A&A 462, 1165-1170 (2007)
DOI: 10.1051/0004-6361:20066284

Trojan planets in HD 108874?

R. Schwarz¹, R. Dvorak², E. Pilat Lohinger², Á. Süli¹, and B. Érdi<sup>1

1</sup>  Eötvös Loránd University, Departement of Astronomy, Pázmány Péter sétány 1/A, Budapest 1518, Hungary
²  Institute for Astronomy, University of Vienna, Türkenschanzstr. 17, 1180 Wien, Austria
    e-mail: dvorak@astro.univie.ac.at

(Received 22 August 2006 / Accepted 16 October 2006)

Abstract
Aims.It turned out recently that, in addition to a large planet with a semimajor axis  AU and a low eccentricity ( ), the extrasolar planetary system HD 108874 harbors another massive planet with  AU. The inner planet is orbiting the G5 host star in the habitable zone (=HZ); so that we could established stable regions for Earth-like Trojan planets.
Methods.We integrated some 10⁵ orbits of fictitious Trojans around the Lagrangian points for up to 10⁷ years and checked the stability of the orbital elements and their chaoticity with the aid of the Fast Lyapunov Indicator.
Results.It turns out that this multiplanetary system is the first one where - with the uncertainties in eccentricity and semimajor axes of the outer planet - the existence of Trojan terrestrial planets in stable orbits in the HZ is possible for some combinations of the orbital parameters.

Key words: celestial mechanics -- chaos -- stars: planetary systems

© ESO 2007