HD 130948
Encyclopedia
HD 130948 or HP Boötis is a variable star
with 2 brown dwarf
s in the constellation Boötes
. It has a stellar classification
of G1V, which means it is a main sequence
star with a mass and surface temperature that are similar to the Sun
. The estimated age of this star is also similar to the Sun at 4.7 billion years (Gyr) old, but it has a lower proportion of elements (63%) other than hydrogen or helium. However, a separate study in 2009 gave a much younger age of and a higher metallicity that is very similar to the Sun.
In 2002 a pair of co-orbiting brown dwarf
s were discovered in orbit around this star. They were found using an adaptive optics instrument on the Gemini North 8m telescope in Hawaii. The pair have a 10-year orbital period about the primary star, and their combined mass is 10.9% of the Sun's mass.
The space velocity components of this star through the Milky Way
galaxy are = .
Variable star
A star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...
with 2 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...
s in the constellation Boötes
Boötes
Boötes is a constellation in the northern sky, located between 0° and +60° declination, and 13 and 16 hours of right ascension on the celestial sphere. The name comes from the Greek Βοώτης, Boōtēs, meaning herdsman or plowman...
. It has a stellar classification
Stellar classification
In astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
of G1V, which means it is a 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 with a mass and surface temperature that are similar to the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
. The estimated age of this star is also similar to the Sun at 4.7 billion years (Gyr) old, but it has a lower proportion of elements (63%) other than hydrogen or helium. However, a separate study in 2009 gave a much younger age of and a higher metallicity that is very similar to the Sun.
In 2002 a pair of co-orbiting 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...
s were discovered in orbit around this star. They were found using an adaptive optics instrument on the Gemini North 8m telescope in Hawaii. The pair have a 10-year orbital period about the primary star, and their combined mass is 10.9% of the Sun's mass.
The space velocity components of this star through the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
galaxy are = .