Innes' star
{{short description|Star in the constellation Carina}}
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{{Starbox image
|image={{Location map|100x100|AlternativeMap=Carina_constellation_map.svg
|alt=Innes' star is located in the constellation Carina.
|caption=Location of Innes' star in the constellation Carina|border=infobox|mark=Red_pog.png|marksize=9|width=300
|label= Innes' star
|position=bottom
|lat=48.6
|long=3.9
}}|caption=
}}
{{Starbox observe
|epoch=J2000
|constell=Carina
}}
{{Starbox character
|u-b=+0.92{{cite journal
|author1=Mermilliod, J.-C.
|title=Compilation of Eggen's UBV data, transformed to UBV (unpublished)
|journal=Catalogue of Eggen's UBV Data
|date=1986 | bibcode= 1986EgUBV........0M }}
}}
{{Starbox astrometry
|prop_mo_ra=-2468.407
|prop_mo_dec=1184.175
|parallax=78.8922
|p_error=0.0319
}}
{{Starbox detail
|mass=0.35
|luminosity=0.011
|temperature=3,323
}}
{{Starbox catalog
|names={{odlist | name=Innes' star | Ci 20=624 | GJ=422 | HD=304043 | HIP=55042 | L=192-72 | LFT=784 | LHS=40 | LPM=378 | LTT=4167 | PLX=2621 | TYC=8624-3387-1}}
}}
{{Starbox reference
|Simbad=HD+304043
}}
{{Starbox end}}
Innes' star {{IPAc-en|'|I|n|I|s}}, or Gliese 422, is an M3.5-type red dwarf star, located in the constellation Carina.[http://djm.cc/constellation.html Enter 11 16 00.20551 -57 32 51.5988] 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 in Union Observatory, Union of South Africa, who had discerned its large proper motion and a parallax of 0.337 arcsec.{{cite journal |bibcode=1920CiUO...49...55W|title=Parallax and Proper Motion of a Faint Star in the Sydney Zone|journal=Circular of the Union Observatory Johannesburg|volume=49|pages=55|last1=Worssell|first1=W. M.|year=1920}} The discovery was published in Circular of the Union Observatory No. 49, hence its discovery name is UO 49,{{cite journal |bibcode=1930PCinO..20....1P|title=A catalogue of 1474 stars with proper motion exceeding four-tenths year|journal=Publications of the Cincinnati Observatory|volume=20|pages=1|last1=Porter|first1=J. G.|last2=Yowell|first2=E. J.|last3=Smith|first3=E. S.|year=1930}} 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 parallax. The estimated distance was less than 10 light-years 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 ABC, Barnard's Star and Sirius AB;{{cite journal |bibcode=1922BAN.....1...22H|title=Remark on the period of VV Orionis|journal=Bulletin of the Astronomical Institutes of the Netherlands|volume=1|pages=22|last1=Hertzsprung|first1=E.|year=1922}}
- In A study of the near-by stars by Willem Jacob Luyten and Harlow Shapley (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);{{cite journal |bibcode=1930AnHar..85...73L|title=A study of the near-by stars|journal=Annals of the Astronomical Observatory of Harvard College |volume=85|pages=73|last1=Luyten|first1=Willem Jacob|last2=Shapley|first2=Harlow|year=1930|issue=5}}
- In List of stars nearer than five parsecs by Peter van de Kamp (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, Lalande 21185, Sirius AB and BD-12 4523;{{cite journal |bibcode=1930PA.....38...17V|title=List of stars nearer than five parsecs|journal=Popular Astronomy|volume=38|pages=17|last1=Van De Kamp|first1=P.|year=1930}}
- In Stars within ten parsecs of the Sun by Louise Freeland Jenkins (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.{{cite journal |bibcode=1937AJ.....46...95J|title=Stars within ten parsecs of the sun|journal=Astronomical Journal|volume=46|pages=95|last1=Jenkins|first1=Louise F.|year=1937|doi=10.1086/105404}}
Its actual distance is {{convert|12.676|pc|ly|abbr=off}}, based on the parallax from Gaia DR3: {{val|0.07889|0.00003|fmt=none}} arcsec.
Planetary system
In 2014, a sub-Neptune-mass planet, Gliese 422 b, of approximately ten Earth-masses, was discovered around this star. It orbits the star every 20 days and lies at a distance of around 0.11 astronomical units (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.
{{OrbitboxPlanet begin
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{{OrbitboxPlanet
| exoplanet = b
| mass_earth = {{val|11.07|1.12|p=≥}}
| period = {{val|20.129|0.005}}
| semimajor = {{val|0.111|0.004}}
| eccentricity = {{val|0.11|0.04}}
}}
{{Orbitbox end}}
Name
Innes' Star is one of a few stars named after people—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: Barnard's Star, Kapteyn's Star, Luyten's Star, van Maanen's Star, van Biesbroeck's Star, and Teegarden's Star. Innes is also known as the discoverer of Proxima Centauri.
References
External links
- [https://exoplanet.eu/catalog/gj_422_b--1534/ Planet GJ 422 b]
{{Stars of Carina}}
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Category:M-type main-sequence stars
Category:Stars with proper names