Alpha Camelopardalis

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Template:Short description

Alpha Camelopardalis
Template:Location mark
Location of α Camelopardalis (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Camelopardalis
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 4.29[2]
Characteristics
Evolutionary stage Supergiant
Spectral type O9Ia[3]
U−B Template:Engvar −0.87[2]
B−V Template:Engvar +0.05[2]
R−I Template:Engvar 0.00[2]
Astrometry
Radial velocity (Rv)+6.1[4] km/s
Proper motion (μ) RA: +0.222 mas/yr[1]
Dec.: +7.198 mas/yr[1]
Parallax (π)0.5916±0.1333 mas[1]
Distanceapprox. Template:Rnd ly
(approx. Template:Rnd pc)
Absolute magnitude (MV)−7.1[5]
Details[6]
Mass37.6 Template:Solar mass
Radius32.5 Template:Solar radius
Luminosity676,000 Template:Solar luminosity
Surface gravity (log g)2.97 cgs
Temperature29,000 K
Rotational velocity (v sin i)100 km/s
Age~2[7] Myr
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist
Database references
SIMBADdata

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Alpha Camelopardalis is a blue hued star in the northern constellation of Camelopardalis. Its name is a Bayer designation that is Latinized from α Camelopardalis, and abbreviated Alpha Cam or α Cam. With an apparent visual magnitude of 4.3, it is visible to the naked eye as the third-brightest star in this not-very-prominent circumpolar constellation; the first and second-brightest stars being Beta Camelopardalis and CS Camelopardalis, respectively. It is the farthest constellational star, with a distance of approximately Template:Val from Earth based on parallax measurements.

Description

Alpha Camelopardalis has a stellar classification of O9 Ia, with the 'Ia' luminosity class indicating that it is an O-type luminous supergiant. It is a massive star with 37.6 times the mass of the Sun and 32.5 times the Sun's radius. The effective temperature of the outer envelope is 29,000 K; much hotter than the Sun's effective temperature of 5,778 K, giving it the characteristic blue hue of an O-type star.[8] It is emitting 676,000 times the luminosity of the Sun and is a weak X-ray emitter.[9] It has a high rate of spin, showing a projected rotational velocity of 100 km/s.[6]

Variations in the profiles of Alpha Camelopardalis' spectral lines are caused by fluctuations in the photosphere and stellar wind. This may be caused by non-radial pulsations. The absorption lines in the optical spectrum show radial velocity variations, although there is significant uncertainty about the period. Estimates range from a period as low as 0.36 days up to 2.93 days. The stellar wind from this star is not smooth and continuous, but instead shows a behavior indicating clumping at both large and small scales.[10] This star is losing mass rapidly through its stellar wind at a rate of approximately Template:Val solar masses per year,[5] or the equivalent of the mass of the Sun every 160,000 years.

In 1968, this star was classified as a spectroscopic binary, indicating that it has an orbiting stellar companion with a period of 3.68 days and an orbital eccentricity of 0.45. Subsequent studies refined the period to 3.24 days. However, in 2006 it was recognized that the changes in the spectrum were probably the result of changes in the atmosphere or stellar wind, so it is more likely a single star.[11] Speckle interferometry observations with the 3.67 m Advanced Electro Optical System Telescope at the Haleakala Observatory failed to detect a secondary component.[12]

In 1961, based on the criteria that the proper motion of this star indicates a space velocity of greater than 30 km/s,[13] Alpha Camelopardalis was suggested as a candidate runaway star that had been ejected from the cluster NGC 1502. This was based upon the kinematic properties of the star and cluster, as well as the location of this star at a high galactic latitude in an area otherwise lacking in stellar associations. Over the course of a million years, this star should have moved only 1.4° across the sky, while it was estimated as being only two million years old.[7]

Runaway stars such as this with a stellar wind that is moving at supersonic velocity through the interstellar medium have their wind confined by a bow shock due to ram pressure. The dust in this bow shock can be detected using an infrared telescope.[14] Just such a bow shock was observed with NASA's Wide-field Infrared Survey Explorer, or WISE. The star is traveling with a peculiar velocity of somewhere between 680 and 4,200 kilometers per second: between 1.5 and 9.4 million mph.[15]

Chinese name

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Right Wall of Purple Forbidden Enclosure, refers to an asterism consisting of α Camelopardalis, α Draconis, κ Draconis, λ Draconis, 24 Ursae Majoris, 43 Camelopardalis and BK Camelopardalis.[16] Consequently, the Chinese name for α Camelopardalis itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx.),[17] representing Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Second Imperial Guard.[18][19] 少衛 (Shǎowèi) is westernized into Shaou Wei by R. H. Allen, the meaning is "Minor Guard", but it is not clearly designated.[19]

References

Template:Reflist

External links

Template:Stars of Camelopardalis Template:Sky

  1. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named GaiaDR3
  2. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named ducati
  3. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named gosss
  4. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named wilson1953
  5. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named aaa385_479
  6. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named repolust
  7. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named bain15_265
  8. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named csiro
  9. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named aj72_1019
  10. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named aaa457_3_987
  11. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named apj655_1_473
  12. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named aj136_2_554
  13. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named ajss64_545
  14. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named aj113_780
  15. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named calvin20110311
  16. ↑ 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.
  17. ↑ Template:In lang AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 11 日 Template:Webarchive
  18. ↑ English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name Template:Webarchive, Hong Kong Space Museum. Accessed on line November 23, 2010
  19. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named allen1899
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