KELT-2Ab
| Discovery | |
|---|---|
| Discovered by | T. G. Beatty et al. | 
| Discovery date | 7 June 2012 | 
| Transit | |
| Orbital characteristics | |
| 0.5504 ± 0.00086 AU (82,339,000 ± 129,000 km) | |
| Eccentricity | 0 | 
| 4.1137913 ± 0.00001 d | |
| Inclination | 88.56 ± 1.14 | 
| 2455974.60338 ± 0.00083 | |
| 90 | |
| Semi-amplitude | 161.1 ± 7.8 | 
| Star | KELT-2A | 
| Physical characteristics | |
| 1.290 ± 0.057 RJ | |
| Mass | 1.524 ± 0.088 MJ | 
| Mean density | 0.940 ± 0.090 g/cm3 | 
| 22.7 m/s2 (74 ft/s2) 2.3 g | |
| Temperature | 1994±104 K or 1782±111 K | 
KELT-2Ab is an extrasolar planet that orbits the star KELT-2A approximately 440 light-years away in the constellation of Auriga. It was discovered by the KELT-North survey via the transit method - so both its mass and radius are known quite precisely - in a paper led by Thomas Beatty. As of its discovery KELT-2Ab is the fifth-brightest transiting Hot Jupiter known that has a well constrained mass. This makes the KELT-2A system a promising target for future space- and ground-based follow-up observations to learn about the planet's atmosphere.
Water vapour was detected in planetary atmosphere in 2018.
The star KELT-2A is a member of the common-proper-motion binary star system KELT-2 (HD 42176). KELT-2B is an early K dwarf approximately 295 astronomical units away.