Andromedae upsilon

Upsilon Andromedae (υ Andromedae/Ups And) is a binary star, distant of 44 light-years in the Constellation of Andromède.

The system contains a dwarf yellow-white (Upsilon Andromedae A) similar to the Sun and weak a Naine red (Upsilon Andromedae B). The two stars are separated from 750 units astronomical (UA). Upsilon Andromedae has is of spectral Type F8V, slightly younger, more massive and luminous but with the same metalicity and the same radiation Ultraviolet.

Since 1997, three Exoplanète S were discovered in orbit of Upsilon Andromedae A. All three are masses comparable or higher than Jupiter.

Upsilon Andromedae was at the same time the first Planetary system having several planets discovered with the turn of a star of the principal sequence and around a double star.

Upsilon Andromedae has is classified 21e on the list of 100 “target” stars of the mission Terrestrial Planet Finder of NASA.

Planetary system

The planet nearest (0.06 UA) to Andromedae Upsilon has system Upsilon Andromedae B, was discovered by measuring the variations of radial Speed of star due to gravity and appears to be responsible for an activity reinforced of the Chromosphère of its star.

Two more distant planets were discovered and baptized Upsilon Andromedae C and D to 0.8 and 2.54 UA respectively, with orbits more eccentric than Pluton. Upsilon Andromedae D is in the livable Zone system, with a slope of 155° and a mass from 9 to 10 times that of Jupiter.

The existence of too small or more distant another planets is not drawn aside, although the presence of B, C, D so ready of their star would make the system unstable. Simulations show that the eccentricity of this system can have been of with a meeting between C and one 4th planet which was ejected or destroyed.

See too

• 51 Pegasi
• PSR 1257+12

References