File:Artist_impression_of_the_exoplanet_51_Pegasi_b.jpg · Wikimedia Commons · See Wikimedia Commons
Astronomical data · SIMBAD
- Object type
- Pl
- Distance
- 51 light-years
- Coordinates
- RA 344.3666° · Dec 20.7688°
via SIMBAD · CDS Strasbourg
Key facts
- Discovered by
- Michel Mayor and, Didier Queloz
- Discovery site
- OHP , France
- Discovery date
- 6 October 1995 ; 30 years ago ( 6 October 1995 )
- Detection method
- Radial velocity ( ELODIE )
- Alternative names
- Dimidium
- Semi major axis
- 0.052 344 942 (2) au (7,830,691.9 km)
- Eccentricity
- <0.0063
- Orbital period sidereal
- 4.230 7966 ± 0.000 0027 days
- Inclination
- 49.8° +5.8°, −5.7°
- Semi amplitude
- 55.77 ± 0.15 km/s
- Star
- 51 Pegasi
- Mean radius
- 1.07 ± 0.14 R J
- Mass
- 0.61 +0.06, −0.05 M J
- Surface gravity
- 10 cgs
- Temperature
- 1,250 K
via Wikipedia infobox
Wikidata facts
- Instance of
- star
- Constellation
- Pegasus
- Parent body
- 51 Pegasi
- Radius
- 1.9
- Mass
- 0.47
- Orbital period
- 4.2308
- Image
- Artist impression of the exoplanet 51 Pegasi b.jpg
Show 20 more facts
- discoverer or inventor
- Michel Mayor
- time of discovery or invention
- 1995-11-00
- discovery method
- Doppler spectroscopy
- catalog code
- TIC 139298196b
- Commons category
- 51 Pegasi b
- right ascension
- 344.36658506978085
- declination
- 20.76882840019833
- epoch
- J2000.0
- orbital eccentricity
- 0.0042
- name
- Dimidium
- semi-major axis of an orbit
- 0.052
- argument of periapsis
- 54.1
- orbital inclination
- 80
- albedo
- 0.5
- M sin i
- 0.46
- right ascension component of proper motion
- 207.363
- declination component of proper motion
- 62.094
- parallax
- 64.6488
- on focus list of Wikimedia project
- Wikipedia:Vital articles/Level/4
- time of periapsis
- 2450404.4
via Wikidata · CC0
~7 min read
Encyclopedic overview
51 Pegasi b, officially named Dimidium (/dɪˈmɪdiəm/), is an extrasolar planet approximately 50 light-years (15 parsecs) away in the constellation of Pegasus. It was the first exoplanet to be discovered orbiting a main-sequence star, the Sun-like 51 Pegasi, and marked a breakthrough in astronomical research. It is the prototype for a class of planets called hot Jupiters.
In 2017, traces of water were discovered in the planet's atmosphere. In 2019, the Nobel Prize in Physics was awarded in part for the discovery of 51 Pegasi b.
Excerpted from Wikipedia’s “51 Pegasi b” article, available under the CC BY-SA 4.0 licence.