Nu Ursae Majoris

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Template:Short description

Nu Ursae Majoris
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Location of ν Ursae Majoris (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Ursa Major
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) +3.490[2]
Characteristics
Spectral type K3 III[3]
U−B Template:Engvar +1.550[2]
B−V Template:Engvar +1.400[2]
Astrometry
Radial velocity (Rv)-9.63 ± 0.38[4] km/s
Proper motion (μ) RA: Script error: No such module "val". mas/yr[1]
Dec.: Script error: No such module "val". mas/yr[1]
Parallax (π)8.17±0.17 mas[5]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)−2.47 ± 0.16[6]
Details
MassScript error: No such module "val".[7] Template:Solar mass
RadiusScript error: No such module "val".[7] Template:Solar radius
LuminosityScript error: No such module "val".[7] Template:Solar luminosity
Surface gravity (log g)1.89[6] cgs
TemperatureScript error: No such module "val".[7] K
Metallicity [Fe/H]–0.04[6] dex
Rotational velocity (v sin i)10[8] km/s
AgeScript error: No such module "val".[7] Myr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Alula Borealis, ν Ursae Majoris, ν UMa, Nu UMa, 54 Ursae Majoris, BD+33 2098, CCDM J11185+3306A, FK5 425, GC 15547, HD 98262, HIP 55219, HR 4377, IDS 11131+3338 A, PPM 75790, SAO 62486, WDS J11185+3306A [9]
Database references
SIMBADdata

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Nu Ursae Majoris (ν Ursae Majoris, abbreviated Nu UMa, ν UMa), formally named Alula Borealis Template:IPAc-en,[10][11] is a double star in the northern circumpolar constellation of Ursa Major. At an apparent visual magnitude of +3.490,[2] it is bright enough to be seen with the naked eye. Based upon parallax measurements, the distance to ν Ursae Majoris is about Script error: No such module "convert"..[5] At such distance, its apparent brightness is diminished by 0.48 magnitudes due to interveining gas and dust.[7]

This is a giant star with a stellar classification of K3 III.[3] Being 200 million years old, it has expanded to about 60 times the radius of the Sun and is radiating 1240 times the Sun's luminosity. The effective temperature of the outer envelope is 4,422 K;[7] cool enough to give it an orange hue typical of a K-type star.[12] It has a 10th-magnitude optical companion at an angular separation of 7.1 arcseconds.

Nomenclature

ν Ursae Majoris (Latinised to Nu Ursae Majoris) is the star's Bayer designation.

It also bore the traditional name of Alula Borealis.[13] Alula (shared with Xi Ursae Majoris) comes from the Arabic phrase Script error: No such module "lang". 'the First Spring'.[14] and Borealis is Latin for 'northern'. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[15] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[16] included a table of the first two batches of names approved by the WGSN; which included Alula Borealis for this star.

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Three Steps, refers to an asterism consisting of Nu Ursae Majoris, Iota Ursae Majoris, Kappa Ursae Majoris, Lambda Ursae Majoris, Mu Ursae Majoris, and Xi Ursae Majoris. Consequently, the Chinese name for Nu Ursae Majoris itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx).[17]

References

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  13. Piazzi, G., The Palermo Catalogue, Palermo, 1814.
  14. Richard Hinckley Allen :Star Names — Their Lore and Meaning - Ursa Major, the Greater Bear
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  16. Script error: No such module "citation/CS1".
  17. Template:In lang (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 21 日 Template:Webarchive

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Template:Stars of Ursa Major