Pherkad Minor
Authors: Eric Mamajek, Susanne M Hoffmann
"Pherkad Minor" is the a common name for 11 UMi (5.01 mag) in Ursa Minor.
Concordance, Etymology, History
The name "Pherkad" has been used in recent times. It is derived from the singular form of the ind-A asterism name al-farqadan, "the Two Calves", for β and γ UMi. The name Pherkad was adopted by WGSN for the 3rd magnitude star γ UMi into the IAU-Catalog of Star Names in 2016.
The star 11 UMi ((HR 5714, HD 136726, HIP 74793) is a somewhat fainter (Vmag = 5.01) neighbour to γ UMi (Vmag = 3.00 mag), approximately 17 arcminutes away westward.
In the years after his 1801 discovery of the dwarf planet Ceres, Giuseppe Piazzi published the "Palermo Catalogue" containing positions for over 7000 stars, with a first edition in 1802 and a second edition in 1814 ("Praecipuarum Stellarum Inerrantium Positiones Mediae Ineunte Saeculo XIX. Ex Observationibus Habitis In Specula Panormitana Ab anno 1792 ad annum 1813") . In compiling this catalog, Piazzi included nearly 200 proper names for stars, some of which were new. Some names were borrowed from names of Arabian asterisms but with transliterated names, sometimes with descriptors, and assigned to individual stars. Piazzi labeled the brighter star γ UMi as "Pherkad ma." [i.e. "major"] and the fainter nearby star 11 UMi was labeled "Pherkad mi." [i.e. "minor"]. Shortly afterwards, Franz Xaver von Zach (1816) reproduced a list of the star names from Piazzi's Palermo Catalog ("Verzeichnifs der in Piazzi's neustem Stern-Catalog (Edit. Panormi 1814.) vorkommenden arabischen Stern-Namen"), writing out "Pherkad minor" for 11 UMi.
Despite their relative proximity, γ UMi and 11 UMi are unrelated. 11 UMi is a red giant star (spectral type K4III) approximately 411 light years away, while the brighter star γ UMi is a white giant (spectral type A2III) star at distance 493 light years.
In 2009, a candidate giant exoplanet was reported by Dollinger et al. orbiting 11 UMi with a ~1.4 year period. The minimum mass of the companion has been reported to be between about 10 and 15 Jupiter masses, and with an unknown inclination, the true mass of the companion may correspond to a brown dwarf rather than giant exoplanet.
Mythology
IAU Working Group on Star Names
The name Pherkad Minor was in sufficiently common use that it has been in SIMBAD for some time. IAU WGSN adopted the name for the IAU Catalog of Star Names in 202x.
Weblinks
Reference
- References (general)
- References (early modern)
- Ian Ridpath's website (Star Tales )
