The Stability of Exoplanets in the Binary Gliese 86 AB

Pilat-Lohinger, Elke and Funk, Barbara (2006) The Stability of Exoplanets in the Binary Gliese 86 AB. In: 4th Austrian-Hungarian Workshop on Celestial Mechanics Edited by Á. Süli, F. Freistetter, A. Pál. Publications of the Astronomy Department of the Eötvös University (18). ELTE Sokszorosítóüzeme, Budapest, pp. 103-118.

Preview

Text padeu_vol18_pilat-lohinger_etal.pdf - Published Version Download (9MB) | Preview

Abstract

Gliese 86 is one of 3 binary systems with a close stellar component, where an extra-solar planet was discovered. The host-star is classified as a K1 mainsequence star and its stellar companion was first identified as a brown dwarf (Els et al., 2001) and later as a white dwarf (Mugrauer & Neuhäuser, 2005). In our numerical investigation we determine the stable zone around the K1V star for different eccentricities of the binary system in both stellar configurations and compare the results of the systems. The planetary motion is analyzed by means of (a) the Fast Lyapunov Indicator (FLI) and (b) the maximum eccentricity (max-e). A study of mean motion resonances in the Gliese 86 system showed that the perturbative effects due to the discovered planet are restricted to very close orbits. Therefore, we distinguish 3 regions: (i) the inner zone (IZ), which is the region between the detected planet and the so-called habitable zone; (ii) the habitable zone (HZ) is defined as the region around a star where liquid water can exist on the surface of a terrestrial-like planet; and (iii) the outer zone (OZ) which is the region outside the HZ, which is not influenced by the detected giant planet. For the computations different dynamical models were applied - i.e. the restricted four body problem for the (IZ) and the HZ, the elliptic restricted three body problem for the (OZ). In general, the motion of fictitious planets in the Gliese 86 system is very stable. Only for high eccentricities of the binary (≥ 0.75) chaotic motion occurs even in the HZ. In this case the stable zone shrinks to a small region around Gliese 86, where the eccentricity of an additional fictitious planet should be < 0.5 due to perturbations of the detected giant planet.

Actions (login required)

Edit Item