Astronomy:BO Carinae

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Short description: Star in the constellation Carina
BO Carinae
Carina Nebula by ESO.jpg
BO Carinae is the brightest red star, towards upper left, in this image of the Carina Nebula.
Credit: ESO
Observation data
Equinox J2000.0]] (ICRS)
Constellation Carina
Right ascension  10h 46m 00.53s
Declination 59° 29′ 19.5″
Apparent magnitude (V) 7.18 - 8.50[1]
Characteristics
Spectral type M4 Ib[1]
Variable type Lc[1]
Astrometry
Proper motion (μ) RA: −7.334±0.027[2] mas/yr
Dec.: −1.420±0.028[2] mas/yr
Parallax (π)0.6020 ± 0.0259[2] mas
Distance5,400 ± 200 ly
(1,660 ± 70 pc)
Details
Radius439[3] R
Luminosity26,000 - 27,000[3] L
Temperature3,535±170[3] K
Other designations
BO Car, IDS 10419-5858, IRAS 10438-5913, 2MASS J10455065-5929193, AAVSO 1042-58, SAO 238447, CD-58 3547, HD 93420
Database references
SIMBADdata

BO Carinae, also known as HD 93420, is an irregular variable star in the constellation Carina.

BO Car has a maximum apparent magnitude of +7.18. Its distance and membership is uncertain, but its possible membership to the star cluster Trumpler 15 allows a distance estimate of approximately 2,500 parsecs (8,150 light-years).[4][5] The Gaia Data Release 2 parallax of 0.73±0.08 mas suggests a closer distance, but the value is considered unreliable due to excess astrometric noise.[6]

BO Car is a red supergiant of spectral type M4Ib with an effective temperature of 3,525 K, a radius of 439 solar radii. Its bolometric luminosity is 26,000 L.[7] Mass-loss is on the order of 0.3×10−9 solar masses per year.[5]

An I band (near infrared) light curve for BO Carinae, plotted from ASAS data[8]

Billed as an irregular variable like TZ Cassiopeiae or V528 Carinae; its apparent brightness fluctuates between magnitude +7.18 and +8.50 without clear periodicity.[1][9] Some observers have found BO Car not to be variable,[10] but more extensive studies find small amplitude variations with a possible period of 145 days.[11]

Multiple star catalogues list an 11th-magnitude star as a companion to BO Car. The separation was 14.2 in 2015, and slowly increasing.[12] The companion is a distant blue giant.[13]

See also

References

  1. 1.0 1.1 1.2 1.3 Samus, N. N. et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1. Bibcode2009yCat....102025S. 
  2. 2.0 2.1 2.2 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  3. 3.0 3.1 3.2 Messineo, M.; Brown, A. G. A. (2019). "A Catalog of Known Galactic K-M Stars of Class I Candidate Red Supergiants in Gaia DR2". The Astronomical Journal 158 (1): 20. doi:10.3847/1538-3881/ab1cbd. Bibcode2019AJ....158...20M. 
  4. Tapia, Mauricio; Roth, Miguel; Vázquez, Rubén A.; Feinstein, Alejandro (2003). "Imaging study of NGC 3372, the Carina nebula - I. UBVRIJHK photometry of Tr 14, Tr 15, Tr 16 and Car I". Monthly Notices of the Royal Astronomical Society 339 (1): 44–62. doi:10.1046/j.1365-8711.2003.06186.x. Bibcode2003MNRAS.339...44T. 
  5. 5.0 5.1 Josselin, E.; Blommaert, J. A. D. L.; Groenewegen, M. A. T.; Omont, A.; Li, F. L. (2000). "Observational investigation of mass loss of M supergiants". Astronomy and Astrophysics 357: 225–232. Bibcode2000A&A...357..225J. 
  6. Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  7. Cite error: Invalid <ref> tag; no text was provided for refs named rg
  8. "ASAS All Star Catalogue". The All Sky Automated Survey. http://www.astrouw.edu.pl/asas/?page=aasc. 
  9. Chatys, Filip W.; Bedding, Timothy R.; Murphy, Simon J.; Kiss, László L.; Dobie, Dougal; Grindlay, Jonathan E. (2019). "The period-luminosity relation of red supergiants with Gaia DR2". Monthly Notices of the Royal Astronomical Society 487 (4): 4832. doi:10.1093/mnras/stz1584. Bibcode2019MNRAS.487.4832C. 
  10. Percy, John R.; Sato, Hiromitsu (2009-02-01). "Long Secondary Periods in Pulsating Red Supergiant Stars". Journal of the Royal Astronomical Society of Canada 103 (1): 11. ISSN 0035-872X. Bibcode2009JRASC.103...11P. 
  11. Percy, J. R. (2020). "Period Analysis of All-Sky Automated Survey for Supernovae (ASAS-SN) Data on a Sample of "Irregular" Pulsating Red Giants". Journal of the American Association of Variable Star Observers (Jaavso) 48 (1): 50. Bibcode2020JAVSO..48...50P. 
  12. Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal 122 (6): 3466. doi:10.1086/323920. Bibcode2001AJ....122.3466M. 
  13. Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.