Mimosa (star)

Coordinates: Sky map 12h 47m 43.26877s, −59° 41′ 19.5792″
Source: Wikipedia, the free encyclopedia.
Mimosa
Location of Mimosa (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Crux
Pronunciation
 /mɪˈmoʊsə/[1]
Right ascension 12h 47m 43.26877s[2]
Declination −59° 41′ 19.5792″[2]
Apparent magnitude (V) 1.25[3] (1.23 - 1.31)[4]
Characteristics
Spectral type B0.5 III[5] / B2V[6]
U−B color index −0.98[3]
B−V color index −0.23[3]
Variable type β Cep[5]
Distance
280 ± 20 ly
(85 ± 7 pc)
Absolute magnitude (MV)−3.92[8]
Argument of periastron
(ω)
(secondary)		293±9°
Details
A
Myr
B
Mass10[6] M☉
HR 4853, SAO 240259[11]
Database references
SIMBADdata

Mimosa is the second-brightest object in the southern

Southern Cross. It is a binary star or a possible triple star system
.

Nomenclature

β Crucis (Latinised to Beta Crucis) is the system's

precession of equinoxes, and these civilizations regarded it as part of the constellation of Centaurus.[12]

It bore the traditional names Mimosa and the historical name Becrux /ˈbeɪkrʌks/.[13] Mimosa, which is derived from the Latin for 'actor', may come from the flower of the same name.[14] Becrux is a modern contraction of the Bayer designation.[10] In 2016, the International Astronomical Union organized a 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 Mimosa for this star.

In

Gamma Crucis, and Delta Crucis.[17] Consequently, Mimosa itself is known as 十字架三 (Shí Zì Jià sān, English: the Third Star of Cross.).[18]

Stellar system

The constellation Crux

Based on

Astronomical Units.[6] The system is only 8 to 11 million years old.[5]

The primary, β Crucis A, is a massive star with about 16 times the Sun's mass. The projected rotational velocity of this star is about 35 km s−1. However, the orbital plane of the pair is only about 10°, which probably means the inclination of the star's pole is also likely to be low. This suggests that the azimuthal rotational velocity is quite high, at about 120 km s−1. With a radius of about 8.4 times the radius of the Sun, this would mean the star has a rotational period of only about 3.6 days.[5]

A light curve for Beta Crucis, plotted from TESS data[20]

β Crucis A is a known

luminosity class of 'III' indicating that this is a giant star that has exhausted the supply of hydrogen at its core. The high temperature of the star's outer envelope is what gives the star the blue-white hue that is characteristic of B-type stars.[22] It is generating a strong stellar wind and is losing about 10−8 M☉ per year, or the equivalent of the mass of the Sun every 100 million years. The wind is leaving the system with a velocity of 2,000 km s−1 or more.[5]

The secondary, β Crucis B, may be a main sequence star with a stellar class of B2.

arcseconds, are likely optical companions that are not physically associated with the system. The β Crucis system may be a member of the Lower Centaurus–Crux sub-group of the Scorpius–Centaurus association.[23] This is a stellar association of stars that share a common origin.[5]

In culture

Mimosa is represented in the flags of

Southern Cross.[5] It is also featured in the flag of Brazil, along with 26 other stars, each of which represents a state. Mimosa represents the State of Rio de Janeiro.[24]

A vessel named MV Becrux is used to export live cattle from Australia to customers in Asia. An episode dedicated to the vessel features in the television documentary series Mighty Ships.[25]

References

  1. ^ a b "IAU Catalog of Star Names". Retrieved 28 July 2016.
  2. ^
    S2CID 18759600
  3. ^
    Bibcode:1966CoLPL...4...99J
  4. Bibcode:2009yCat....102025S
    .
  5. ^
    S2CID 2924933
  6. ^
    Bibcode:1998A&A...329..137A
  7. Bibcode:1967IAUS...30...57E
    .
  8. S2CID 54222753
  9. Bibcode:1994A&A...282..867K
  10. ^
    Bibcode:1991bsc..book.....H
    .
  11. ^ "HD 93521", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-05-07.
  12. ISBN 978-0-86243-952-1
  13. ^ "Audio Pronunciation Guide". Starry Night Education. Simulation Curriculum Corp. 2009. Retrieved 26 Apr 2019.
  14. ^ "MIMOSA (Beta Crucis)", Stars, university of Illinois, archived from the original on 2005-12-22, retrieved 2011-12-30
  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. Bibcode:1957Obs....77..200H
  20. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  21. S2CID 244953278
  22. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2012-03-18, retrieved 2012-01-16
  23. S2CID 54510608
    .
  24. ^ "Astronomy of the Brazilian Flag". FOTW Flags Of The World website.
  25. ^ "Mighty Ships". DiscoveryHD.ca. CTV Global Media. Archived from the original on 15 September 2008. Retrieved 25 November 2013.{{cite web}}: CS1 maint: unfit URL (link)

External links


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