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BE Camelopardalis

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BE Camelopardalis
Location of BE Camelopardalis (circled in red)
Observation data
Epoch J2000      Equinox J2000
Constellation Camelopardalis
Right ascension 03h 49m 31.27755s[1]
Declination +65° 31′ 33.5258″[1]
Apparent magnitude (V) 4.39[2] (4.35 - 4.48)[3]
Characteristics
Evolutionary stage asymptotic giant branch[4]
Spectral type M2 II[5]
B−V color index 1.870±0.029[2]
Variable type Lc[3]
Astrometry
Radial velocity (Rv)−1.70±1.47[2] km/s
Proper motion (μ) RA: +0.319 mas/yr[1]
Dec.: −15.593 mas/yr[1]
Parallax (π)3.3288±0.1874 mas[1]
Distance958+53
−51 ly
(293.7+16.4
−15.5 pc)[6]
Absolute magnitude (MV)−2.51[2]
Details
Mass2.93[7] M☉
Radius250[8] R☉
Luminosity10,600[8] L☉
Temperature3,660[8] K
Other designations
Custos, BE Cam, BD+65°369, HD 23475, HIP 17884, HR 1155, SAO 12916[9]
Database references
SIMBADdata

BE Camelopardalis, also named Custos,[10] is a solitary[11] variable star in the northern circumpolar constellation of Camelopardalis. It is visible to the naked eye as a faint, red-hued point of light with an apparent visual magnitude that fluctuates around 4.39.[2] The star is located roughly 960 light years away.[6]

A light curve for BE Camelopardalis, plotted from Hipparcos data[12]

This object is an M-type bright giant with a stellar classification of M2 II,[5] and is currently on the asymptotic giant branch. In 1928, Joel Stebbins and Charles Morse Huffer announced that the star, then called HR 1155, is a variable star, based on observations made at Washburn Observatory.[13] It was given its variable star designation, BE Camelopardalis, in 1977.[14] It is classified as an irregular variable of subtype Lc and its brightness varies from magnitude +4.35 down to +4.48.[3] Having exhausted the supply of hydrogen at its core, the star has expanded to around 250[8] times the Sun's radius. It has 2.9[7] times the Sun's mass and is radiating over 10,000 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 3,660 K.[8]

This star was part of the now-obsolete constellation Custos Messium, the Harvest Keeper, which was named as a pun on Charles Messier. The IAU Working Group on Star Names approved the name Custos for this star on 25 December 2025, after the obsolete constellation, and it is now so entered in the IAU Catalog of Star Names.[10] The brightest star of Custos Messium, 50 Cassiopeiae,[15] was given the proper name Gang after a Chinese constellation.[10]

References

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  1. ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b c d e 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. ^ a b c 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. ^ Eggen, Olin J. (July 1992). "Asymptotic giant branch stars near the sun". Astronomical Journal. 104 (1): 275–313. Bibcode:1992AJ....104..275E. doi:10.1086/116239.
  5. ^ a b Levesque, Emily M.; et al. (August 2005). "The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not As Cool As We Thought". The Astrophysical Journal. 628 (2): 973–985. arXiv:astro-ph/0504337. Bibcode:2005ApJ...628..973L. doi:10.1086/430901. S2CID 15109583.
  6. ^ a b Bailer-Jones, C. A. L.; Rybizki, J.; Fouesneau, M.; Demleitner, M.; Andrae, R. (2021-03-01). "Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3". The Astronomical Journal. 161 (3): 147. arXiv:2012.05220. Bibcode:2021AJ....161..147B. doi:10.3847/1538-3881/abd806. ISSN 0004-6256. Data about this star can be seen here.
  7. ^ a b Hohle, M. M.; et al. (2010). "Masses and luminosities of O- and B-type stars and red supergiants". Astronomische Nachrichten. 331 (4): 349. arXiv:1003.2335. Bibcode:2010AN....331..349H. doi:10.1002/asna.200911355. S2CID 111387483.
  8. ^ a b c d e Healy, Sarah; Horiuchi, Shunsaku; Molla, Marta Colomer; Milisavljevic, Dan; Tseng, Jeff; Bergin, Faith; Weil, Kathryn; Tanaka, Masaomi (2024-03-23). "Red Supergiant Candidates for Multimessenger Monitoring of the Next Galactic Supernova". Monthly Notices of the Royal Astronomical Society. 529 (4): 3630–3650. arXiv:2307.08785. Bibcode:2024MNRAS.529.3630H. doi:10.1093/mnras/stae738. ISSN 0035-8711.
  9. ^ "BE Cam". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-08-12.
  10. ^ a b c "IAU Catalog of Star Names". Retrieved 28 December 2025.
  11. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
  12. ^ "Hipparcos Tools Interactive Data Access". Hipparcos. ESA. Retrieved 8 December 2021.
  13. ^ Stebbins, Joel; Huffer, C. M. (1928). "The Constancy of the Light of Red Stars". Publications of the Washburn Observatory. 15: 137–174. Bibcode:1928PWasO..15..137S. Retrieved 5 December 2024.
  14. ^ Kukarkin, B. V.; Kholopov, P. N.; Fedorovich, V. P.; Kireyeva, N. N.; Kukarkina, N. P.; Medvedeva, G. I.; Perova, N. B. (March 1977). "62nd Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 1248: 1. Bibcode:1977IBVS.1248....1K. Retrieved 29 December 2024.
  15. ^ Ridpath, Ian. "Star Tales – Custos Messium". Retrieved 28 December 2025.