What is Upsilon Andromedae d?
[[File:UpsilonAndromedae D moons.jpg|thumb|An [[artist]] version of Upsilon Andromedae D]] '''Upsilon Andromedae d''' is an [[extrasolar planet]]. It [[orbit]]s the [[Sun]]-like [[star]] Upsilon Andromedae A. Upsilon Andromedae A was the third star known to [[wikt:host|host]] a multiple-planet [[planetary system]], the others are the Sun and the [[pulsar]] PSR 1257+12. In 1999, two groups of astronomers independently concluded that a three-planet model best fit the data.<ref>{{cite journal | url=http://www.iop.org/EJ/article/0004-637X/526/2/916/40403.html | author=Butler R.P. | display-authors = etal | title=Evidence for multiple companions to υ Andromedae | journal=Astrophysical Journal | volume=526 | issue=2 | pages=916–927 | year=1999 | doi=10.1086/308035 | bibcode=1999ApJ...526..916B| s2cid=123172934 }}</ref> The two new planets were designated Upsilon Andromedae C and Upsilon Andromedae D. == References== {{reflist}} [[Category:Exoplanets]]