From: Amara Graps (amara@amara.com)
Date: Thu Jan 30 2003 - 02:14:17 MST
No, I haven't read it, but I suggest starting here for this this author's
work on this topic. Generally, I do not trust anything written by BBC's
science writer: David Whitehouse.
Amara
http://xxx.lanl.gov/abs/astro-ph/0210006
Astrophysics, abstract
astro-ph/0210006
From: Kristen Menou <km5yj@astsun.astro.virginia.edu>
Date: Mon, 30 Sep 2002 20:56:05 GMT (115kb)
Dynamical Habitability of Known Extrasolar Planetary Systems
Authors: Kristen Menou, Serge Tabachnik
Comments: 38 pages, 7 tables, 7 figures, accepted for publication in ApJ
Habitability is usually defined as the requirement for a
terrestrial planet's atmosphere to sustain liquid water. This
definition can be complemented by the dynamical requirement that
other planets in the system do not gravitationally perturb
terrestrial planets outside of their habitable zone, the orbital
region allowing the existence of liquid water. We quantify the
dynamical habitability of 85 known extrasolar planetary systems
via simulations of their orbital dynamics in the presence of
potentially habitable terrestrial planets. When requiring that
habitable planets remain strictly within their habitable zone at
all time, the perturbing influence of giant planets extends beyond
the traditional Hill sphere for close encounters: terrestrial
planet excursions outside of the habitable zone are also caused by
secular eccentricity variations and, in some cases, strong
mean-motion resonances. Our results indicate that more than half
the known extrasolar planetary systems (mostly those with distant,
eccentric giant planets) are unlikely to harbor habitable
terrestrial planets. About 1/4 of the systems (mostly those with
close-in giant planets), including 1/3 of the potential targets
for the Terrestrial Planet Finder, appear as dynamically habitable
as our own Solar System. The influence of yet undetected giant
planets in these systems could compromise their dynamical
habitability. Some habitable terrestrial planets in our
simulations have substantial eccentricities (e > 0.1) which may
lead to large seasonal climate variations and thus affect their
habitability.
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-- Amara Graps, PhD Istituto di Fisica delle Spazio Interplanetario (IFSI) Consiglio Nazionale delle Ricerche (CNR), Roma, ITALIA Amara.Graps@ifsi.rm.cnr.it
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