85 Pegasi
Encyclopedia
85 Pegasi is a multiple star system 40.5 light years away in the constellation
of Pegasus
. The primary component is sixth magnitude
85 Pegasi A, which is a yellow dwarf
like our Sun
. The secondary component, 85 Pegasi B, is a ninth magnitude orange dwarf
that takes 26.28 years to orbit at 10.3 AU
around the primary in an elliptical orbit. The orbital distance ranges from 6.4 AU at periastron to 14.2 AU at apastron. 85 Peg BA may have a close, faint red dwarf
companion 85 Peg BB within 2 AU from BA. The mass would be 11% solar mass
. All components in the star system
including Star A are smaller, cooler and less massive, luminous, and metallic than our Sun and 51 Pegasi
.
As of 2010, no known extrasolar planet
s have been detected around 85 Pegasi, but 51 Pegasi has a hot Jupiter
planet, which was the first exoplanet discovered to be orbiting around an ordinary star.
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 Pegasus
Pegasus (constellation)
Pegasus is a constellation in the northern sky, named after the winged horse Pegasus in Greek mythology. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations.-Stars:...
. The primary component is sixth magnitude
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...
85 Pegasi A, which is a yellow dwarf
Yellow dwarf
A G-type main-sequence star , often called a yellow dwarf, is a main-sequence star of spectral type G and luminosity class V. Such a star has about 0.8 to 1.2 solar masses and surface temperature of between 5,300 and 6,000 K., Tables VII, VIII...
like our 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 secondary component, 85 Pegasi B, is a ninth magnitude orange dwarf
Orange dwarf
A K-type main-sequence star , also referred to orange dwarf, are main-sequence stars of spectral type K and luminosity class V. These stars are intermediate in size between red M-type main-sequence stars and yellow G-type main-sequence stars...
that takes 26.28 years to orbit at 10.3 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
around the primary in an elliptical orbit. The orbital distance ranges from 6.4 AU at periastron to 14.2 AU at apastron. 85 Peg BA may have a close, faint red dwarf
Red dwarf
According to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool star, of the main sequence, either late K or M spectral type....
companion 85 Peg BB within 2 AU from BA. The mass would be 11% solar mass
Solar mass
The solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies...
. All components in the star system
Star system
A star system or stellar system is a small number of stars which orbit each other, bound by gravitational attraction. A large number of stars bound by gravitation is generally called a star cluster or galaxy, although, broadly speaking, they are also star systems.-Binary star systems:A stellar...
including Star A are smaller, cooler and less massive, luminous, and metallic than our Sun and 51 Pegasi
51 Pegasi
51 Pegasi is a Sun-like star located 15.6 parsecs from Earth in the constellation Pegasus...
.
As of 2010, no 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...
s have been detected around 85 Pegasi, but 51 Pegasi has a hot Jupiter
Hot Jupiter
Hot Jupiters are a class of extrasolar planet whose mass is close to or exceeds that of Jupiter...
planet, which was the first exoplanet discovered to be orbiting around an ordinary star.