HD 46375 b
Encyclopedia
HD 46375 b is an extrasolar planet
located approximately 109 light-year
s away in the constellation
of Monoceros
, orbiting the star
HD 46375
. With 79 Ceti b
on March 29, 2000, it was joint first known extrasolar planet
less massive than Saturn
orbiting a normal star. The planet is a "hot Jupiter
", a type of planet that orbits very close to its parent star. In this case the orbital distance is only a tenth that of the planet Mercury
. No transit
of the planet has been detected, so its inclination
must be less than 83°. Because the inclination is unknown, the true mass
of the planet is not known.
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
located approximately 109 light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
s away in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
of Monoceros
Monoceros
Monoceros is a faint constellation on the celestial equator. Its name is Greek for unicorn. Its definition is attributed to the 17th-century Dutch cartographer Petrus Plancius. It is bordered by Orion to the west, Gemini to the north, Canis Major to the south and Hydra to the east...
, orbiting the star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
HD 46375
HD 46375
HD 46375 is an 8th magnitude K-type subgiant star located approximately 109 light-years away in the constellation of Monoceros. This star resembles a orange dwarf but which has a larger radius and luminosity indicating that fusion reactions in its core are starting to cease and the star is on its...
. With 79 Ceti b
79 Ceti b
79 Ceti b is an extrasolar planet orbiting its star every 75 days. With HD 46375 b on March 29, 2000, it was the joint first known extrasolar planet to have minimum mass less than the mass of Saturn.-External links:...
on March 29, 2000, it was joint first known extrasolar planet
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
less massive than Saturn
Saturn
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.Saturn,...
orbiting a normal star. The planet is a "hot Jupiter
Hot Jupiter
Hot Jupiters are a class of extrasolar planet whose mass is close to or exceeds that of Jupiter...
", a type of planet that orbits very close to its parent star. In this case the orbital distance is only a tenth that of the planet Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...
. No transit
Astronomical transit
The term transit or astronomical transit has three meanings in astronomy:* A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, hiding a small part of it, as seen by an observer at some particular vantage point...
of the planet has been detected, so its inclination
Inclination
Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...
must be less than 83°. Because the inclination is unknown, the true mass
True mass
The term true mass is synonymous with the term mass, but is used in astronomy to differentiate the measured mass of a planet from the lower limit of mass usually obtained from radial velocity techniques...
of the planet is not known.