Cometary evidence of a massive body in the outer Oort cloud
J. J. Matese1, P. G. Whitman and D. P. Whitmire
Department of Physics
The University of
Southwestern Louisiana
Lafayette, Louisiana,
70504-4210 USA
Approximately 25% of the 82 new class I Oort cloud comets have an anomalous
distribution of orbital elements that can best be understood if there exists
a bound perturber in the outer Oort cloud. Statistically significant
correlated anomalies include aphelia directions, energies, perihelion distances
and signatures of the angular momentum change due to the Galaxy. The perturber,
acting in concert with the galactic tide, causes these comets to enter
the loss cylinder - an interval of Oort cloud comet perihelion distances
in the planetary region which is emptied by interactions with Saturn and
Jupiter. More concisely, the impulse serves to smear the loss cylinder
boundary inward along the track of the perturber. Thus it is easier for
the galactic tide to make these comets observable. A smaller number of
comets are directly injected by the impulsive mechanism. We estimate that
the perturber-comet interactions take place at a mean distance of approximately
25000 AU. The putative brown dwarf would have a mass of approximately
3 MJupiter
and an orbit whose normal direction is within 5o
of the galactic midplane. This object would not have been detected in the
IRAS database, but will be detectable in the next generation of planet/brown
dwarf searches, including SIRTF. It is also possible that its radio emissions
would make it distinguishable in sensitive radio telescopes such as the
VLA.
Accepted for publicationin the journal Icarus on 19 May 1999.
Key Words:
comets, dynamics; celestial mechanics; infrared observations; jovian planets.
Pages: 24, including `
7 figures and 1 table
1Phone:
(318) 482 6697
Fax:
(318) 482 6699
E-mail:matese@usl.ed` u
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