BK Camelopardalis

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BK Camelopardalis
Camelopardalis constellation map.svg
Red circle.svg
Location of BK Camelopardalis (circled)
Observation data
Epoch J2000       Equinox J2000
Constellation Camelopardalis
Right ascension 03h 19m 59.27222s [1]
Declination +65° 39′ 08.2519″ [1]
Apparent magnitude  (V)4.74 [2] (4.76 - 4.90) [3]
Characteristics
Evolutionary stage main sequence [4]
Spectral type B2.5 Vne [5]
U−B color index −0.77 [6]
B−V color index −0.108±0.002 [2]
R−I color index −0.13 [6]
Variable type Be star [3]
Astrometry
Radial velocity (Rv)−3.4±3.5 [2]  km/s
Proper motion (μ)RA: +10.506 [1]   mas/yr
Dec.: −14.677 [1]   mas/yr
Parallax (π)6.0704 ± 0.3539  mas [1]
Distance 540 ± 30  ly
(165 ± 10  pc)
Absolute magnitude  (MV)−2.07 [2]
Details
Mass 7.5 [5]   M☉
Radius 4.0 [7]   R☉
Luminosity 1080.69 [2]   L☉
Surface gravity (log g)4.20 [4]   cgs
Temperature 18,720 [4]   K
Rotational velocity (v sin i)328 [4]  km/s
Age 31.6 [5]   Myr
Other designations
BK Cam, BD+65°340, HD  20336, HIP  15520, HR  985, SAO  12704 [8]
Database references
SIMBAD data

BK Camelopardalis is a variable star in the northern circumpolar constellation of Camelopardalis, near the constellation border with Cassiopeia. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude that fluctuates around 4.74. [2] The star is located approximately 540  light years away from the Sun based on parallax. [1] It is a proposed member of the Cassiopeia–Taurus group of co-moving stars. [9]

Contents

Description

This is a main sequence Be star [4] with a stellar classification of B2.5 Vne, [5] where the 'n' suffix indicates "nebulous" (broad) lines due to rapid rotation. The presence of emission lines in the spectrum has been known since at least 1895. [10] Spectrograms of the star have been taken since 1905, providing a long history of its cycles of variation. [11] It ranges in brightness from a peak of 4.76 down to 4.90. [3]

BK Camelopardalis is 32 [5]  million years old and is spinning with a projected rotational velocity of 328 km/s. [4] It has 7.5 [5] times the mass of the Sun and four [7] times the Sun's radius. The star is radiating 1,081 [2] times the luminosity of the Sun from its photosphere at an effective temperature of 18,720 K. [4]

This star lies at the center of a circular, disk-like structure spanning 1.4°, which may be a "magnetic funnel-like structure" that is emitting in the radio band. Neutral hydrogen along the trajectory of this star has been found to be deficient, which may be the result of ionizing radiation from the star. [12]

Two stars have been resolved close to BK Camelopardalis. The first, designated Ab, is separated by about 0.13 arcseconds. If it is physically associated with BK Camelopardalis, it would have an orbital period of several decades. The second star is designated as B but is likely an optical pair with the central BK Camelopardalis; that is, a chance alignment. [13]

Chinese name

In Chinese, 紫微右垣 (Zǐ Wēi Yòu Yuán), meaning Right Wall of Purple Forbidden Enclosure , refers to an asterism consisting of BK Camelopardalis, α Draconis, κ Draconis, λ Draconis, 24 Ursae Majoris, 43 Camelopardalis and α Camelopardalis. [14] Consequently, BK Camelopardalis itself is known as 紫微右垣七 (Zǐ Wēi Yòu Yuán qī, English: the Seventh Star of Right Wall of Purple Forbidden Enclosure.) representing 上丞 (Shǎngchéng), meaning First Prime Minister. [15]

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Alpha Camelopardalis, Latinized from α Camelopardalis, is a star in the northern constellation of Camelopardalis. With an apparent visual magnitude of 4.3, it is 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 6,000 light-years from Earth based on parallax measurements.

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<span class="mw-page-title-main">CL Draconis</span> Star in the constellation Draco

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68 Draconis is the Flamsteed designation for a star in the northern circumpolar constellation of Draco. It has an apparent visual magnitude of 5.69, so, according to the Bortle scale, it is faintly visible to the naked eye from suburban skies at night. Measurements made with the Gaia spacecraft show an annual parallax shift of 0.0209232″, which is equivalent to a distance of around 156 ly (48 pc) from the Sun. It is moving closer to the Earth with a heliocentric radial velocity of –14.6 km/s. The star has a relatively high proper motion, traversing the celestial sphere at a rate of 0.150″ per year.

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<span class="mw-page-title-main">HD 27022</span> Star in the constellation Camelopardalis

HD 27022, also known as HR 1327, is a star located in the northern circumpolar constellation Camelopardalis. The object has also been designated as 20 H. Camelopardalis, but is not commonly used in modern times. It has an apparent magnitude of 5.27, allowing it to be faintly visible to the naked eye. Based on parallax measurements from Gaia DR3, the star has been estimated to be 347 light years away. It appears to be approaching the Solar System, having a heliocentric radial velocity of −19.5 km/s.

EK Eridani is a single variable star in the equatorial constellation of Eridanus. It has the designation HR 1362 from the Bright Star Catalogue; EK Eridani is the variable star designation, abbreviated EK Eri. This star is dimly visible to the naked eye with a brightness that fluctuates around 6.15. Based on parallax measurements, it is located at a distance of 209 light years from the Sun. The star is drifting further away with a heliocentric radial velocity of 6.9 km/s.

References

  1. 1 2 3 4 5 6 Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics . 616. A1. arXiv: 1804.09365 . Bibcode: 2018A&A...616A...1G . doi: 10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR.
  2. 1 2 3 4 5 6 7 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv: 1108.4971 . Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID   119257644.
  3. 1 2 3 Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID   125853869.
  4. 1 2 3 4 5 6 7 Zorec, J.; et al. (2005). "On the evolutionary status of Be stars. I. Field Be stars near the Sun". Astronomy and Astrophysics. 441 (1): 235–248. arXiv: astro-ph/0509119 . Bibcode:2005A&A...441..235Z. doi:10.1051/0004-6361:20053051. S2CID   17592657.
  5. 1 2 3 4 5 6 Tetzlaff, N.; et al. (2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv: 1007.4883 . Bibcode:2011MNRAS.410..190T. doi: 10.1111/j.1365-2966.2010.17434.x . S2CID   118629873.
  6. 1 2 Ducati, J. R. (2002). "Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  7. 1 2 Underhill, A. B.; et al. (1979). "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars". Monthly Notices of the Royal Astronomical Society. 189 (3): 601. Bibcode:1979MNRAS.189..601U. doi: 10.1093/mnras/189.3.601 .
  8. ↑ "BK Cam". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-08-12.
  9. ↑ de Zeeuw, P. T.; et al. (January 1999), "A HIPPARCOS Census of the Nearby OB Associations", The Astronomical Journal, 117 (1): 354–399, arXiv: astro-ph/9809227 , Bibcode:1999AJ....117..354D, doi:10.1086/300682, S2CID   16098861
  10. ↑ Campbell, W. W. (October 1895). "Stars whose spectra contain both bright and dark hydrogen lines". Astrophysical Journal. 2: 177−183. Bibcode:1895ApJ.....2..177C. doi: 10.1086/140127 .
  11. ↑ McLaughlin, Dean B. (May 1963). "The be Spectrum Variable HD 20336". Astrophysical Journal. 137: 1085. Bibcode:1963ApJ...137.1085M. doi:10.1086/147587.
  12. ↑ Haverkorn, M.; et al. (June 2003). "Multi-frequency polarimetry of the Galactic radio background around 350 MHz. II. A region in Horologium around l = 137degr , b = 7degr". Astronomy and Astrophysics. 404: 233−247. arXiv: astro-ph/0304087 . Bibcode:2003A&A...404..233H. doi: 10.1051/0004-6361:20030530 .
  13. ↑ Hutter, D. J.; Tycner, C.; Zavala, R. T.; Benson, J. A.; Hummel, C. A.; Zirm, H. (2021). "Surveying the Bright Stars by Optical Interferometry. III. A Magnitude-limited Multiplicity Survey of Classical Be Stars". The Astrophysical Journal Supplement Series. 257 (2): 69. arXiv: 2109.06839 . Bibcode:2021ApJS..257...69H. doi: 10.3847/1538-4365/ac23cb . S2CID   237503492.
  14. ↑ (in Chinese)中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN   978-986-7332-25-7.
  15. ↑ English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name Archived August 10, 2010, at the Wayback Machine , Hong Kong Space Museum. Accessed on line November 23, 2010.
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