6236
20230127122449.0
A&A
DOI
SCART-2023-0098
Baland, Rose-Marie
Relativistic contributions to the rotation of Mars
2023
InSight contribution ICN 304
Context: The orientation and rotation of Mars, which can be described by a set of Euler angles, is estimated from radioscience data and is then used to infer Mars internal properties. The data are analyzed using a modeling expressed within the Barycentric Celestial Reference System (BCRS). Aims: We provide new and more accurate (to the 0.1 mas level) estimations of the relativistic corrections to be included in the BCRS model of the orientation and rotation of Mars to avoid a misinterpretation of the data. Methods: There are two types of relativistic contributions in Mars rotation and orientation: (i) those that directly impact the Euler angles and (ii) those resulting from the time transformation between a local Mars reference frame and BCRS. The former correspond essentially to the geodetic effect. We compute them assuming that Mars evolves on a Keplerian orbit. As for the latter, we compute the effect of the time transformation and compare the rotation angle corrections obtained using realistic orbits as described by ephemerides. Results: The relativistic correction in longitude comes mainly from the geodetic effect and results in the geodetic precession (6.754mas/yr) and the geodetic annual nutation (0.565 mas amplitude). For the rotation angle, the correction is dominated by the effect of the time transformation. The main annual, semi-annual, and ter-annual terms have amplitudes of 166.954 mas, 7.783 mas, and 0.544mas, respectively. The amplitude of the annual term differs by about 9 mas from the estimate usually considered by the community. We identify new terms at the Mars-Jupiter and Mars-Saturn synodic periods (0.567 mas and 0.102 mas amplitude) that are relevant considering the current level of uncertainty of the measurements, as well as a contribution to the rotation rate (7.3088 mas/day). There is no significant correction that applies to the obliquity.
NO
astrometry
Planets and satellites: Mars
Relativistic processes
Reference systems
Hees, AurÃ©lien
Yseboodt, Marie
Bourgoin, Adrien
Le Maistre, SÃ©bastien
Astronomy & Astrophysics
2023
rose-marie.baland@observatoire.be
2570657
http://publi2-as.oma.be/record/6236/files/Baland_aa_2023.pdf
3131
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3767
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accepted to be published in
REFERD