GU Piscium b (GU Psc b) is a directly imaged planetary-mass companion orbiting the star
GU Piscium
GU Piscium is a star in the constellation Pisces. An RS Canum Venaticorum variable, it ranges from magnitude 12.96 to 13.24 over 1.04 days. It is 48 Parsecs (155 light-years) distant from Earth. This star is also believed to be a member ...
orbital revolution
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 a ...
around its parent star (which is 1/3 the mass of the Sun) or "year", would take approximately 163,000 years to complete, considering a circular orbit with 2000 AU as the semi-major axis. It is a
gas giant
A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are also called failed stars because they contain the same basic elements as a star. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" ...
Solar System
The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...
, and estimated to have a mass nine to thirteen times that of
Jupiter
Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...
, and a surface temperature of 1000 K.
It is a relatively young stellar system, part of the AB Doradus moving group of ca. 30 main stars created from the same
molecular cloud
A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit absorption nebulae, the formation of molecules (most commonly molecular hydroge ...
less than 100 million years ago, and the only one found among the 90 stars of the group examined.
Discovery
The discovery was made by an international team of astronomers led by Marie-Eve Naud of the
Université de Montréal
The Université de Montréal (UdeM; ; translates to University of Montreal) is a French-language public research university in Montreal, Quebec, Canada. The university's main campus is located in the Côte-des-Neiges neighborhood of Côte- ...
in
Quebec
Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...
, combining observations from telescopes of the
Gemini Observatory
The Gemini Observatory is an astronomical observatory consisting of two 8.1-metre (26.6 ft) telescopes, Gemini North and Gemini South, which are located at two separate sites in Hawaii and Chile, respectively. The twin Gemini telescopes prov ...
Canada–France–Hawaii Telescope
The Canada–France–Hawaii Telescope (CFHT) is located near the summit of Mauna Kea mountain on Hawaii's Big Island at an altitude of 4,204 meters (13,793 feet), part of the Mauna Kea Observatory. Operational since 1979, the telescope is a Pri ...
(CFHT) and the
W. M. 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 comp ...
. Its large distance away from its parent star permitted the use of combined infrared and visible light images to detect it, a technique astronomers hope to reproduce to discover much closer planets with the
Gemini Planet Imager
The Gemini Planet Imager (GPI) is a high contrast imaging instrument that was built for the Gemini South Telescope in Chile. The instrument achieves high contrast at small angular separations, allowing for the direct imaging and integral field spec ...
(GPI) in Chile.
Near-infrared spectroscopy of the companion was obtained with the GNIRS spectrograph on the Gemini North Telescope, which shows evidence of low surface gravity confirming the planet's youth. Weak methane absorption was detected in H and K band corresponding to a spectral type of T3.5.
See also
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List of exoplanet extremes
The following are lists of extremes among the known exoplanets. The properties listed here are those for which values are known reliably. It is important to note that the study of exoplanets is one of the most dynamic emerging fields of science, a ...
*
List of directly imaged exoplanets
This is a list of extrasolar planets that have been directly observed, sorted by observed separations. This method works best for young planets that emit infrared light and are far from the glare of the star. Currently, this list includes both d ...
*
CFBDSIR 2149−0403
CFBDSIR 2149-0403 (full designation CFBDSIR J214947.2-040308.9) is a free-floating planetary-mass object or possibly a high- metallicity, low-mass brown dwarf in the constellation Aquarius. Originally, it was thought to be part of the AB Doradu ...
- Possible rogue planet in the AB Doradus moving group
* WD 0806−661 Y-type sub-brown dwarf. It is currently the planetary-mass object with the widest known separation from its host star and it has the widest angular separation as seen from Earth (more than 2 arcminutes).