12 Persei (12 Per) is a double-lined

spectroscopic binary A binary star is a system of two star, stars that are gravity, gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separa ...

star system A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction. A large group of stars bound by gravitation is generally called a '' star cluster'' or '' galaxy'', although, broadly speak ...

in the northern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Perseus In Greek mythology, Perseus (Help:IPA/English, /ˈpɜːrsiəs, -sjuːs/; Greek language, Greek: Περσεύς, Romanization of Greek, translit. Perseús) is the legendary founder of Mycenae and of the Perseid dynasty. He was, alongside Cadmus ...

. Its combined

apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's li ...

is 4.94, which means it can be viewed with the naked eye. Based upon

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby objects ...

measurements, this system is about 79

light year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s away from the Sun. The magnitude difference between the two components is estimated to be 0.51. Based upon this, the primary has a mass around 138% of the Sun, 155% of the Sun's radius, and shines with three times the Sun's luminosity. The smaller secondary component is also larger than the Sun, with 124% of the Sun's mass, 131% of the radius of the Sun, and has 186% of the Sun's luminosity. The stellar classification of the primary is F9 V, which suggests it is an F-type main sequence star. The pair have an estimated age of just over a billion years. The pair orbit each other with a period of 331 days and an eccentricity of 0.663. The

semimajor axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the longe ...

of their orbit is 1.27 AU, which means the inner stability radius for a hypothetical planet orbiting the pair would be at 4.35 AU. This lies outside the habitability zone for this system.

References

{{DEFAULTSORT:12 Persei Perseus (constellation) F-type main-sequence stars Persei, 12 Persei, 12 Spectroscopic binaries 012623 105.6 АВ 0788 016739 BD+39 0610