Gliese 1214 is a dim M4.5 red dwarf in the constellation Ophiuchus with an apparent magnitude of 14.7. It is located at a distance of approximately 47 light years from Earth. The star is about one-fifth the radius of the Sun with a surface temperature estimated to be 3000 K (2730 °C; 4940 °F). Its luminosity is only 0.33% that of the Sun.
The estimate for the stellar radius is 15% larger than predicted by theoretical models. It also shows a 1% intrinsic variability in the near-infrared probably caused by stellar spots. The star is rotating slowly, with a period that is most likely an integer multiple of 53 days. It is probably at least three billion years old and a member of the old disk. Although GJ 1214 has a low to moderate level of magnetic activity, it does undergo flares and is a source of X-ray emission with a base luminosity of 7.4×1025 erg s−1. The temperature of the corona is estimated to be about 3.5×106 K.
In mid-December 2009, a team of Harvard-Smithsonian astronomers announced the discovery of a companion extrasolar planet, Gliese 1214 b, potentially composed largely of water and having the mass and diameter of a super-Earth.
(in order from star)
|b||6.55 ± 0.98 M⊕||0.0143 ± 0.0019||1.58040456 ± 1.6x10−7||<0.27||88.17°||2.64 ± 0.13 R⊕|
Discovered by the MEarth project and investigated further by the HARPS spectrograph on ESO’s 3.6-metre telescope at La Silla, GJ 1214 b is the second super-Earth exoplanet for which astronomers have determined the mass and radius, giving vital clues about its structure. It is also the first super-Earth around which an atmosphere has been found. A search for additional planets using transit timing variations was negative.
No transit-time variations have yet been found for this transit. As of 2012, "the given data does not allow us to conclude that there is a [second] planet in the mass range 0.1–5 Earth-masses and the period range 0.76–1.23 or 1.91–3.18 days." The X-ray flux from the host star is estimated to have stripped 2–5.6 M⊕ from the planet over the lifetime of the system.
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