The rotation state of 67P/Churyumov-Gerasimenko from approach observations with the OSIRIS cameras on Rosetta
S. Mottola
(1)
,
S. Lowry
(2)
,
C. Snodgrass
(3)
,
P. L. Lamy
(4)
,
I. Toth
(5)
,
A. Rożek
(2)
,
H. Sierks
(3)
,
Michael F. A'Hearn
(6)
,
F. Angrilli
(7)
,
C. Barbieri
(7)
,
M. A. Barucci
(8, 9)
,
Jean-Loup Bertaux
(10)
,
Gabriele Cremonese
(11)
,
V. da Deppo
(12)
,
B. Davidsson
(13)
,
M. de Cecco
(14)
,
S. Debei
(15)
,
S. Fornasier
(8)
,
M. Fulle
(16)
,
O. Groussin
(4)
,
Pedro J. Gutiérrez
(17)
,
S. F. Hviid
(1)
,
W. Ip
(18)
,
L. Jorda
(4)
,
H. U. Keller
(19)
,
J. Knollenberg
(1)
,
D. Koschny
(20)
,
R. Kramm
(3)
,
Ekkehard Kührt
(1)
,
M. Küppers
(21)
,
L. Lara
(17)
,
M. Lazzarin
(7)
,
J. J. Lopez Moreno
(17)
,
F. Marzari
(22)
,
H. Michalik
,
G. Naletto
(23)
,
H. Rickman
(13)
,
R. Rodrigo
(24, 25)
,
L. Sabau
(26)
,
N. Thomas
(27)
,
K.-P. Wenzel
(20)
,
J. Agarwal
(3)
,
I. Bertini
(12)
,
F. Ferri
(12)
,
C. Güttler
(3)
,
S. Magrin
(6)
,
N. Oklay
(3)
,
C. Tubiana
(3)
,
J.-B. Vincent
(3)
1
DLR Institute of Planetary Research
2 CAPS - Centre for Astrophysics and Planetary Science [Canterbury]
3 MPS - Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research
4 LAM - Laboratoire d'Astrophysique de Marseille
5 Konkoly Observatory
6 Department of Astronomy [College Park]
7 Dipartimento di Fisica e Astronomia "Galileo Galilei"
8 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
9 OP - Observatoire de Paris - Site de Paris
10 PLANETO - LATMOS
11 OAPD - INAF - Osservatorio Astronomico di Padova
12 CISAS - Centro di Ateneo di Studi e Attività Spaziali “Giuseppe Colombo”
13 Department of Physics and Astronomy [Uppsala]
14 UNITN - Università degli Studi di Trento = University of Trento
15 Department of Industrial Engineering [Padova]
16 OAT - INAF - Osservatorio Astronomico di Trieste
17 IAA - Instituto de Astrofísica de Andalucía
18 Institute of Space Science [Taiwan]
19 Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig]
20 RSSD - Research and Scientific Support Department, ESTEC
21 ESAC - European Space Astronomy Centre
22 Dipartimento di Fisica [Padova]
23 DEI - Department of Information Engineering [Padova]
24 CAB - Centro de Astrobiologia [Madrid]
25 ISSI - International Space Science Institute [Bern]
26 INTA - Instituto Nacional de Técnica Aeroespacial
27 Physikalisches Institut [Bern]
2 CAPS - Centre for Astrophysics and Planetary Science [Canterbury]
3 MPS - Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research
4 LAM - Laboratoire d'Astrophysique de Marseille
5 Konkoly Observatory
6 Department of Astronomy [College Park]
7 Dipartimento di Fisica e Astronomia "Galileo Galilei"
8 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
9 OP - Observatoire de Paris - Site de Paris
10 PLANETO - LATMOS
11 OAPD - INAF - Osservatorio Astronomico di Padova
12 CISAS - Centro di Ateneo di Studi e Attività Spaziali “Giuseppe Colombo”
13 Department of Physics and Astronomy [Uppsala]
14 UNITN - Università degli Studi di Trento = University of Trento
15 Department of Industrial Engineering [Padova]
16 OAT - INAF - Osservatorio Astronomico di Trieste
17 IAA - Instituto de Astrofísica de Andalucía
18 Institute of Space Science [Taiwan]
19 Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig]
20 RSSD - Research and Scientific Support Department, ESTEC
21 ESAC - European Space Astronomy Centre
22 Dipartimento di Fisica [Padova]
23 DEI - Department of Information Engineering [Padova]
24 CAB - Centro de Astrobiologia [Madrid]
25 ISSI - International Space Science Institute [Bern]
26 INTA - Instituto Nacional de Técnica Aeroespacial
27 Physikalisches Institut [Bern]
L. Jorda
- Fonction : Auteur
- PersonId : 746464
- IdHAL : laurent-jorda
- ORCID : 0000-0001-8735-3308
- IdRef : 180975161
H. Michalik
- Fonction : Auteur
Résumé
Aims: Approach observations with the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) experiment onboard Rosetta are used to determine the rotation period, the direction of the spin axis, and the state of rotation of comet 67P's nucleus. Methods: Photometric time series of 67P have been acquired by OSIRIS since the post wake-up commissioning of the payload in March 2014. Fourier analysis and convex shape inversion methods have been applied to the Rosetta data as well to the available ground-based observations. Results: Evidence is found that the rotation rate of 67P has significantly changed near the time of its 2009 perihelion passage, probably due to sublimation-induced torque. We find that the sidereal rotation periods P1 = 12.76129 ± 0.00005 h and P2 = 12.4043 ± 0.0007 h for the apparitions before and after the 2009 perihelion, respectively, provide the best fit to the observations. No signs of multiple periodicity are found in the light curves down to the noise level, which implies that the comet is presently in a simple rotation state around its axis of largest moment of inertia. We derive a prograde rotation model with spin vector J2000 ecliptic coordinates λ = 65° ± 15°, β = + 59° ± 15°, corresponding to equatorial coordinates RA = 22°, Dec = + 76°. However, we find that the mirror solution, also prograde, at λ = 275° ± 15°, β = + 50° ± 15° (or RA = 274°, Dec = + 27°), is also possible at the same confidence level, due to the intrinsic ambiguity of the photometric problem for observations performed close to the ecliptic plane. Table 1 is available in electronic form at http://www.aanda.org
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