EDP Sciences
Free Access
Volume 398, Number 1, January IV 2003
Page(s) L1 - L4
Section Letters
DOI https://doi.org/10.1051/0004-6361:20021805
Published online 14 January 2003

A&A 398, L1-L4 (2003)
DOI: 10.1051/0004-6361:20021805


Planets in habitable zones:

A study of the binary Gamma Cephei
R. Dvorak, E. Pilat-Lohinger, B. Funk and F. Freistetter

Institute for Astronomy, University of Vienna, Türkenschanzstrasse 17, 1180 Vienna, Austria
(Received 13 November 2002 / Accepted 5 December 2002)

The recently discovered planetary system in the binary  $\gamma$ Cep was studied concerning its dynamical evolution. We confirm that the orbital parameters found by the observers are in a stable configuration. The primary aim of this study was to find stable planetary orbits in a habitable region in this system, which consists of a double star ( a=21.36 AU) and a relatively close ( a=2.15 AU) massive ( $1.7~m_{\rm jup}\sin i$) planet. We did straightforward numerical integrations of the equations of motion in different dynamical models and determined the stability regions for a fictitious massless planet in the interval of the semimajor axis $0.5~{\rm AU} < a <1.85~{\rm AU}$ around the more massive primary. To confirm the results we used the Fast Lyapunov Indicators (FLI) in separate computations, which are a common tool for determining the chaoticity of an orbit. Both results are in good agreement and unveiled a small island of stable motions close to 1 AU up to an inclination of about  $15^\circ $ (which corresponds to the 3:1 mean motion resonance between the two planets). Additionally we computed the orbits of earthlike planets (up to 90 earthmasses) in the small stable island and found out, that there exists a small window of stable orbits on the inner edge of the habitable zone in  $\gamma$ Cep even for massive planets.

Key words: stars: individual: $\gamma$ Cep -- stars: planetary systems -- habitable zones

Offprint request: R. Dvorak, dvorak@astro.univie.ac.at

SIMBAD Objects

© ESO 2003

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.