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Journal Articles Astronomy and Astrophysics - A&A Year : 2016

Possible interpretation of the precession of comet 67P/Churyumov-Gerasimenko

1 IAA - Instituto de Astrofísica de Andalucía
2 LAM - Laboratoire d'Astrophysique de Marseille
3 PSI - Planetary Science Institute [Tucson]
4 Department of Physics and Astronomy [Uppsala]
5 DLR Institute of Planetary Research
6 IGEP - Institut für Geophysik und Extraterrestrische Physik [Braunschweig]
7 IMCCE - Institut de Mécanique Céleste et de Calcul des Ephémérides
8 CAB - Centro de Astrobiologia [Madrid]
9 ESAC - European Space Astronomy Centre
10 ISSI - International Space Science Institute [Bern]
11 MPS - Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research
12 Dipartimento di Fisica e Astronomia "Galileo Galilei"
13 ESTEC - European Space Research and Technology Centre
14 CBK - Space Research Centre of Polish Academy of Sciences
15 Department of Astronomy [College Park]
16 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
17 PLANETO - LATMOS
18 CISAS - Centro di Ateneo di Studi e Attività Spaziali “Giuseppe Colombo”
19 OAPD - INAF - Osservatorio Astronomico di Padova
20 IFN - CNR Institute for Photonics and Nanotechnologies
21 Department of Industrial Engineering [Padova]
22 UNITN - Università degli Studi di Trento = University of Trento
23 Physikalisches Institut [Bern]
24 OAT - INAF - Osservatorio Astronomico di Trieste
25 IANCU - Institute of Astronomy [Taiwan]
26 Operations Department (ESAC)
27 SSERVI - Solar System Exploration Research Virtual Institute
28 DEI - Department of Information Engineering [Padova]
29 INTA - Instituto Nacional de Técnica Aeroespacial
30 CSH - Center for Space and Habitability
Pedro J. Gutiérrez
  • Function : Author
  • PersonId : 880386
L. Jorda
Jean-Loup Bertaux
  • Function : Author
  • PersonId : 914210

Abstract

Data derived from the reconstruction of the nucleus shape of comet 67P/Churyumov-Gerasimenko (67P) from images of the OSIRIS camera onboard ROSETTA show evidence that the nucleus rotates in complex mode. First, the orientation of the spin axis is not fixed in an inertial reference frame, which suggests a precessing motion around the angular momentum vector with a periodicity of approximately 257 h ± 12 h.Second, periodograms of the right ascension and declination (RA/Dec) coordinates of the body-frame Z axis show a very significant (higher than 99.99%) periodicity at 276 h ± 12 h, different from the rotational period of 12.40 h as previously determined from light-curve analysis. Aims. The main goal is to interpret the data and associated periodicities of the spin axis orientation in space. Methods. We analyzed the spin axis orientation in space and associated periodicities and compared them with solutions of Euler equations under the assumption that the body rotates in torque-free conditions. Statistical tests comparing the observationally derived spin axis orientation with the outcome from simulations were applied to determine the most likely inertia moments, excitation level, and periods. Results. Under the assumption that the body is solid-rigid and rotates in torque-free conditions, the most likely interpretation is that 67P is spinning around the principal axis with the highest inertia moment with a period of about 13 h. At the same time, the comet precesses around the angular momentum vector with a period of about 6.35 h. While the rotating period of such a body would be about 12.4 h, RA/Dec coordinates of the spin axis would have a periodicity of about 270 h as a result of the combination of the two aforementioned motions.
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Dates and versions

insu-01323666 , version 1 (20-11-2020)

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Pedro J. Gutiérrez, L. Jorda, R. W. Gaskell, B. J. R. Davidsson, C. Capanna, et al.. Possible interpretation of the precession of comet 67P/Churyumov-Gerasimenko. Astronomy and Astrophysics - A&A, 2016, 590, pp.A46. ⟨10.1051/0004-6361/201528029⟩. ⟨insu-01323666⟩
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