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 5 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

Click here for a site containing a complete preprint available in .ps and .pdf formats