The Upsilon Andromedae Planetary System

The bright F8 V star ups Andromedae was previously reported to have a 4.6 day Doppler velocity periodicity, consistent with a Jupiter-mass companion orbiting at 0.059 AU (1).
Follow-up observations by both the Lick and the AFOE planet survey programs have confirmed this periodicity, and reveal additional periodicities at 242 and 1269 days.
These imply the presence of two additional companions orbiting at 0.83 and 2.5 AU and with minimum masses of 2.0 and 4.1 Jupiter-masses respectively.

(1) AU, or astronomical unit is the average distance from the Earth to the Sun
This new discovery results from a collaborative effort between:
  • Peter Nisenson (3)
  • Robert W. Noyes (3)
  • Adam R. Contos (3), and
  • Timothy W. Brown (4)

(1) Anglo-Australian Observatory
(2) San Francisco State University and University of California, Berkeley
(3) Harvard-Smithsonian Center for Astrophysics
(4) High Altitude Observatory, National Center for Atmospheric Research
Research with the AFOE is supported by the Smithsonian Institution (SI), the National Aeronautics & Space Administration (NASA), and the National Science Foundation (NSF).

See also:

AFOE Logo There is more on the AFOE's planet detection program.

Adam Contos  (
Sylvain G. Korzennik  (

Last modified: Thu Jun 3 18:13:15 1999