| KELT-2Ab | |
| Discoverer: | KELT-North |
| Discovered: | 7 June 2012 |
| Apsis: | astron |
| Semimajor: | 0.5504± |
| Eccentricity: | 0 |
| Period: | 4.1137913 ± 0.00001 d |
| Inclination: | 88.56 ± 1.14 |
| Time Periastron: | 2455974.60338 ± 0.00083 |
| Arg Peri: | 90 |
| Semi-Amplitude: | 161.1 ± 7.8 |
| Mean Radius: | 1.290 ± 0.057 |
| Mass: | 1.524 ± 0.088 |
| Surface Grav: | 22.7m/s2 2.3 g |
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.[1]
The 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.