Innes' star (Gliese 422) is an M3.5-type

red dwarf ''Red Dwarf'' is a British science fiction comedy franchise created by Rob Grant and Doug Naylor, which primarily consists of a television sitcom that aired on BBC Two between 1988 and 1999, and on Dave since 2009, gaining a cult following. T ...

, located in

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 ...

Carina. It has around 35% of the mass of the Sun, yet only 1.1% of its luminosity, and an estimated surface temperature of 3,323 K.

Discovery

Innes' star was discovered in 1920 by

Robert T. A. Innes Robert Thorburn Ayton Innes FRSE FRAS (10 November 1861 – 13 March 1933) was a Scottish astronomer best known for discovering Proxima Centauri in 1915, and numerous binary stars. He was also the first astronomer to have seen the Great January ...

Union Observatory Union Observatory also known as Johannesburg Observatory ( 078) is a defunct astronomical observatory in Johannesburg, South Africa that was operated between 1903 and 1971. It is located on Observatory Ridge, the city's highest point at 1,808 met ...

Union of South Africa The Union of South Africa ( nl, Unie van Zuid-Afrika; af, Unie van Suid-Afrika; ) was the historical predecessor to the present-day Republic of South Africa. It came into existence on 31 May 1910 with the unification of the Cape, Natal, Trans ...

, who had discerned its large

proper motion Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more dista ...

and a

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 ...

of 0.337 arcsec. The discovery was published in ''Circular of the Union Observatory'' No. 49, hence its discovery name is ''UO 49'', or ''In UOC 49''. However, ''UO'' designations should be used with caution since they are often not unique for each star: the number in the name is the number of ''Circular'', so all stars published in one ''Circular'' have identical names. So, all other newfound stars, published in the 49th ''Circular'', may be named ''UO 49'' too.

Erroneous parallax

It is known for the fact that it had once been considered one of the nearest stars to Earth, due to erroneously measured

. The estimated distance was less than 10

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 in the following studies: *In ''List of stars nearer than 5 parsecs'' by Ejnar Hertzsprung (1922) its parallax is 0.339 arcsec (distance is 2.95 pc or 9.62 ly), and it is the 4th-closest star system after

Alpha Centauri Alpha Centauri ( Latinized from α Centauri and often abbreviated Alpha Cen or α Cen) is a triple star system in the constellation of Centaurus. It consists of 3 stars: Alpha Centauri A (officially Rigil Kentaurus), Alpha Centaur ...

ABC,

Barnard's Star Barnard's Star is a red dwarf about six light-years from Earth in the constellation of Ophiuchus. It is the fourth-nearest-known individual star to the Sun after the three components of the Alpha Centauri system, and the closest star in the ...

and

Sirius Sirius is the list of brightest stars, brightest star in the night sky. Its name is derived from the Ancient Greek language, Greek word , or , meaning 'glowing' or 'scorching'. The star is designated α Canis Majoris, Latinisation ...

AB; *In ''A study of the near-by stars'' by Willem Jacob Luyten and

Harlow Shapley Harlow Shapley (November 2, 1885 – October 20, 1972) was an American scientist, head of the Harvard College Observatory (1921–1952), and political activist during the latter New Deal and Fair Deal. Shapley used Cepheid variable stars to estim ...

(1930) its parallax is 0.337 arcsec (distance is 2.97 pc or 9.68 ly), and it is the 4th-closest star system after Alpha Centauri ABC, Barnard's Star and 22 H Camelopardalis (Sirius is further); *In ''List of stars nearer than five parsecs'' by

Peter van de Kamp Piet van de Kamp (December 26, 1901 in Kampen (Overijssel), KampenLaurence W. Fredrick, Peter van de Kamp (1901–1995)', Publications of the Astronomical Socitiey of the Pacific 108:556–559, July 1996 – May 18, 1995 in Amsterdam), known a ...

(1930) its parallax is 0.34 arcsec (distance is 2.94 pc or 9.59 ly), and it is the 7th-closest star system after Alpha Centauri ABC, Barnard's Star,

Wolf 359 Wolf 359 is a red dwarf star located in the constellation Leo, near the ecliptic. At a distance of approximately 7.9 light years from Earth, it has an apparent magnitude of 13.54 and can only be seen with a large telescope. Wolf 359 i ...

Lalande 21185 Lalande 21185 (also known as BD+36 2147, Gliese 411, and HD 95735) is a star in the south of Ursa Major. It is the apparent brightest red dwarf in the northern hemisphere.Only AX Microscopii and Lacaille 9352, in the southern hemisphere ...

, Sirius AB and BD-12 4523; *In ''Stars within ten parsecs of the Sun'' by

Louise Freeland Jenkins Louise Freeland Jenkins (July 5, 1888 – May 9, 1970) was an American astronomer who compiled a valuable catalogue of stars within 10 parsecs of the sun, as well as editing the 3rd edition of the Yale Bright Star Catalogue. She was born in Fit ...

(1937) its parallax is 0.34 arcsec (distance is 2.94 pc or 9.59 ly), and it is the 6th-closest star system after Alpha Centauri, Barnard's Star, Wolf 359, Lalande 21185 and Sirius. Its actual distance is 12.667 parsecs, or 41.32 light-years, based on parallax by van Leeuwen (2007) and Gaia DR2:Gaia DR2 parallaxes archive
/ref> arcsec.

Planetary system

In 2014, a Mega-Earth or a mini-Neptune, GJ 422 b, of approximately ten Earth-masses, was discovered in the system of this star, orbiting the star every 20 days and lying at a distance of around 0.11

astronomical unit The astronomical unit (symbol: au, or or AU) is a unit of length, roughly the distance from Earth to the Sun and approximately equal to or 8.3 light-minutes. The actual distance from Earth to the Sun varies by about 3% as Earth orbits t ...

s (AU)—11% of the distance between the Earth and Sun—on the inner edge of the stellar system's habitable zone, which for this star has been calculated to lie between 0.11 and 0.21 AU. The discovery of GJ 422 b was confirmed in 2020.

Name

Innes' Star is one of a few

stars named after people Over the past few centuries, a small number of stars have been named after individual people. It is common in astronomy for objects to be given names, in accordance with accepted astronomical naming conventions. Most stars have not been given Prope ...

—named after a scientist, whereas the majority of proper names of stars have ancient origins or medieval, in the main Arabic, ones. Certain stars, found to be nearby due to their large proper motion, also fall into this class and are named after their discoverers:

Kapteyn's Star Kapteyn's Star is a class M1 red subdwarf about 12.83 light-years from Earth in the southern constellation Pictor; it is the closest halo star to the Solar System. With a magnitude of nearly 9 it is visible through binoculars or a teles ...

Luyten's Star Luyten's Star (GJ 273) is a red dwarf in the constellation Canis Minor located at a distance of approximately from the Sun. It has a visual magnitude of 9.9, making it too faint to be viewed with the unaided eye. It is named after ...

van Maanen's Star Van Maanen 2, or van Maanen's Star, is the closest known solitary white dwarf to the solar system. It is a dense, compact stellar remnant no longer generating energy and has equivalent to about 68% of the Sun's mass but only 1% of its r ...

, van Biesbroeck's Star, and Teegarden's Star. Innes is also known as the discoverer of

Proxima Centauri Proxima Centauri is a small, low-mass star located away from the Sun in the southern constellation of Centaurus. Its Latin name means the 'nearest tarof Centaurus'. It was discovered in 1915 by Robert Innes and is the nearest-kno ...

References

External links

Planet GJ 422 b
{{DEFAULTSORT:Innes' star M-type main-sequence stars Stars with proper names 304043 0422 055042 Carina (constellation) ? Discoveries by Robert T. A. Innes