SETI public: Possible Giant Planets at Hundreds of AU in the HD141569 Disk

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Paper: astro-ph/0506208
Date: Thu, 9 Jun 2005 15:10:42 GMT (460kb)

Title: Spiral Structure when Setting up Pericentre Glow: Possible Giant
Planets
at Hundreds of AU in the HD141569 Disk

Authors: M. C. Wyatt
Comments: 13 pages, accepted by A&A
\\
This paper discusses the impact of introducing a planet on an eccentric
orbit
into a planetesimal disk. That planet's secular perturbations cause the
orbits
of the planetesimals to evolve in such a way that at any one time
planetesimals
at the same distance from the star have common pericentres and
eccentricities.
This causes the surface density distribution of an extended planetesimal
disk
to exhibit two spirals, one exterior the other interior to the planet's
orbit.
These two spirals unwind in different directions and their structure is
described by two parameters: the time since the planet was introduced and
the
planet's eccentricity. At late times the spirals become tightly wound and
the
offset centre of symmetry of the pericentre glow approximation is recovered.
Comparison with spiral structure seen in the HD141569 disk shows that its
spiral at 325 AU is similar to that caused by introducing a planet 5 Myr ago
with a mass 0.2-2M_Jup orbiting at 235-250 AU with an eccentricity of
0.05-0.2;
likewise a Saturn mass planet at 150 AU would cause structure like that seen
at
200 AU. More definitive statements about any planets orbiting HD141569 from
this model could be made once the effect of the binary companion on the disk
is
known, and once the disk's structure has been better characterised down to
100
AU, including the location of the star within the disk. The relatively young
age of this system (~5 Myr) means that if giant planets really do exist at
hundreds of AU from HD141569, this provides a unique opportunity to set
constraints on the mechanism by which those planets came to be at such large
distances.

\\ ( http://arXiv.org/abs/astro-ph/0506208 , 460kb)

• Previous message: LARRY KLAES: "SETI public: The need for small-scale turbulence in atmospheres of substellar objects"

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