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Mimosa (star)

April 10, 2024

Mimosa is the second-brightest object in the southern constellation of Crux (after Acrux), and the 20th-brightest star in the night sky. It has the Bayer designation β Crucis, which is Latinised to Beta Crucis and abbreviated Beta Cru or β Cru. Mimosa forms part of the prominent asterism called the Southern Cross. It is a binary star or a possible triple star system.

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]
Astrometry
Radial velocity (Rv)+15.6[7] km/s
Proper motion (μ) RA: −42.97[2] mas/yr
Dec.: −16.18[2] mas/yr
Parallax (π)11.71 ± 0.98 mas[2]
Distance280 ± 20 ly
(85 ± 7 pc)
Absolute magnitude (MV)−3.92[8]
Orbit[6]
Primaryβ Crucis A
Companionβ Crucis B
Period (P)1828.0±2.5 days
Semi-major axis (a)8.7 AU
Eccentricity (e)0.38±0.09
Periastron epoch (T)2,449,879±38 HJD
Argument of periastron (ω)
(secondary)		293±9°
Details
A
Mass16[5] M☉
Radius8.4±0.6[5] R☉
Luminosity34,000[5] L☉
Surface gravity (log g)3.6±0.1[5] cgs
Temperature27,000±1,000[5] K
Metallicity [Fe/H]−0.08[9] dex
Rotation3.6 days[5]
Rotational velocity (v sin i)35[5] km/s
Age8 to 11[5] Myr
B
Mass10[6] M☉
Other designations
Mimosa[1] Becrux,[10], β Crucis, CPD−59°4451, FK5 481, HD 111123, HIP 62434, HR 4853, SAO 240259[11]
Database references
SIMBADdata

Nomenclature edit

β Crucis (Latinised to Beta Crucis) is the system's Bayer designation. Although Mimosa is at roughly −60° declination, and therefore not visible north of 30° latitude, in the time of the ancient Greeks and Romans it was visible north of 40° due to the 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 Chinese, 十字架 (Shí Zì Jià), meaning Cross, refers to an asterism consisting of Acrux, Mimosa, 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 edit

 
The constellation Crux

Based on parallax measurements, Mimosa is located at a distance of 280 ly (86 pc) from the Earth. In 1957, German astronomer Wulff-Dieter Heintz discovered that it is a spectroscopic binary with components that are too close together to resolve with a telescope.[19] The pair orbit each other every 5 years with an estimated separation that varies from 5.4 to 12.0 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 β Cephei variable, although with an effective temperature of about 27,000 K it is at the hot edge of the instability strip where such stars are found. It has three different pulsation modes, none of which are radial. The periods of all three modes are in the range of 4.03–4.59 hours. Owing to the first application of polarimetry it is the heaviest star with an age determined by asteroseismology.[21] The star has a stellar classification of B0.5 III, with the 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.[6] In 2007, a third companion was announced, which may be a low mass, pre-main sequence star. The X-ray emission from this star was detected using the Chandra X-ray Observatory. Two other stars, located at angular separations of 44 and 370 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 edit

Mimosa is represented in the flags of Australia, New Zealand, Samoa and Papua New Guinea as one of five stars making up the 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 edit

  1. ^ a b "IAU Catalog of Star Names". Retrieved 28 July 2016.
  2. ^ a b c d e van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600
  3. ^ a b c Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J
  4. ^ Samus, N. N.; Durlevich, O. V.; 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: 02025. Bibcode:2009yCat....102025S.
  5. ^ a b c d e f g h i j k l m n o Cohen, David H.; et al. (June 2008), "Chandra spectroscopy of the hot star βCrucis and the discovery of a pre-main-sequence companion", Monthly Notices of the Royal Astronomical Society, 386 (4): 1855–1871, arXiv:0802.4084, Bibcode:2008MNRAS.386.1855C, doi:10.1111/j.1365-2966.2008.13176.x, S2CID 2924933
  6. ^ a b c d e Aerts, C.; et al. (January 1998), "Evidence for binarity and multiperiodicity in the beta Cephei star beta Crucis", Astronomy and Astrophysics, 329: 137–146, Bibcode:1998A&A...329..137A
  7. ^ Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. Determination of Radial Velocities and Their Applications. Vol. 30. University of Toronto: International Astronomical Union. p. 57. Bibcode:1967IAUS...30...57E.
  8. ^ Kaltcheva, N. T.; Golev, V. K.; Moran, K. (2014), "Massive stellar content of the Galactic supershell GSH 305+01−24", Astronomy & Astrophysics, 562: A69, arXiv:1312.5592, Bibcode:2014A&A...562A..69K, doi:10.1051/0004-6361/201321454, S2CID 54222753
  9. ^ Kilian, J. (February 1994), "Chemical abundances in early B-type stars. 5: Metal abundances and LTE/NLTE comparison", Astronomy and Astrophysics, 282 (3): 867–873, Bibcode:1994A&A...282..867K
  10. ^ a b Hoffleit, Dorrit; Jaschek, Carlos (1991). "The Bright star catalogue". New Haven. Bibcode:1991bsc..book.....H.
  11. ^ "HD 93521", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-05-07.
  12. ^ Wilkinson, Susan (2007), Mimosa: The Life and Times of the Ship That Sailed to Patagonia, Y Lolfa, pp. 56–57, ISBN 978-0-86243-952-1
  13. ^ "Audio Pronunciation Guide". Starry Night Education. Simulation Curriculum Corp. 2009. Retrieved 26 Apr 2019.
  14. ^ , 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. ^ (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.
  18. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 2011-01-30 at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  19. ^ Heintz, W. D. (October 1957), "The radial velocity variation of beta Crucis", The Observatory, 77: 200, Bibcode:1957Obs....77..200H
  20. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  21. ^ Cotton, D. V.; Buzasi, D. B; Aerts, C.; Bailey, J.; et al. (2021), "Polarimetric detection of non-radial oscillation modes in the β Cephei star β Crucis", Nature Astronomy, 6: 154–164, arXiv:2205.11679, doi:10.1038/s41550-021-01531-9, S2CID 244953278
  22. ^ , 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. ^ Rizzuto, Aaron; Ireland, Michael; Robertson, J. G. (October 2011), "Multidimensional Bayesian membership analysis of the Sco OB2 moving group", Monthly Notices of the Royal Astronomical Society, 416 (4): 3108–3117, arXiv:1106.2857, Bibcode:2011MNRAS.416.3108R, doi:10.1111/j.1365-2966.2011.19256.x, S2CID 54510608.
  24. ^ "Astronomy of the Brazilian Flag". FOTW Flags Of The World website.
  25. ^ . 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 edit


April 10, 2024
mimosa, star, mimosa, second, brightest, object, southern, constellation, crux, after, acrux, 20th, brightest, star, night, bayer, designation, crucis, which, latinised, beta, crucis, abbreviated, beta, mimosa, forms, part, prominent, asterism, called, souther. Mimosa is the second brightest object in the southern constellation of Crux after Acrux and the 20th brightest star in the night sky It has the Bayer designation b Crucis which is Latinised to Beta Crucis and abbreviated Beta Cru or b Cru Mimosa forms part of the prominent asterism called the Southern Cross It is a binary star or a possible triple star system MimosaLocation of Mimosa circled Observation dataEpoch J2000 Equinox J2000Constellation CruxPronunciation m ɪ ˈ m oʊ s e 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 CharacteristicsSpectral type B0 5 III 5 B2V 6 U B color index 0 98 3 B V color index 0 23 3 Variable type b Cep 5 AstrometryRadial velocity Rv 15 6 7 km sProper motion m RA 42 97 2 mas yr Dec 16 18 2 mas yrParallax p 11 71 0 98 mas 2 Distance280 20 ly 85 7 pc Absolute magnitude MV 3 92 8 Orbit 6 Primaryb Crucis ACompanionb Crucis BPeriod P 1828 0 2 5 daysSemi major axis a 8 7 AUEccentricity e 0 38 0 09Periastron epoch T 2 449 879 38 HJDArgument of periastron w secondary 293 9 DetailsAMass16 5 M Radius8 4 0 6 5 R Luminosity34 000 5 L Surface gravity log g 3 6 0 1 5 cgsTemperature27 000 1 000 5 KMetallicity Fe H 0 08 9 dexRotation3 6 days 5 Rotational velocity v sin i 35 5 km sAge8 to 11 5 MyrBMass10 6 M Other designationsMimosa 1 Becrux 10 b Crucis CPD 59 4451 FK5 481 HD 111123 HIP 62434 HR 4853 SAO 240259 11 Database referencesSIMBADdata Contents 1 Nomenclature 2 Stellar system 3 In culture 4 References 5 External linksNomenclature editb Crucis Latinised to Beta Crucis is the system s Bayer designation Although Mimosa is at roughly 60 declination and therefore not visible north of 30 latitude in the time of the ancient Greeks and Romans it was visible north of 40 due to the 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 ˈ b eɪ k r ʌ k s 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 Chinese 十字架 Shi Zi Jia meaning Cross refers to an asterism consisting of Acrux Mimosa Gamma Crucis and Delta Crucis 17 Consequently Mimosa itself is known as 十字架三 Shi Zi Jia san English the Third Star of Cross 18 Stellar system edit nbsp The constellation CruxBased on parallax measurements Mimosa is located at a distance of 280 ly 86 pc from the Earth In 1957 German astronomer Wulff Dieter Heintz discovered that it is a spectroscopic binary with components that are too close together to resolve with a telescope 19 The pair orbit each other every 5 years with an estimated separation that varies from 5 4 to 12 0 Astronomical Units 6 The system is only 8 to 11 million years old 5 The primary b 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 nbsp A light curve for Beta Crucis plotted from TESS data 20 b Crucis A is a known b Cephei variable although with an effective temperature of about 27 000 K it is at the hot edge of the instability strip where such stars are found It has three different pulsation modes none of which are radial The periods of all three modes are in the range of 4 03 4 59 hours Owing to the first application of polarimetry it is the heaviest star with an age determined by asteroseismology 21 The star has a stellar classification of B0 5 III with the 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 b Crucis B may be a main sequence star with a stellar class of B2 6 In 2007 a third companion was announced which may be a low mass pre main sequence star The X ray emission from this star was detected using the Chandra X ray Observatory Two other stars located at angular separations of 44 and 370 arcseconds are likely optical companions that are not physically associated with the system The b 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 editMimosa is represented in the flags of Australia New Zealand Samoa and Papua New Guinea as one of five stars making up the 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 edit a b IAU Catalog of Star Names Retrieved 28 July 2016 a b c d e van Leeuwen F November 2007 Validation of the new Hipparcos reduction Astronomy and Astrophysics 474 2 653 664 arXiv 0708 1752 Bibcode 2007A amp A 474 653V doi 10 1051 0004 6361 20078357 S2CID 18759600 a b c Johnson H L et al 1966 UBVRIJKL photometry of the bright stars Communications of the Lunar and Planetary Laboratory 4 99 99 Bibcode 1966CoLPL 4 99J Samus N N Durlevich O V 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 02025 Bibcode 2009yCat 102025S a b c d e f g h i j k l m n o Cohen David H et al June 2008 Chandra spectroscopy of the hot star bCrucis and the discovery of a pre main sequence companion Monthly Notices of the Royal Astronomical Society 386 4 1855 1871 arXiv 0802 4084 Bibcode 2008MNRAS 386 1855C doi 10 1111 j 1365 2966 2008 13176 x S2CID 2924933 a b c d e Aerts C et al January 1998 Evidence for binarity and multiperiodicity in the beta Cephei star beta Crucis Astronomy and Astrophysics 329 137 146 Bibcode 1998A amp A 329 137A Evans D S June 20 24 1966 The Revision of the General Catalogue of Radial Velocities In Batten Alan Henry Heard John Frederick eds Determination of Radial Velocities and their Applications Proceedings from IAU Symposium no 30 Determination of Radial Velocities and Their Applications Vol 30 University of Toronto International Astronomical Union p 57 Bibcode 1967IAUS 30 57E Kaltcheva N T Golev V K Moran K 2014 Massive stellar content of the Galactic supershell GSH 305 01 24 Astronomy amp Astrophysics 562 A69 arXiv 1312 5592 Bibcode 2014A amp A 562A 69K doi 10 1051 0004 6361 201321454 S2CID 54222753 Kilian J February 1994 Chemical abundances in early B type stars 5 Metal abundances and LTE NLTE comparison Astronomy and Astrophysics 282 3 867 873 Bibcode 1994A amp A 282 867K a b Hoffleit Dorrit Jaschek Carlos 1991 The Bright star catalogue New Haven Bibcode 1991bsc book H HD 93521 SIMBAD Centre de donnees astronomiques de Strasbourg retrieved 2022 05 07 Wilkinson Susan 2007 Mimosa The Life and Times of the Ship That Sailed to Patagonia Y Lolfa pp 56 57 ISBN 978 0 86243 952 1 Audio Pronunciation Guide Starry Night Education Simulation Curriculum Corp 2009 Retrieved 26 Apr 2019 MIMOSA Beta Crucis Stars university of Illinois archived from the original on 2005 12 22 retrieved 2011 12 30 IAU Working Group on Star Names WGSN Retrieved 22 May 2016 Bulletin of the IAU Working Group on Star Names No 1 PDF Retrieved 28 July 2016 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 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 Heintz W D October 1957 The radial velocity variation of beta Crucis The Observatory 77 200 Bibcode 1957Obs 77 200H MAST Barbara A Mikulski Archive for Space Telescopes Space Telescope Science Institute Retrieved 8 December 2021 Cotton D V Buzasi D B Aerts C Bailey J et al 2021 Polarimetric detection of non radial oscillation modes in the b Cephei star b Crucis Nature Astronomy 6 154 164 arXiv 2205 11679 doi 10 1038 s41550 021 01531 9 S2CID 244953278 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 Rizzuto Aaron Ireland Michael Robertson J G October 2011 Multidimensional Bayesian membership analysis of the Sco OB2 moving group Monthly Notices of the Royal Astronomical Society 416 4 3108 3117 arXiv 1106 2857 Bibcode 2011MNRAS 416 3108R doi 10 1111 j 1365 2966 2011 19256 x S2CID 54510608 Astronomy of the Brazilian Flag FOTW Flags Of The World website Mighty Ships DiscoveryHD ca CTV Global Media Archived from the original on 15 September 2008 Retrieved 25 November 2013 a href Template Cite web html title Template Cite web cite web a CS1 maint unfit URL link External links edithttp jumk de astronomie big stars becrux shtml Retrieved from https en wikipedia org w index php title Mimosa star amp oldid 1197475878, wikipedia, wiki, book, books, library,

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