[Previous] | [Session 32] | [Next]
G. Gatewood (UPitt,AO)
We have tested our 112 Multichannel Astrometric Photometer (MAP) (Gatewood 1987, AJ 94, 213) observations (beginning in 1988) of Epsilon Eridani against the orbital elements provided to us by W. Cochran (private communication). The reduction algorithm is detailed most recently by Gatewood, Han, and Black (2000 ApJ Letters, in press). The seven year period is clearly shown in a variance vs trial periods plot. Although it is near the limit of the current instrument, the astrometric orbital motion is apparent in the residuals to a standard derivation of the star's proper motion and parallax. The astrometric orbital parameters derived by forcing the spectroscopic elements are: semimajor axis = 1.51 +/- 0.44 mas, node of the orbit on the sky = 120 +/- 28 deg, inclination out of the plane of the sky = 46 +/- 17 deg, actual mass = 1.2 +/- 0.33 times that of Jupiter. Our study confirms this object (this is not a minimum mass) as the nearest extrasolar Jupiter mass companion to our solar system. In view of its large orbital eccentricity, however, its exact nature remains unclear.
If you would like more information about this abstract, please follow the link to http:/www.pitt.edu/~aobsvtry/. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.