard Rosetta
Horst Uwe Keller
(1)
,
Michael Küppers
(1)
,
Sonia Fornasier
(2, 3, 4)
,
Pedro J. Gutierrez
(5)
,
Stubbe F. Hviid
(1)
,
Laurent Jorda
(6)
,
Jörg Knollenberg
(7)
,
Stephen Lowry
(8)
,
Miriam Rengel
(1)
,
Ivano Bertini
(4)
,
Gabriele Cremonese
(9)
,
W. Ip
(10)
,
Detlef Koschny
(11)
,
Rainer Kramm
(1)
,
Ekkehard Kührt
(7)
,
Luisa M. Lara
(5)
,
Holger Sierks
(1)
,
Nicholas Thomas
(12)
,
Cesare Barbieri
(4)
,
Philippe Lamy
(6)
,
Hans Rickman
(13)
,
Rafael Rodrigo
(5)
,
M. F. A'Hearn
(14)
,
Francesco Angrilli
(15, 16)
,
Maria Antonella Barucci
(2, 3)
,
Jean-Loup Bertaux
(17)
,
Vania da Deppo
(18)
,
Björn Davidsson
(13)
,
M. de Cecco
(19)
,
Stefano Debei
(19)
,
Marco Fulle
(20)
,
Fritz Gliem
(21)
,
Olivier Groussin
(14)
,
José J. López-Moreno
(5)
,
Francesco Marzari
(22)
,
Giampiero Naletto
(18)
,
Lola Sabau
(23)
,
Angel Sanz Andrés
(24)
,
Klaus-Peter Wenzel
(11)
1
MPS -
Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research
2 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
3 Pôle Planétologie du LESIA
4 CISAS - Centro di Ateneo di Studi e Attività Spaziali “Giuseppe Colombo”
5 IAA - Instituto de Astrofísica de Andalucía
6 LAM - Laboratoire d'Astrophysique de Marseille
7 DLR Institut für Planetenforschung
8 ARC - Astrophysics Research Centre [Belfast]
9 OAPD - INAF - Osservatorio Astronomico di Padova
10 Institute of Space Science [Taiwan]
11 ESTEC - European Space Research and Technology Centre
12 Physikalisches Institut [Bern]
13 Department of Astronomy and Space Physics [Uppsala]
14 Department of Astronomy [College Park]
15 Unipd - Università degli Studi di Padova = University of Padua
16 Dipartimento di Ingegneria Meccanica [Padova]
17 SA - Service d'aéronomie
18 DEI - Department of Information Engineering [Padova]
19 UNITN - Università degli Studi di Trento = University of Trento
20 OAT - INAF - Osservatorio Astronomico di Trieste
21 Institut für Datentechnik und Kommunikationsnetze
22 Dipartimento di Fisica e Astronomia "Galileo Galilei"
23 INTA - Instituto Nacional de Técnica Aeroespacial
24 Instituto de Microgravedad "Ignacio Da Riva"
2 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
3 Pôle Planétologie du LESIA
4 CISAS - Centro di Ateneo di Studi e Attività Spaziali “Giuseppe Colombo”
5 IAA - Instituto de Astrofísica de Andalucía
6 LAM - Laboratoire d'Astrophysique de Marseille
7 DLR Institut für Planetenforschung
8 ARC - Astrophysics Research Centre [Belfast]
9 OAPD - INAF - Osservatorio Astronomico di Padova
10 Institute of Space Science [Taiwan]
11 ESTEC - European Space Research and Technology Centre
12 Physikalisches Institut [Bern]
13 Department of Astronomy and Space Physics [Uppsala]
14 Department of Astronomy [College Park]
15 Unipd - Università degli Studi di Padova = University of Padua
16 Dipartimento di Ingegneria Meccanica [Padova]
17 SA - Service d'aéronomie
18 DEI - Department of Information Engineering [Padova]
19 UNITN - Università degli Studi di Trento = University of Trento
20 OAT - INAF - Osservatorio Astronomico di Trieste
21 Institut für Datentechnik und Kommunikationsnetze
22 Dipartimento di Fisica e Astronomia "Galileo Galilei"
23 INTA - Instituto Nacional de Técnica Aeroespacial
24 Instituto de Microgravedad "Ignacio Da Riva"
Résumé
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 Impact projectile. 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 showed regular variations in intensity. The period of the brightness changes is consistent with the rotation period of Tempel 1. The overall brightness of Tempel 1 decreased by about 10% during the OSIRIS observations. The analysis of the impact ejecta shows that no new permanent coma structures were created by the impact. Most of the material moved with ˜200ms. Much of it left the comet in the form of icy grains which sublimated and 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 9×10kg of water ice and a presumably larger amount of dust) suggest that the impact ejecta were quickly accelerated by collisions with gas molecules. Therefore, the motion of the bulk of the ejecta cannot be described by ballistic trajectories, and the validity of determinations of the density and tensile strength of the nucleus of Tempel 1 with models using ballistic ejection of particles is uncertain.