Beta Andromedae

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This article is about the star. For the target drones, see Galileo Mirach 150 and Galileo Mirach 26.
Beta Andromedae
Diagram showing star positions and boundaries of the Andromeda constellation and its surroundings
Cercle rouge 100%.svg

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 type M0 III[4]
U−B color index +1.96[2]
B−V color index +1.57[2]
V−R color index 0.9[5]
R−I color index +1.00[6]
Variable type Semiregular[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
Distance 197 ± 7 ly
(61 ± 2 pc)
Absolute magnitude (MV) –1.76[8]
Details
Mass 3–4[9] M
Radius 100[10] R
Luminosity 1,995[10] L
Surface gravity (log g) 1.52[11] cgs
Temperature 3,842[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
SIMBAD data

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[edit]

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[edit]

References[edit]

  1. ^ a b c d e f 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. ^ a b c d 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. ^ a b c d 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. ^ a b 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. ^ a b 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. ^ a b 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. ^ a b c d e 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. ^ a b c d 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. ^ a b c d e f g 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. ^ a b c 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[edit]

  • 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[edit]

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