Mu Lyrae

In this article, we will delve into the fascinating world of Mu Lyrae. This topic is of great interest to a wide spectrum of people, since its impact is felt in different areas of daily life. From historical aspects to its relevance today, Mu Lyrae has been the subject of studies, debates and reflections by experts and enthusiasts alike. In the next lines, we will explore the various facets of Mu Lyrae, analyzing its importance, its implications and its possible future developments. Join us on this tour of Mu Lyrae and discover everything this exciting topic has to offer!

Mu Lyrae
Observation data
Epoch J2000      Equinox J2000
Constellation Lyra
Right ascension 18h 24m 13.78599s[1]
Declination +39° 30′ 26.0473″[1]
Apparent magnitude (V) 5.11[2]
Characteristics
Evolutionary stage subgiant[3]
Spectral type A3IVn[4]
U−B color index +0.07[5]
B−V color index +0.047±0.004[2]
Astrometry
Radial velocity (Rv)−24.0±4.2[2] km/s
Proper motion (μ) RA: −21.825±0.260[1] mas/yr
Dec.: −4.460±0.288[1] mas/yr
Parallax (π)7.9161±0.1438 mas[1]
Distance412 ± 7 ly
(126 ± 2 pc)
Absolute magnitude (MV)–0.53[2]
Details[3]
Mass3.04±0.04 M☉
Radius5.80[a] (oblate[6]) R☉
Luminosity200+23
−10 L☉
Temperature9,016+167
−165 K
Rotational velocity (v sin i)165 km/s
Other designations
μ Lyr, 2 Lyrae, BD+39°3410, HD 169702, HIP 90191, HR 6903, SAO 66943[7]
Database references
SIMBADdata

μ Lyrae, Latinized as Mu Lyrae, is a solitary[8] star in the northern constellation Lyra. It has the traditional name Alathfar /əˈlæθfɑːr/, from the Arabic الأظفار al-ʼaẓfār "the talons (of the swooping eagle)", a name it shares with Eta Lyrae[9] (though the latter is spelled "Aladfar" by the IAU).[10] This white-hued object is visible to the naked eye as faint point of light with an apparent visual magnitude of 5.11.[2] It is located approximately 412 light years distant from the Sun based on parallax,[1] but is drifting closer with a radial velocity of −24 km/s.[2]

This object has evolved off the main sequence,[3] becoming a subgiant with a stellar classification of A0 IV.[4] It has a fairly high rate of spin, showing a projected rotational velocity of 165 km/s.[3] This is giving the star an equatorial bulge that is an estimated 17% larger than the polar radius.[6] The star has three times the mass of the Sun and about 5.8 times the Sun's radius. It is radiating 200 times the Sun's luminosity from its photosphere at an effective temperature of 9,016 K.[3]

Notes

  1. ^ Calculated, using the Stefan-Boltzmann law and the star's effective temperature and luminosity, with respect to the solar nominal effective temperature of 5,772 K:

References

  1. ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c d e f Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  3. ^ a b c d e Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
  4. ^ a b Van Belle, Gerard T.; von Braun, Kaspar (2009). "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars". The Astrophysical Journal. 694 (2): 1085–1098. arXiv:0901.1206. Bibcode:2009ApJ...694.1085V. doi:10.1088/0004-637X/694/2/1085. S2CID 18370219.
  5. ^ Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
  6. ^ a b van Belle, Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20 (1): 51, arXiv:1204.2572, Bibcode:2012A&ARv..20...51V, doi:10.1007/s00159-012-0051-2, S2CID 119273474
  7. ^ "mu Lyr". SIMBAD. Centre de données astronomiques de Strasbourg.
  8. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
  9. ^ Allen, Richard Hinckley (2018). Star-Names and Their Meanings. Creative Media Partners, LLC. ISBN 978-0-344-21405-9.
  10. ^ "Naming Stars". IAU.org. Retrieved 16 December 2017.
  • Kaler, James B. (October 7, 2011). "Al Athfar". STARS. Retrieved 2019-09-25.