Beta Andromedae

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Beta Andromedae
Diagram showing star positions and boundaries of the Andromeda constellation and its surroundings

Location of β Andromedae (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Andromeda
Right ascension 01h 09m 43.92388s[1]
Declination +35° 37′ 14.0075″[1]
Apparent magnitude (V)2.05[2] (2.01 to 2.10)[3]
Characteristics
Spectral typeM0 III[4]
U−B color index+1.96[2]
B−V color index+1.57[2]
V−R color index0.9[5]
R−I color index+1.00[6]
Variable typeSemiregular[3]
Astrometry
Radial velocity (Rv)0.06 ± 0.13[7] km/s
Proper motion (μ) RA: 175.90[1] mas/yr
Dec.: −112.20[1] mas/yr
Parallax (π)16.52 ± 0.56[1] mas
Distance197 ± 7 ly
(61 ± 2 pc)
Absolute magnitude (MV)–1.76[8]
Details
Mass3–4[9] M☉
Radius100[10] R☉
Luminosity1,995[10] L☉
Surface gravity (log g)1.52[11] cgs
Temperature3,842[11] K
Metallicity [Fe/H]–0.05[11] dex
Rotational velocity (v sin i)7.2[10] km/s
Other designations
Mirach, Merach, Mirac, Mizar, β And, Beta Andromedae, Beta And, 43 Andromedae, 43 And, BD+34°198, FK5 42, GJ 53.3, GJ 9044, HD 6860, HIP 5447, HR 337, LTT 10420, NLTT 3848, SAO 54471, WDS 01097+3537A.[5][12]
Database references
SIMBADdata

Beta Andromedae (Beta And, β And, β Andromedae) is the Bayer designation for a prominent star in the northern constellation of Andromeda. It has the traditional name Mirach, which is also spelled Merach, Mirac, Mirak.[12] β Andromedae is located northeast of the Great Square of Pegasus and is theoretically visible to all observers north of 54° S. The galaxy NGC 404, also known as Mirach's Ghost, is visible seven arc-minutes away.[13]

This star has an average apparent visual magnitude of 2.05,[2] which makes it the brightest star in the constellation. However, the luminosity varies slightly from magnitude +2.01 to +2.10.[3] Based upon parallax measurements, it is located at a distance of roughly 197 light-years (60 parsecs) from Earth.[1] The apparent magnitude of this star is reduced by 0.06 from extinction caused by the gas and dust along the line of sight.[7]

Properties

Beta Andromedae is a red giant with a stellar classification of M0 III.[4] Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[14] It is suspected of being a semiregular variable star whose apparent visual magnitude varies from +2.01 to +2.10.[3] At this stage of the star's evolution, the outer envelope has expanded to around 100 times the size of the Sun.[10] It is radiating 1,995[10] times the luminosity of the Sun at an effective temperature of 3,842 K.[11]

Naming and etymology

  • The name Mirach, and its variations, such as Mirac, Mirar, Mirath, Mirax, etc. (the name is spelled Merach in Burritt's The Geography of the Heavens)[15] come from the star's description in the Alfonsine Tables of 1521 as super mizar.[12] Here, mirat is a corruption of the Arabic ميزر mīzar "girdle", which appeared in a Latin translation of the Almagest.[12] This word refers to Mirach's position at the left hip of the princess Andromeda.[16]
  • Medieval astronomers writing in Arabic called β Andromedae Janb al-Musalsalah (English: The Side of the Chained (Lady)); it was part of the 26th manzil (Arabian lunar mansion) Batn al-Hũt, the Belly of the Fish, or Qalb al-Hũt, the Heart of the Fish.[12][17] The star has also been called Cingulum and Ventrale.[12] This al-Hũt was an indigenous Arabic constellation, not the Western "Northern Fish" part of the constellation Pisces.[17] These names are not from the Arabic marãqq, loins, because it was never called al-Marãqq in Arabian astronomy.[17] Al Rishã', the Cord (of the well-bucket), on al-Sũfĩ's star map. It is origin of the proper name Alrescha for Alpha Piscium.[12][18][19]
  • In Chinese, 奎宿 (Kuí Sù), meaning Legs (asterism), refers to an asterism consisting of β Andromedae, η Andromedae, 65 Piscium, ζ Andromedae, ε Andromedae, δ Andromedae, π Andromedae, ν Andromedae, μ Andromedae, σ Piscium, τ Piscium, 91 Piscium, υ Piscium, φ Piscium, χ Piscium and ψ¹ Piscium. Consequently, β Andromedae itself is known as 奎宿九 (Kuí Sù jiǔ, English: the Ninth Star of Legs.)[20]
  • The people of Micronesia named this star as Kyyw "The Porpoise", and become once of Micronesian month name.[21]
  • Mirach is listed in MUL.APIN as KA.MUSH.I.KU.E, meaning "the Deleter" (the alternative star is α Cas).[22]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 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 
  2. ↑ 2.0 2.1 2.2 2.3 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99), Bibcode:1966CoLPL...4...99J 
  3. ↑ 3.0 3.1 3.2 3.3 NSV 414, database entry, table of suspected variable stars, Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.), N. N. Samus, O. V. Durlevich, et al., CDS ID II/250.
  4. ↑ 4.0 4.1 Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics 11 (1): 29, Bibcode:1973ARA&A..11...29M, doi:10.1146/annurev.aa.11.090173.000333 
  5. ↑ 5.0 5.1 NAME MIRACH -- Variable Star, database entry, SIMBAD. Accessed on line August 12, 2008.
  6. ↑ HR 337, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line August 12, 2008.
  7. ↑ 7.0 7.1 Famaey, B. et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272 
  8. ↑ Elgarøy, Øystein; Engvold, Oddbjørn; Lund, Niels (March 1999), "The Wilson-Bappu effect of the MgII K line - dependence on stellar temperature, activity and metallicity", Astronomy and Astrophysics 343: 222–228, Bibcode:1999A&A...343..222E 
  9. ↑ Mirach, Stars, Jim Kaler. Accessed on line August 13, 2008.
  10. ↑ 10.0 10.1 10.2 10.3 10.4 Massarotti, Alessandro et al. (January 2008), "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity", The Astronomical Journal 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209 
  11. ↑ 11.0 11.1 11.2 11.3 Soubiran, C. et al. (2008), "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants", Astronomy and Astrophysics 480 (1): 91–101, arXiv:0712.1370, Bibcode:2008A&A...480...91S, doi:10.1051/0004-6361:20078788 
  12. ↑ 12.0 12.1 12.2 12.3 12.4 12.5 12.6 Allen, R. A. (1899), Star-names and Their Meanings, p. 36 
  13. ↑ Darling, David, "Mirach's Ghost (NGC 404)", The Internet Encyclopedia of Science, retrieved 2008-08-15 
  14. ↑ Garrison, R. F. (December 1993), "Anchor Points for the MK System of Spectral Classification", Bulletin of the American Astronomical Society 25: 1319, Bibcode:1993AAS...183.1710G, retrieved 2012-02-04 
  15. ↑ p. 18, The Geography of the Heavens, Elijah Hinsdale Burritt, Hiram Mattison, and Henry Whitall, New York: Sheldon & Company, 1856.
  16. ↑ Mirach, MSN Encarta. Accessed on line August 19, 2008. Archived 2009-10-31.
  17. ↑ 17.0 17.1 17.2 George A.Davis Jr. (1971) Selected List of Star Names, p. 5.
  18. ↑ ibid. p. 19.
  19. ↑ Kunitsch, Paul; Smart, Tim (2006). A Dictionary of Modern Star names: A Short Guide to 254 Star Names and Their Derivations. Cambridge, Massachusetts: Sky Publishing Corp. p. 50. ISBN 978-1-931559-44-7. 
  20. ↑ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日
  21. ↑ p. 345, Exploring Ancient Skies: A Survey of Ancient and Cultural Astronomy, David H. Kelley, Eugene F. Milone, Anthony F. (FRW) Aveni, Berlin, Springer, 2011.
  22. ↑ Rogers, J. H. (February 1998). "Origins of the ancient constellations: I. The Mesopotamian traditions". Journal of the British Astronomical Association, no.1 108: 9–28. Bibcode:1998JBAA..108....9R. 

Further reading

  • Davis Jr., G. A., (1971) Pronunciations, Derivations, and Meanings of a Selected List of Star Names, (rep.) Cambridge, Sky Publishing Corp.
  • Kunitzsch, P., (1959) Arabische Sternnamen in Europa
  • Kunitzsch. P., (ed.) (1990) Der Sternkatalog des Almagest, Band II

External links

Coordinates: 01h 09m 43.9236s, +35° 37′ 14.008″

Stars of Andromeda
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