55 Cancri b
55 Cancri b (abbreviated 55 Cnc b), occasionally designated 55 Cancri Ab (to distinguish it from the star 55 Cancri B), also named Galileo, is an exoplanet orbiting the Sun-like star 55 Cancri A every 14.65 days. It is the second planet in order of distance from its star, and is an example of a hot Jupiter, or possibly rather "warm Jupiter".
Artist's impression of 55 Cancri b. | |
| Discovery | |
|---|---|
| Discovered by | Butler, Marcy |
| Discovery site | California, USA |
| Discovery date | April 12, 1996 |
Detection method | Radial velocity |
| Orbital characteristics | |
| Apastron | 0.116 AU (17,400,000 km) |
| Periastron | 0.113 AU (16,900,000 km) |
Semi-major axis | 0.115 ± 0.0000011 AU (17,203,760 ± 160 km) |
| Eccentricity | 0.014 ± 0.008 |
Orbital period (sidereal) | 14.65162 ± 0.0007 d 0.04011325 y |
| Inclination | ~85 |
| 2,450,002.94749 ± 1.2 | |
| 131.94 ± 30 | |
| Semi-amplitude | 71.32 ± 0.41 |
| Star | 55 Cancri A |
| Physical characteristics | |
| Mass | 0.824 ± 0.007 MJ |
In July 2014 the International Astronomical Union launched NameExoWorlds, a process for giving proper names to certain exoplanets and their host stars. The process involved public nomination and voting for the new names. In December 2015, the IAU announced the winning name was Galileo for this planet. The winning name was submitted by the Royal Netherlands Association for Meteorology and Astronomy of the Netherlands. It honors early-17th century astronomer and physicist Galileo Galilei.