Astronomy:Beta Microscopii

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Short description: Constellation Microscopium star
β Microscopii
Microscopium constellation map.svg
Red circle.svg
Location of β Microscopii (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Microscopium
Right ascension  20h 51m 58.7618s[1]
Declination −33° 10′ 40.7051″[1]
Apparent magnitude (V) 6.05±0.01[2]
Characteristics
Spectral type A1 IV[3]
B−V color index +0.03[4]
Astrometry
Radial velocity (Rv)−12±4.3[5] km/s
Proper motion (μ) RA: +7.712[1] mas/yr
Dec.: −5.568[1] mas/yr
Parallax (π)6.5022 ± 0.0451[1] mas
Distance502 ± 3 ly
(154 ± 1 pc)
Absolute magnitude (MV)+0.22[6]
Details
Mass2.96[7] M☉
Radius3.5±0.1[8] R☉
Luminosity77.25[6] L☉
Surface gravity (log g)3.58[9] cgs
Temperature8,942[10] K
Metallicity [Fe/H]0.00[11] dex
Rotational velocity (v sin i)275±3[12] km/s
Age337[11] Myr
Other designations
β Mic, CD−33° 15245, HD 198529, HIP 102989, HR 7979, SAO 212499[13]
Database references
SIMBADdata

Beta Microscopii (Beta Mic), Latinized from β Microscopii, is a solitary star in the constellation Microscopium. It is close to the lower limit of stars that are visible to the naked eye having an apparent visual magnitude of 6.05[2] Based upon an annual parallax shift of 6.5022 mas as seen from Earth,[1] this star is located 502 light years away[1] from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.19 due to interstellar dust.[11]

Beta Mic has a stellar classification of A1 IV,[3] indicating that it is an evolved A-type subgiant. Older sources give it a class of A2 Vn,[14] suggesting that it is an A-type main-sequence star with nebulous absorption lines due to rapid rotation. Consistent with the older classification, the star is spinning rapidly with a projected rotational velocity of 275 km/s.[12] The star has 2.96 times the mass of the Sun[7] and due to its evolved status, has a radius of 3.5 R☉.[8] It radiates at 77.2 times the luminosity of the Sun[6] from its photosphere at an effective temperature of 8,942 K,[10] giving a white hue. Beta Mic has a solar metallicity and is estimated to be around 340 million years old.[11]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  2. ↑ 2.0 2.1 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27–L30. ISSN 0004-6361. Bibcode: 2000A&A...355L..27H. 
  3. ↑ 3.0 3.1 Houk, N. (1982). Michigan Catalogue of Two-dimensional Spectral Types for the HD stars. Volume_3. Declinations -40_ƒ0 to -26_ƒ0.. Bibcode: 1982mcts.book.....H. 
  4. ↑ Corben, P. M.; Stoy, R. H. (1968), "Photoelectric Magnitudes and Colours for Bright Southern Stars", Monthly Notes of the Astronomical Society of Southern Africa 27: 11, Bibcode: 1968MNSSA..27...11C. 
  5. ↑ Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system", Astronomy Letters 32 (11): 759–771, doi:10.1134/S1063773706110065, Bibcode: 2006AstL...32..759G. 
  6. ↑ 6.0 6.1 6.2 Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation" (in en). Astronomy Letters 38 (5): 331–346. doi:10.1134/S1063773712050015. ISSN 1063-7737. Bibcode: 2012AstL...38..331A. 
  7. ↑ 7.0 7.1 Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics 657: A7. doi:10.1051/0004-6361/202142146. ISSN 0004-6361. Bibcode: 2022A&A...657A...7K. 
  8. ↑ 8.0 8.1 Stassun, Keivan G. et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. ISSN 0004-6256. Bibcode: 2019AJ....158..138S. 
  9. ↑ Steinmetz, Matthias et al. (27 July 2020). "The Sixth Data Release of the Radial Velocity Experiment (Rave). II. Stellar Atmospheric Parameters, Chemical Abundances, and Distances". The Astronomical Journal 160 (2): 83. doi:10.3847/1538-3881/ab9ab8. Bibcode: 2020AJ....160...83S. 
  10. ↑ 10.0 10.1 Anders, F. et al. (February 2022). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G = 18.5". Astronomy & Astrophysics 658: A91. doi:10.1051/0004-6361/202142369. ISSN 0004-6361. Bibcode: 2022A&A...658A..91A. 
  11. ↑ 11.0 11.1 11.2 11.3 Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters 38 (12): 771–782. doi:10.1134/S1063773712120031. ISSN 0320-0108. Bibcode: 2012AstL...38..771G. 
  12. ↑ 12.0 12.1 Díaz, C. G.; González, J. F.; Levato, H.; Grosso, M. (July 2011). "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum". Astronomy & Astrophysics 531: A143. doi:10.1051/0004-6361/201016386. ISSN 0004-6361. Bibcode: 2011A&A...531A.143D. 
  13. ↑ "bet Mic". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=bet+Mic. 
  14. ↑ Evans, D. S. (1966). "Fundamental data for Southern stars (6th list).". Royal Greenwich Observatory Bulletins 110: 185. Bibcode: 1966RGOB..110..185E. 
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