HD 16760
Encyclopedia
HD 16760 is a binary star
system approximately 150 light-year
s away in the constellation
Perseus
. The primary star HD 16760 (HIP 12638) is a G-type main sequence star similar to our Sun. The secondary, HIP 12635 is 1.521 magnitudes fainter and located at a separation of 14.6 arcseconds from the primary, corresponding to a physical separation of at least 660 AU
. Announced in July 2009, HD 16760 has been confirmed to have a substellar object
orbiting it. Whether or not this object is a brown dwarf
or an extrasolar planet
is currently not understood.
extrasolar planets program and the N2K Consortium
. It has a mass exceeding the lower limit required for fusion of deuterium
in its interior. This criterion is sometimes used to distinguish between brown dwarfs, which lie above the limit, and planets which lie below the limit. However its orbit is nearly circular, indicating that it may have formed in the same way as planets do, from a circumstellar disc. The formation of massive planets up to 20–25 Jupiter mass
es has been predicted in some models of the core accretion process. The identity of this object as a brown dwarf or a massive planet was thus unclear.
However, recently data analysed from direct imaging, using ground based telescopes fitted with adaptive optics, on the companion object has revealed that it is aligned in a much more face on orbit than previously realised. Consequently, its mass has been revised upwards. It is now no longer believed to be a large gas giant or even a brown dwarf but with a new mass calculated at around one quarter that of our sun, or nearly 300 Jupiter masses, it easily qualifies as a stellar object, probably a red dwarf.
Binary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
system approximately 150 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....
Perseus
Perseus (constellation)
Perseus is a constellation in the northern sky, named after the Greek hero Perseus. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations defined by the International Astronomical Union...
. The primary star HD 16760 (HIP 12638) is a G-type main sequence star similar to our Sun. The secondary, HIP 12635 is 1.521 magnitudes fainter and located at a separation of 14.6 arcseconds from the primary, corresponding to a physical separation of at least 660 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
. Announced in July 2009, HD 16760 has been confirmed to have a substellar object
Substellar object
A substellar object, sometimes called a lump, is an astronomical object whose mass is smaller than the smallest mass, approximately 0.08 solar masses, at which a star can sustain hydrogen fusion...
orbiting it. Whether or not this object is 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...
or 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...
is currently not understood.
Substellar companion
The companion object was discovered independently by the SOPHIESophie
Sophie is the French and German form of the name Sophia. In English speaking countries, Sophie has also been a diminutive of Sophia.Sophie and Sophy may refer to:-People:...
extrasolar planets program and the N2K Consortium
N2K Consortium
The N2K Consortium is a collaborative multinational effort by American, Chilean and Japanese astronomers to find additional extrasolar planets around stars that are...
. It has a mass exceeding the lower limit required for fusion of deuterium
Deuterium
Deuterium, also called heavy hydrogen, is one of two stable isotopes of hydrogen. It has a natural abundance in Earth's oceans of about one atom in of hydrogen . Deuterium accounts for approximately 0.0156% of all naturally occurring hydrogen in Earth's oceans, while the most common isotope ...
in its interior. This criterion is sometimes used to distinguish between brown dwarfs, which lie above the limit, and planets which lie below the limit. However its orbit is nearly circular, indicating that it may have formed in the same way as planets do, from a circumstellar disc. The formation of massive planets up to 20–25 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 has been predicted in some models of the core accretion process. The identity of this object as a brown dwarf or a massive planet was thus unclear.
However, recently data analysed from direct imaging, using ground based telescopes fitted with adaptive optics, on the companion object has revealed that it is aligned in a much more face on orbit than previously realised. Consequently, its mass has been revised upwards. It is now no longer believed to be a large gas giant or even a brown dwarf but with a new mass calculated at around one quarter that of our sun, or nearly 300 Jupiter masses, it easily qualifies as a stellar object, probably a red dwarf.