HD 131664
Encyclopedia
HD 131664 is an 8th magnitude
G-type main sequence
star
located approximately 181 light-year
s away in the constellation
of Apus
.
On October 26, 2008, a brown dwarf
was discovered along with five other planets (BD-17°63 b
, HD 145377 b
, HD 153950 b
, HD 73267 b
, and HD 20868 b
). This brown dwarf has mass of at least 18.15 times that of Jupiter
and orbits in a long-period, eccentric orbit.
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
G-type main sequence
Main sequence
The main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell...
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...
located approximately 181 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 Apus
Apus
Apus is a faint constellation in the southern sky, first defined in the late 16th century. Its name means "no feet" in Greek, and it represents a bird-of-paradise . It is bordered by Triangulum Australe, Circinus, Musca, Chamaeleon, Octans, Pavo and Ara...
.
On October 26, 2008, 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...
was discovered along with five other planets (BD-17°63 b
BD-17°63 b
BD-17°63 b is an extrasolar planet located approximately 113 light-years away in the constellation of Cetus, orbiting the 10th magnitude K-type main sequence star BD-17°63. This planet has a minimum mass of 5.1 MJ and orbits at a distance of 1.34 astronomical units from the star. The distance...
, HD 145377 b
HD 145377 b
HD 145377 b is an extrasolar planet located approximately 188 light-years away in the constellation of Scorpius, orbiting the 8th magnitude G-type main sequence star HD 145377. This planet orbits at a distance of 0.45 astronomical units and takes 104 days to revolve around the star with an...
, HD 153950 b
HD 153950 b
HD 153950 b is an extrasolar planet located approximately 162 light-years away in the constellation of Scorpius, orbiting the 7th magnitude F-type main sequence star HD 153950. This planet has mass about 2.73 times that of Jupiter, but because the inclination is not known, the mass value is only...
, HD 73267 b
HD 73267 b
HD 73267 b is an extrasolar planet located approximately 179 light-years away in the constellation of Pyxis, orbiting the 9th magnitude G-type main sequence star HD 73267...
, and HD 20868 b
HD 20868 b
HD 20868 b is an extrasolar planet located approximately 159 light-years away in the constellation of Fornax, orbiting the 10th magnitude K-type subgiant star HD 20868. This planet has a minimum mass of 1.99 times more than Jupiter and orbits at a distance of 0.947 AU...
). This brown dwarf has mass of at least 18.15 times that of 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,...
and orbits in a long-period, eccentric orbit.