Pi Mensae b
Encyclopedia
Pi Mensae b also known as HD 39091 b, is an extrasolar planet
approximately 59 light-year
s away in the constellation
of Mensa
. The planet was announced orbiting the yellow subgiant star Pi Mensae
in October 2001.
s including Jones, Butler
, Tinney, Marcy
, Penny, McCarthy, Carter, and Pourbaix announced the discovery
of one of the most massive extrasolar planets have yet been observed. It was discovered by the Anglo-Australian Planet Search
team, using a Doppler spectrometer mounted on the Anglo-Australian Telescope
.
around the star
. The semi-major axis
of the planet to the star is 3.38 AU while the semi-minor axis
is 2.59 AU. This planet passes through the star's habitable zone
at periastron (1.21 AU) while at apastron, it passes to beyond Jupiter-Sun distance (5.54 AU). The gravitational influence of this planet would disrupt the orbit of any potentially Earth-like planet.
Pi Mensae b is over ten times more massive than Jupiter
, the most massive planet in our solar system
. It will have 10 times the surface gravity of Jupiter alone and could be incandescent (glowing). The inclination
of the orbit is not known, and it could be a brown dwarf
instead.
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...
approximately 59 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 Mensa
Mensa (constellation)
Mensa is a constellation in the southern sky, created in the 18th century. Its name is Latin for table. It covers a keystone-shaped wedge of sky stretching from approximately 4h to 7.5h of right ascension, and −71 to −85.5 degrees of declination. Other than the south polar constellation...
. The planet was announced orbiting the yellow subgiant star Pi Mensae
Pi Mensae
Pi Mensae is a yellow subgiant star in the constellation of Mensa. This star has a high proper motion. The apparent magnitude is 5.67, which can be visible to the naked eye in exceptionally dark, clear skies. It is nearly 60 ly away. The star dwarfs the Sun in terms of mass, size, luminosity,...
in October 2001.
Detection and discovery
On October 15, 2001, a team of astronomerAstronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
s including Jones, Butler
R. Paul Butler
R. Paul Butler is an astronomer who searches for extrasolar planets.He received a BA and an MS from San Francisco State University, completing a Master's thesis with Geoffrey Marcy, and then completed his doctoral studies at the University of Maryland, College Park in 1993...
, Tinney, Marcy
Geoffrey Marcy
Geoffrey W. Marcy is an American astronomer, who is currently Professor of Astronomy at the University of California, Berkeley, famous for discovering more extrasolar planets than anyone else, 70 out of the first 100 to be discovered, along with R...
, Penny, McCarthy, Carter, and Pourbaix announced the discovery
Discovery (observation)
Discovery is the act of detecting something new, or something "old" that had been unknown. With reference to science and academic disciplines, discovery is the observation of new phenomena, new actions, or new events and providing new reasoning to explain the knowledge gathered through such...
of one of the most massive extrasolar planets have yet been observed. It was discovered by the Anglo-Australian Planet Search
Anglo-Australian Planet Search
The Anglo-Australian Planet Search or AAPS is a long-term astronomical survey started in 1998 and continuing to the present. It is being carried out on the 3.9m Anglo-Australian Telescope, AAT, of the Anglo-Australian Observatory in Australia. The purpose of this survey is to catalog planets around...
team, using a Doppler spectrometer mounted on the Anglo-Australian Telescope
Anglo-Australian Telescope
The Anglo-Australian Telescope is a 3.9 m equatorially mounted telescope operated by the Australian Astronomical Observatory and situated at the Siding Spring Observatory, Australia at an altitude of a little over 1100 m...
.
Physical characteristics
Pi Mensae b has a very eccentric orbit and takes 5.89 years to revolveRevolution
A revolution is a fundamental change in power or organizational structures that takes place in a relatively short period of time.Aristotle described two types of political revolution:...
around the star
Pi Mensae
Pi Mensae is a yellow subgiant star in the constellation of Mensa. This star has a high proper motion. The apparent magnitude is 5.67, which can be visible to the naked eye in exceptionally dark, clear skies. It is nearly 60 ly away. The star dwarfs the Sun in terms of mass, size, luminosity,...
. The semi-major axis
Semi-major axis
The major axis of an ellipse is its longest diameter, a line that runs through the centre and both foci, its ends being at the widest points of the shape...
of the planet to the star is 3.38 AU while the semi-minor axis
Semi-minor axis
In geometry, the semi-minor axis is a line segment associated with most conic sections . One end of the segment is the center of the conic section, and it is at right angles with the semi-major axis...
is 2.59 AU. This planet passes through the star's habitable zone
Habitable zone
In astronomy and astrobiology, a habitable zone is an umbrella term for regions that are considered favourable to life. The concept is inferred from the empirical study of conditions favourable for Life on Earth...
at periastron (1.21 AU) while at apastron, it passes to beyond Jupiter-Sun distance (5.54 AU). The gravitational influence of this planet would disrupt the orbit of any potentially Earth-like planet.
Pi Mensae b is over ten times more massive than Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
, the most massive planet in our solar system
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
. It will have 10 times the surface gravity of Jupiter alone and could be incandescent (glowing). The 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...
of the orbit is not known, and it could be a brown dwarf
Brown dwarf
Brown dwarfs are sub-stellar objects which are too low in mass to sustain hydrogen-1 fusion reactions in their cores, which is characteristic of stars on the main sequence. Brown dwarfs have fully convective surfaces and interiors, with no chemical differentiation by depth...
instead.