000004690 001__ 4690
000004690 005__ 20200128202233.0
000004690 037__ $$aPOSTER-2020-0040
000004690 100__ $$aPou, Laurent
000004690 245__ $$aForward Modeling of the Phobos Tides and applications to the InSight Mission
000004690 260__ $$c2019
000004690 269__ $$c2019-12-13
000004690 520__ $$aBy using the VBB seismometer as a gravimeter on the surface of Mars, the InSight mission will provide long-period data suited to tidal analysis (Lognonne et al. 1996, 2019). The tidal response of Mars, due to the Sun and the Martian moons, Phobos and Deimos, provides information about the interior structure of Mars, notably on the state and size of its core: most notably, the proximity of Phobos means that degree-2, -3 -4 and further tides are all present and will be sensitive to the elastic properties of different depth ranges within Mars (Van Hoolst et al. 2003). Solar tides are larger but have the same period as major noise sources such as temperature variations. In contrast, although smaller, the Phobos tides occupy a range of frequencies separate from these major noise peaks (Pou et al. 2018). We build a forward model of the expected acceleration recorded by InSight due to the Phobos tides using ephemerides from the JPL Horizons website to take into account all the physical parameters of Phobos' orbit, such as eccentricity, inclination, obliquity and apsidal precession. The amplitudes of these tidal variations are modeled using a viscoelastic Mars model, taking into account the potential temperature of the Martian mantle; the mean lithospheric thickness; and the core state, radius and thermodynamic modeling (Rivoldini et al. 2011, Nimmo and Faul 2013, Khan et al. 2018). This model has two uses: combined with a noise model (Pou et al. 2016), it evaluates how well data processing methods such as stacking work, and how uncertain the retrieved tidal parameters are. Then, it provides a template which can be compared with the actual observations from InSight to infer the tidal amplitudes and phase lags. In order to resolve the state of the core, the tidal amplitudes will need to be measured with an uncertainty of 1% or better. The effect on the phase lag Q of the core state is different to that of varying the mantle temperature; a measurement of degree 3 Q3 and/or degree 4 Q4 to a precision of about 10% would allow these two effects to be disentangled. In addition, a status on the reduction of the data noise coming from the external sources such as thermal instrument noise (Mimoun et al. 2016, Pou et al. 2018) will be presented.
000004690 594__ $$aNO
000004690 6531_ $$aMars
000004690 6531_ $$aPhobos
000004690 6531_ $$aTides
000004690 700__ $$aNimmo, Francis
000004690 700__ $$aMimoun, David
000004690 700__ $$aGarcia, Raphaël
000004690 700__ $$aLognonné, Philippe
000004690 700__ $$aRivoldini, Attilio
000004690 773__ $$tAmerican Geophysical Union Fall Meeting 2019 San Francisco
000004690 8560_ $$fattilio.rivoldini@observatoire.be
000004690 8564_ $$s1330815$$uhttp://publi2-as.oma.be/record/4690/files/Poster AGU 2019 - Forward modeling Phobos Tide.pdf
000004690 8564_ $$s28161$$uhttp://publi2-as.oma.be/record/4690/files/Poster AGU 2019 - Forward modeling Phobos Tide.gif?subformat=icon$$xicon
000004690 8564_ $$s28864$$uhttp://publi2-as.oma.be/record/4690/files/Poster AGU 2019 - Forward modeling Phobos Tide.jpg?subformat=icon-180$$xicon-180
000004690 980__ $$aCPOSTER