SETI public: Origin and Ubiquity of Short-Period Earth-like Planets: Evidence for the Sequent

• Previous message: LARRY KLAES: "SETI public: Catalog of 156 confirmed extrasolar planets and their 133 parent stars"

Paper: astro-ph/0508305
Date: Sat, 13 Aug 2005 07:49:49 GMT (660kb)

Title: Origin and Ubiquity of Short-Period Earth-like Planets: Evidence for
the
Sequential-Accretion Theory of Planet Formation

Authors: J.L. Zhou, S.J. Aarseth, D.N.C. Lin, M. Nagasawa

Comments: 13 pages, 3 figures, Accepted for publication in ApJL
\\
The formation of gas giant planets is assumed to be preceded by the
emergence
of solid cores in the conventional sequential-accretion paradigm. This
hypothesis implies that the presence of earth-like planets can be inferred
from
the detection of gas giants. A similar prediction cannot be made with the
gravitational instability (hereafter GI) model which assumes that gas giants
(hereafter giants) formed from the collapse of gas fragments analogous to
their
host stars. We propose an observational test for the determination of the
dominant planet-formation channel. Based on the sequential-accretion
(hereafter
SA) model, we identify several potential avenues which may lead to the
prolific
formation of a population of close-in earth-mass ($M_\oplus$) planets
(hereafter close-in earths) around stars with 1) short-period or 2) solitary
eccentric giants and 3) systems which contain intermediate-period resonant
giants. In contrast, these close-in earths are not expected to form in
systems
where giants originated rapidly through GI. As a specific example, we
suggest
that the SA processes led to the formation of the 7.5 $M_\oplus$ planet
around
GJ 876 and predict that it may have an atmosphere and envelope rich in O$_2$
and liquid water. Assessments of the ubiquity of these planets will lead to
1)
the detection of the first habitable terrestrial planets, 2) the
verification
of the dominant mode of planet formation, 3) an estimate of the fraction of
earth-harboring stars, and 4) modification of bio-marker signatures.

\\ ( http://arXiv.org/abs/astro-ph/0508305 , 660kb)

• Previous message: LARRY KLAES: "SETI public: Catalog of 156 confirmed extrasolar planets and their 133 parent stars"

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