| Discovery | |
|---|---|
| Discovered by | François Bouchy et al.[1] |
| Discovery site | Haute-Provence[1] |
| Discovery date | Published August 3, 2011[1] |
| radial velocity/transit[1] | |
| Orbital characteristics | |
| 0.155 (± 0.003)[2] AU | |
| Eccentricity | 0.121 (± 0.023)[2] |
| 21.0874 (± 0.0002)[2] d | |
| Inclination | 88.83 +0.59 −0.4[2] |
| 98.9 +5.9 −6.8[2] | |
| Star | Kepler-39 |
| Physical characteristics | |
| 1.22 +0.12 −0.10[1] RJ | |
| Mass | 18.00 +0.93 −0.91[1] MJ |
Mean density | 12.40 +3.4 −2.6[1] g cm−3 |
| Temperature | 905 K (632 °C; 1,169 °F)[1] |
Kepler-39b (formerly known as KOI-423b), is a confirmed extrasolar object (either a Jovian planet or brown dwarf because of its mass) discovered orbiting the F-type star Kepler-39. It is eighteen times more massive than Jupiter, and is about five fourths its size. The planet orbits its host star at about 15% of the average distance between the Earth and Sun. Kepler-39b's host star was investigated by European astronomers along with three other stars, including the host star of Kepler-40b, using equipment at the Haute-Provence Observatory in France. Collection and analysis of data in late 2010 led to the confirmation of Kepler-39b. The discovery paper was published in a journal on June 6, 2011.
The location of the subgiant star in the night sky is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The Right Ascension is how far expressed in time (hh:mm:ss) the star is along the celestial equator. If the R.A. is positive then its eastwards. The Declination is how far north or south the object is compared to the celestial equator and is expressed in degrees. For Kepler-39, the location is 19h 47m 50.00 and 46° 02` 04.00 .