HAL : hal-00689777, version 1

Code Bibliographique ADS : 2012A&A...540A..65B

DOI : 10.1051/0004-6361/201116952

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Astronomy and Astrophysics 540 (2012) A65

Dynamical parameter determinations in Pluto's system. Expected constraints from the New Horizons mission to Pluto

Laurène Beauvalet 1, Valéry Lainey 1, Jean-Eudes Arlot 1, Richard P. Binzel 1, 2

(04/2012)

Pluto is the multiple system that has been observed the longest. Yet, the masses of its smallest satellites, Nix and Hydra, which were discovered in 2005, are still imprecisely known, because of the short time span and number of available observations. We present a numerical model that takes into account the second order gravity fields and Pluto's orbital motion in the solar system. We investigated the dynamical parameters that may be reliably determined today. We also assessed the possible improvements on the parameter uncertainties with the future increase of observations, including the New Horizons mission. Fitting our model to simulated data, we show that the precision of observations prevents the quantification of the polar oblateness J2 and equatorial bulge c22 of Pluto and Charon. Similarly, we show that the masses are on the detection limit. In particular, unless 25 observations are made every year, the mass of Nix may be constrained with confidence only with New Horizons data. Hydra's mass will only be constrained by the probe. The recent discovery of P4 might change this situation, but our knowledge of this object is still too vague to draw any conclusion.

1 :	Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE)
	CNRS : UMR8028 – INSU – Observatoire de Paris – Université Pierre et Marie Curie [UPMC] - Paris VI – Université Lille I - Sciences et technologies
2 :	Department of Earth, Atmospheric, and Planetary Sciences
	Massachussetts Institute of Technology (MIT)

Domaine

:

Planète et Univers/Astrophysique/Planétologie et astrophysique de la terre Physique/Astrophysique/Planétologie et astrophysique de la terre

Mots Clés : methods: numerical – Kuiper belt: general – planets and satellites: fundamental parameters – celestial mechanics – planets and satellites: individual: Pluto

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Contributeur : Laurène Beauvalet <>

Soumis le : Vendredi 20 Avril 2012, 10:43:38

Dernière modification le : Lundi 23 Avril 2012, 10:51:43