Gliese 436 b
| Exoplanet | List of exoplanets | |
|---|---|---|
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| Parent star | ||
| Star | Gliese 436 | |
| Constellation | Leo | |
| Right ascension | (α) | 11h 42m 11.0941s |
| Declination | (δ) | +26° 42′ 23.652″ |
| Apparent magnitude | (mV) | 10.68 |
| Distance | 33.4 ± 0.8 ly (10.2 ± 0.2 pc) |
|
| Spectral type | M2.5 V | |
| Mass | (m) | 0.41 ± 0.05 M☉ |
| Radius | (r) | 0.42 R☉ |
| Temperature | (T) | 3318 K |
| Metallicity | [Fe/H] | -0.32 |
| Age | 7.41–11.05 Gyr | |
| Orbital elements | ||
| Semi-major axis | (a) | 0.0291±0.0004AU (4.35 Gm) |
| 2.85 mas | ||
| Periastron | (q) | 0.0247 AU (3.70 Gm) |
| Apastron | (Q) | 0.0335 AU (5.01 Gm) |
| Eccentricity | (e) | 0.150±0.012 |
| Orbital period | (P) | 2.643904±0.000005d (0.00723849 y) |
| (63.4537 h) | ||
| Inclination | (i) | 85.8+0.21 −0.25° |
| Argument of periastron |
(ω) | 351±1.2° |
| Time of periastron | (T0) | 2,451,551.716 ±0.01 JD |
| Semi-amplitude | (K) | 18.68±0.8 m/s |
| Physical characteristics | ||
| Mass | (m) | 22.2±1.0M⊕ |
| Radius | (r) | 4.327±0.183R⊕ |
| Stellar flux | (F⊙) | 29.5 ⊕ |
| Density | (ρ) | 1.51 g cm−3 |
| Surface gravity | (g) | 1.18 g |
| Temperature | (T) | 712±36 |
| Discovery information | ||
| Discovery date | August 31, 2004 | |
| Discoverer(s) |
Butler, Vogt, Marcy et al. |
|
| Discovery method | Radial velocity, Transit | |
| Discovery site | California, USA | |
| Discovery status | Published | |
| Other designations | ||
|
Ross 905 b, GJ 436 b,LTT 13213 b, GCTP 2704.10 b, LHS 310, AC+27:28217 b, Vyssotsky 616 b, HIP 57087 b, GEN# +9.80120068 b, LP 319-75 b, G 121-7 b, LSPM J1142+2642 b, 1RXS J114211.9+264328 b, ASCC 683818 b, G 147-68 b, UCAC2 41198281 b, BPS BS 15625-0002 b, G 120-68 b, 2MASS J11421096+2642251 b, USNO-B1.0 1167-00204205 b, CSI+27-11394 b, MCC 616 b, VVO 171 b, CSI+27-11395 b, HIC 57087 b, NLTT 28288 b, Zkh 164 b, CSI+26-11395 b, [RHG95] 1830 b, GCRV 7104 b, LFT 838 b, PM 11395+2700 b
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| Database references | ||
| Extrasolar Planets Encyclopaedia |
data | |
| SIMBAD | data | |
| Exoplanet Archive | data | |
| Open Exoplanet Catalogue | data | |
Gliese 436 b /ˈɡliːzə/ (sometimes called GJ 436 b) is a Neptune-sized exoplanet orbiting the red dwarf Gliese 436. It was the first hot Neptune discovered with certainty (in 2007) and was among the smallest-known transiting planets in mass and radius, until the much smaller Kepler exoplanet discoveries started coming in by 2010.
In December 2013, NASA reported that clouds may have been detected in the atmosphere of GJ 436 b.
Gliese 436 b was discovered in August 2004 by R. Paul Butler and Geoffrey Marcy of the Carnegie Institute of Washington and University of California, Berkeley, respectively, using the radial velocity method. Together with 55 Cancri e, it was then the first of a new class of planets with a minimum mass (M sini) similar to Neptune.
The planet was recorded to transit its star by an automatic process at NMSU on January 11, 2005, but this event went unheeded at the time. In 2007, Gillon led a team which observed the transit, grazing the stellar disc relative to Earth. Transit observations led to the determination of Gliese 436 b's exact mass and radius, both of which are very similar to Neptune. Gliese 436 b then became the smallest-known transiting extrasolar planet. The planet is about 4,000 km larger in diameter than Uranus and 5,000 km larger than Neptune and a bit more massive. Gliese 436b (also known as GJ 436b) orbits its star at a distance of 4,000,000 km or 15 times closer than Mercury's average distance from the Sun.
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