Beta Andromedae

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This article is about the star. For the target drones, see Galileo Mirach 150 and Galileo Mirach 26.
β Andromedae
Andromeda constellation map (1).png
β Andromedae is left of center
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Andromeda
Right ascension 01h 09m 43.9236s[1]
Declination +35° 37′ 14.008″[1]
Apparent magnitude (V) 2.01 to 2.10[2]
Characteristics
Spectral type M0III[1]
U−B color index +1.96[3]
B−V color index +1.58[3]
V−R color index 0.9[1]
R−I color index +1.00[3]
Variable type Semiregular[2]
Astrometry
Radial velocity (Rv) 0.3 ± 0.9[1] km/s
Proper motion (μ) RA: 175.59[1] mas/yr
Dec.: −112.23[1] mas/yr
Parallax (π) 16.36 ± 0.76[1] mas
Distance 199 ± 9 ly
(61 ± 3 pc)
Absolute magnitude (MV) −1.9[4]
Details
Mass 3–4[5] M☉
Radius 90[5] R☉
Luminosity 1,900[5] L☉
Temperature 3,800[5] K
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.[1][6]
Database references
SIMBAD data

Beta Andromedae (Beta And, β And, β Andromedae) is a red giant star in the constellation of Andromeda. It has the traditional name Mirach (also spelled Merach, Mirac, Mirak).[6] It has spectral class M0, and is approximately 200 light years away.[1] Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[7] It is classified as a suspected semiregular variable star whose apparent visual magnitude varies from +2.01 to +2.10.[2]

Contents

[edit] Observation

β Andromedae is located northeast of the Great Square of Pegasus and is theoretically visible to all observers north of 54° S. Its location in the sky is shown on the left. The galaxy NGC 404, also known as Mirach's Ghost, is visible seven arc-minutes away.[8]

[edit] 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)[9] come from the star's description in the Alfonsine Tables of 1521 as super mizar.[6] Here, mirat is a corruption of the Arabic ميزر mīzar "girdle", which appeared in a Latin translation of the Almagest.[6] This word refers to Mirach's position at the left hip of the princess Andromeda.[10]

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.[6][11] The star has also been called Cingulum and Ventrale.[6] This al-Hũt was an indigenous Arabic constellation, not the Western "Northern Fish" part of the constellation Pisces.[11] These names are not from the Arabic marãqq, loins, because it was never called al-Marãqq in Arabian astronomy.[11] 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.[6][12][13]

In Chinese, 奎宿 (Kuí Sù), meaning Legs (asterism), refers to an asterism consisting of β Andromedae, η Andromedae, 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.[14] Consequently, β Andromedae itself is known as 奎宿九 (Kuí Sù jiǔ, English: the Ninth Star of Legs.)[15]

The people of Micronesia named this star as Kyyw "The Porpoise", and become once of Micronesian month name.[16]

Mirach is listed in MUL.APIN as KA.MUSH.I.KU.E, meaning "the Deleter" (the alternative star is α Cas).[17].

[edit] Notes and references

  1. ^ a b c d e f g h i j NAME MIRACH -- Variable Star, database entry, SIMBAD. Accessed on line August 12, 2008.
  2. ^ a b c 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.
  3. ^ a b c 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.
  4. ^ From apparent magnitude and parallax.
  5. ^ a b c d Mirach, Stars, Jim Kaler. Accessed on line August 13, 2008.
  6. ^ a b c d e f g Richard Hinckley Allen (1899) Star-names and Their Meanings, p. 36.
  7. ^ 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, http://www.astro.utoronto.ca/~garrison/mkstds.html, retrieved 2012-02-04 
  8. ^ Mirach's Ghost (NGC 404), The Internet Encyclopedia of Science, David Darling. Accessed on line August 15, 2008.
  9. ^ p. 18, The Geography of the Heavens, Elijah Hinsdale Burritt, Hiram Mattison, and Henry Whitall, New York: Sheldon & Company, 1856.
  10. ^ Mirach, MSN Encarta. Accessed on line August 19, 2008. Archived 2009-10-31.
  11. ^ a b c George A.Davis Jr. (1971) Selected List of Star Names, p. 5.
  12. ^ ibid. p. 19.
  13. ^ Kunitsch, P., Smart, T., (2006) A Dictionary of Modern Star names: A Shoert Guide to 254 Star Names and Their Derivations, Cambridge, Sky Publishing Corp., p. 50.
  14. ^ (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.
  15. ^ (Chinese) 香港太空館 - 研究資源 - 亮星中英對照表, Hong Kong Space Museum. Accessed on line November 23, 2010.
  16. ^ 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.
  17. ^ 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. 

[edit] Further reading and external links

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

Stars of Andromeda
Bayer
Flamsteed
Nearby
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