KELT-2Ab

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title: "KELT-2Ab" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["auriga", "hot-jupiters", "transiting-exoplanets", "exoplanets-discovered-in-2012", "giant-planets", "exoplanets-discovered-by-kelt"] description: "Hot Jupiter" topic_path: "general/auriga" source: "https://en.wikipedia.org/wiki/KELT-2Ab" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Hot Jupiter ::

::data[format=table title="Infobox planet"]

Field	Value
name	KELT-2Ab
discoverer	T. G. Beatty et al.
discovered	7 June 2012
discovery_method	Transit
	apsis
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
star	KELT-2A
	mean_radius
mass	1.524 ± 0.088
density	940 ±
surface_grav	22.7 m/s2
2.3 g
single_temperature	1994 K or 1782 K
	image
::

| name = KELT-2Ab | discoverer = T. G. Beatty et al. | discovered = 7 June 2012 | discovery_method = Transit | 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 | star = KELT-2A | mean_radius = 1.290 ± 0.057 | mass = 1.524 ± 0.088 | density = 940 ± | surface_grav = 22.7 m/s2 2.3 g | single_temperature = 1994 K or 1782 K | image = KELT-II.png 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.

References

References

1. (2019). "Statistical Characterization of Hot Jupiter Atmospheres Using Spitzer's Secondary Eclipses". The Astronomical Journal.
2. [https://www.researchgate.net/publication/267759633_The_MgI_line_a_new_probe_of_the_atmospheres_of_evaporating_exoplanets The MgI line: a new probe of the atmospheres of evaporating exoplanets]
3. (2018). "Ground- and Space-based Detection of the Thermal Emission Spectrum of the Transiting Hot Jupiter KELT-2Ab". The Astronomical Journal.
4. (2012). "KELT-2Ab: A Hot Jupiter Transiting the Bright (V = 8.77) Primary Star of a Binary System". The Astrophysical Journal Letters.

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