Gliese 15 Ab (GJ 15 Ab), also commonly called Groombridge 34 Ab,
[In the discovery paper, discoverers call this object "Gl 15 Ab", and never "Groombridge 34 Ab".] rarely called GX Andromedae b is an
extrasolar planet
An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...
approximately 11
light-years away in the
constellation of
Andromeda. It is found in the night sky orbiting the star
Gliese 15 A, which is at
right ascension 00h 18m 22.89s and
declination +44
° 01′ 22.6″.
[F. van Leeuwen (2007]
Validation of the new Hipparcos reduction
Astronomy and Astrophysics 474 (2): 653–664.
It was discovered in August 2014, deduced from analysis of the
radial velocities
The radial velocity or line-of-sight velocity, also known as radial speed or range rate, of a target with respect to an observer is the rate of change of the distance or range between the two points. It is equivalent to the vector projection o ...
of the parent star by the Eta-Earth Survey using HIRES at
Keck Observatory
The W. M. Keck Observatory is an astronomical observatory with two telescopes at an elevation of 4,145 meters (13,600 ft) near the summit of Mauna Kea in the U.S. state of Hawaii. Both telescopes have aperture primary mirrors, and when co ...
. It has around 5.35 ± 0.75
Earth masses,
[Andrew Howard, ]Geoffrey Marcy
Geoffrey William Marcy (born September 29, 1954) is an American astronomer. He was an early influence in the field of exoplanet detection, discovery, and characterization. Marcy was a professor of astronomy at the University of California, Berke ...
, Debra A. Fischer, Howard Isaacson, Philip S. Muirhead, Gregory W. Henry, Tabetha S. Boyajian
Tabetha "Tabby" Suzanne Boyajian is an American astronomer of Armenian descent and astrophysics, astrophysicist on faculty (academic staff), faculty at Louisiana State University. She was a post-doctoral fellow 2012–16 at Yale University, workin ...
, Kaspar von Braun, Juliette C. Becker, Jason T. Wright, John Asher Johnson
Astrophysics Earth and Planetary Astrophysics : The NASA-UC-UH Eta-Earth Program: IV. A Low-mass Planet Orbiting an M Dwarf 3.6 PC from Earth
and is thought to be a
Super-Earth
A super-Earth is an extrasolar planet with a mass higher than Earth's, but substantially below those of the Solar System's ice giants, Uranus and Neptune, which are 14.5 and 17 times Earth's, respectively.
The term "super-Earth" refers only to ...
with a diameter greater than that of the Earth. However, researches using the
CARMENES spectrograph failed to detect the planet in 2017.
The detection of planet was recovered in 2018, with revised minimum mass of 3.03 .
Gliese 15 Ab has a close inner orbit around Gliese 15 A with a semi-major axis of only 0.0717 ± 0.0034
AU, making an
orbit
In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as ...
al period that is just a little longer than 11.4
days, the orbit appears to be relatively circular, with an
orbital eccentricity of about 0.12. It orbits too close to
Gliese 15 A to be located in the
habitable zone
In astronomy and astrobiology, the circumstellar habitable zone (CHZ), or simply the habitable zone, is the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressure.J. F. Kast ...
and is unlikely to harbour life.
Notes
References
External links
Open Exoplanet Catalogue entry
Andromeda (constellation)
Exoplanets discovered in 2014
Terrestrial planets
Exoplanets detected by radial velocity
Hot Neptunes
1
0015
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fr:Gliese 15#Les planètes GJ 15 Ab et GJ 15 Ac