Alpha Lupi

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Template:Short description

Alpha Lupi
Template:Location mark
Location of α Lupi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Lupus
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 2.30[2] (2.29 - 2.34[3])
Characteristics
Spectral type B1.5 III[4]
U−B Template:Engvar −0.88[2]
B−V Template:Engvar −0.20[2]
Variable type β Cep[3]
Astrometry
Radial velocity (Rv)Script error: No such module "val".[5] km/s
Proper motion (μ) RA: −20.94[1] mas/yr
Dec.: −23.67[1] mas/yr
Parallax (π)7.02±0.17 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)−4.3[6]
Details
MassScript error: No such module "val".[7] Template:Solar mass
RadiusTemplate:Solar radius calculator[8]Template:Efn Template:Solar radius
LuminosityScript error: No such module "val".[8] Template:Solar luminosity
Surface gravity (log g)3.46[6] cgs
Temperature24,550[8] K
Metallicity [Fe/H]0.04[9] dex
Rotational velocity (v sin i)9.5[8] km/s
Age16–20[5] Myr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Uridim, α Lup, CD−46°9501, FK5 541, HD 129056, HIP 71860, HR 5469, SAO 225128[10]
Database references
SIMBADdata

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Alpha Lupi (α Lupi, α Lup), also named Uridim,[11] is a blue giant star, and the brightest star in the southern constellation of Lupus. According to the Bortle Dark-Sky Scale, its apparent visual magnitude of 2.3[2] makes it readily visible to the naked eye even from highly light-polluted locales. Based upon parallax measurements made during the Hipparcos mission,[12] the star is around Script error: No such module "convert". from the Solar System.[1] It is one of the nearest supernova candidates.[13]

Characteristics

File:AlphaLupLightCurve.png
A light curve for Alpha Lupi, plotted from Hipparcos data[14]

Alpha Lupi is a giant star with a stellar classification of B1.5 III.[4] It has about ten times the mass of the Sun[7] yet is radiating 18,000 times the Sun's luminosity. The outer atmosphere has an effective temperature of 24,550 K,[8] which gives it the blue-white glow of a B-type star. In 1956 it was identified as a Beta Cephei variable by Bernard Pagel and colleagues,[15] which means it undergoes periodic changes in luminosity because of pulsations in the atmosphere. The variability period is 0.29585 days,[9] or just over 7 hours, 6 minutes. The magnitude varies by about 0.05 magnitudes, or about 5% of its brightness. A 14th magnitude star situated 26" from Alpha Lupi is listed as a companion in double star catalogues.[16]

This star is a proper motion member of the Upper Centaurus–Lupus sub-group in the Scorpius–Centaurus OB association, the nearest such co-moving association of massive stars to the Sun.[6] This is a gravitationally unbound stellar association with an estimated age of 16–20 million years. The association is also the source of a bubble of hot gas that contains the Sun, known as the Local Bubble.[5]

Visibility

Visible from the Southern Hemisphere for much of the year, it can also be viewed for a shorter season from the northern tropics and from parts of the northern subtropical latitudes.

Nomenclature

α Lupi (Latinised to Alpha Lupi) is the star's Bayer designation.

In Chinese, Kekouan Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Imperial Guards, refers to an asterism consisting of α Lupi, γ Lupi, δ Lupi, κ Centauri, β Lupi, λ Lupi, ε Lupi, μ Lup, π Lupi, and ο Lupi.[17] Consequently, the Chinese name for α Lupi itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx.).[18]

R. H. Allen described this star as having the Chinese name Yang Mun or Men (南門), meaning "the South Gate", in his work Star-Names and their Meanings.[19] In Chinese astronomy, 南門 is located in Horn mansion and consisted of α and ε Centauri. It was referred to as Yang Mun, meaning "the south Gate". Allen also suggested that the Babylonian name for the star was "Kakkab Su-gub Gud-Elim" (Star Left Hand of the Horned Bull).[19]

The Sumerian name for the constellation Lupus was UR.IDIM, later alternatively written "Uridimmu" in the Akkadian language. The IAU Working Group on Star Names approved the name Uridim for this star on 12 September 2024 and it is now so entered in the IAU Catalog of Star Names.[11]

Notes

Template:Notelist

References

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  1. ↑ a b c d e f Script error: No such module "citation/CS1".
  2. ↑ a b c d Script error: No such module "citation/CS1".
  3. ↑ a b Script error: No such module "citation/CS1".
  4. ↑ a b Script error: No such module "citation/CS1".
  5. ↑ a b c Script error: No such module "citation/CS1".
  6. ↑ a b c Script error: No such module "citation/CS1".
  7. ↑ a b Script error: No such module "citation/CS1".
  8. ↑ a b c d e Script error: No such module "Citation/CS1".
  9. ↑ a b Script error: No such module "citation/CS1".
  10. ↑ Script error: No such module "citation/CS1".
  11. ↑ a b Script error: No such module "citation/CS1".
  12. ↑ Script error: No such module "citation/CS1".
  13. ↑ Script error: No such module "citation/CS1".
  14. ↑ Script error: No such module "citation/CS1".
  15. ↑ Script error: No such module "citation/CS1".
  16. ↑ Script error: No such module "citation/CS1".
  17. ↑ Template:In lang 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, Template:ISBN
  18. ↑ Template:In lang 香港太空館 - 研究資源 - 亮星中英對照表 Template:Webarchive, Hong Kong Space Museum. Accessed on line November 23, 2010]
  19. ↑ a b Script error: No such module "citation/CS1".

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Template:Stars of Lupus

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