Beta Canis Minoris

Source: Wikipedia, the free encyclopedia.
Beta Canis Minoris

Position of Beta Canis Minoris
Observation data
Epoch J2000      Equinox J2000
Constellation Canis Minor
Right ascension 07h 27m 09.04174s[1]
Declination +08° 17′ 21.5368″[1]
Apparent magnitude (V) 2.84–2.92[2]
Characteristics
Spectral type B8 Ve[3]
U−B color index −0.28[4]
B−V color index −0.09[4]
Variable type γ Cas[2] + SPBe[3]
Distance
160 ± 10 ly
(49 ± 3 pc)
Absolute magnitude (MV)−0.59[7]
Details
Myr
HIP 36188, HR 2845, IRAS 07244+0823, SAO 115456[11]
Database references
SIMBADdata

Beta Canis Minoris (β Canis Minoris, abbreviated Beta CMi, β CMi), also named Gomeisa /ɡɒˈmaɪzə/,[12][13] is a star in the constellation of Canis Minor. In the night sky it is notable for its proximity to the prominent star Procyon.

Nomenclature

β Canis Minoris (Latinised to Beta Canis Minoris) is the star's Bayer designation.

The traditional name Gomeisa comes from the

Working Group on Star Names (WGSN)[15] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016[16]
included a table of the first two batches of names approved by the WGSN; which included Gomeisa for this star.

In Chinese, 南河 (Nán Hé), meaning South River, refers to an asterism consisting of β Canis Minoris, Procyon and Epsilon Canis Minoris.[17] Consequently, β Canis Minoris itself is known as 南河二 (Nán Hé èr, English: the Second Star of South River).[18]

Properties

From

rotational velocity along the star's equator. The actual rotation rate may be about once per day.[14]

The

circumstellar disk made of gaseous material ejected from the star. This hot, gaseous disk is about three times the radius of the star.[3]

Variability

A broadband optical light curve for Beta Canis Minoris, adapted from Saio et al. (2007)[3]

β Canis Minoris has long been suspected of variability,

γ Cassiopeiae variable in the General Catalogue of Variable Stars. A number of studies have found no variation at all.[21] While it shows little variation in brightness, it does display changes in the hydrogen emission coming from the gaseous disk but even those are less pronounced than in many other Be stars.[22]

Examination with the Canadian

frequencies, with the dominant frequencies being 3.257 and 3.282 cycles per day. As such, it belongs to a class called slowly pulsating B-type (SPB) stars. Be stars that show these types of pulsation have been dubbed SPBe stars.[3]

Possible companion

It is likely that Beta Canis Minoris is a close binary with a 170-day, eccentric orbit. The companion would have about 42% of the Sun's mass. The nature of the companion is unknown, but it is speculated that it could be a subdwarf O star remaining after binary interactions that spun up the Be primary. If confirmed, this would make it a member of the very rare Phi Persei Be+sdO-type systems.[22]

References

  1. ^
    S2CID 18759600
    .
  2. ^
    Bibcode:2009yCat....102025S
    .
  3. ^
    S2CID 118836002
  4. ^
    Bibcode:1966CoLPL...4...99J
  5. Bibcode:1953GCRV..C......0W
    .
  6. ^
    doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR
    .
  7. S2CID 119257644
    .
  8. ^
    S2CID 12694072
  9. ^
    doi:10.1086/340590
  10. S2CID 119217803
  11. Centre de Données astronomiques de Strasbourg
    , retrieved 2012-01-09
  12. ISBN 978-1-931559-44-7
    .
  13. ^ "IAU Catalog of Star Names". Retrieved 28 July 2016.
  14. ^
    University of Illinois
    , retrieved 2012-01-09
  15. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  16. ^ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016.
  17. ISBN 978-986-7332-25-7
    .
  18. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2011-01-30 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  19. Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original
    on 2012-03-18, retrieved 2012-01-16
  20. doi:10.1093/mnras/96.3.258
    .
  21. Bibcode:1982IBVS.2123....1B
    .
  22. ^
    S2CID 119370197
    .
Retrieved from "https://en.wikipedia.org/w/index.php?title=Beta_Canis_Minoris&oldid=1186860237"