HD 156846 b is an 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...

 located approximately 160 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 Ophiuchus

Ophiuchus

Ophiuchus is a large constellation located around the celestial equator. Its name is from the Greek "serpent-bearer", and it is commonly represented as a man grasping the snake that is represented by the constellation Serpens. Ophiuchus was one of the 48 constellations listed by the 2nd-century...

, 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 156846

HD 156846

HD 156846 is a G-type main sequence star of magnitude 6.5, located approximately 160 light-years away in the Ophiuchus constellation. The star has an M4 companion and a planet.- Planetary system :...

. It has one of the most eccentric planetary orbits known. The high eccentricity of this planet's orbit is probably attributable to the presence of a 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 star. The average distance of the planet from HD 156846

HD 156846

HD 156846 is a G-type main sequence star of magnitude 6.5, located approximately 160 light-years away in the Ophiuchus constellation. The star has an M4 companion and a planet.- Planetary system :...

 is 0.99 AU

Astronomical unit

An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....

, nearly identical to the distance of Earth from the Sun. The distance ranges from 0.15 AU to 1.83 AU with a 360 day period. It is also very massive with at least 10.45 Jupiter mass

Jupiter mass

Jupiter mass , is the unit of mass equal to the total mass of the planet Jupiter . Jupiter mass is used to describe masses of the gas giants, such as the outer planets and extrasolar planets. It is also used in describing brown dwarfs....

es, however the mass is a lower limit because 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. If its inclination and hence 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...

 became known, it would probably be found to 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...

.