Astronomy:Mu Librae

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Short description: Star in the constellation Libra
Mu Librae
Observation data
Equinox J2000.0]] (ICRS)
Constellation Libra
Right ascension  14h 49m 19.05130s[1]
Declination −14° 08′ 56.4766″[1]
Apparent magnitude (V) 5.32[2] (5.69 + 6.72[3] + 14.70[4])
Characteristics
Spectral type A1pSrCrEu + A6m[3]
B−V color index +0.07[2]
Astrometry
Radial velocity (Rv)−3.2±1.4[5] km/s
Proper motion (μ) RA: −65.95[1] mas/yr
Dec.: −14.54[1] mas/yr
Parallax (π)13.71 ± 0.69[1] mas
Distance240 ± 10 ly
(73 ± 4 pc)
Absolute magnitude (MV)1.32±0.20[6]
Details
μ Lib A
Mass2.31±0.12[7] M
Radius2.59[8] R
Luminosity41.7[7] L
Temperature9,592±260[7] K
Rotational velocity (v sin i)29.0±1.7[7] km/s
Age417[6] Myr
μ Lib B
Radius2.59[8] R
Rotational velocity (v sin i)32.0±6[8] km/s
Other designations
μ Lib, BD−13° 3986, HD 130559, HIP 72489, HR 5523, SAO 158821.[9]
Database references
SIMBADdata

μ Librae (Latinised as Mu Librae) is the Bayer designation for a probable triple star[3] system in the zodiac constellation of Libra. They have a combined apparent visual magnitude of 5.32,[2] which is bright enough to be faintly visible to the naked eye. With an annual parallax shift of 13.71 mas,[1] the system is located at an estimated distance of around 240 light years.

The inner pair consists of two A-type stars that, as of 2006, had an angular separation of 1.79 arc seconds along a position angle of 5.5°.[10] They have an estimated physical separation of 139 AU.[8] The primary, component A, is a visual magnitude 5.69[3] magnetic Ap star showing overabundances of the elements aluminum, strontium, chromium, and europium.[7] Hence, it has a stellar classification of A1pSrEuCr.[3] It is a photometric variable with periods of 25.3992±0.1970 d and 1.8871±0.0008 d. The surface magnetic field strength is 1,375 Gauss.[7]

The secondary, component B, is an Am star with a stellar classification of A6m.[3] It has a visual magnitude of 6.72.[3] The tertiary member, component C, is a magnitude 14.70 star at an angular separation of 12.90 arc seconds along a position angle of 294°, as of 2000.[4]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 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, Bibcode1968MNSSA..27...11C. 
  3. 3.0 3.1 3.2 3.3 3.4 3.5 3.6 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode2008MNRAS.389..869E. 
  4. 4.0 4.1 Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466, doi:10.1086/323920, Bibcode2001AJ....122.3466M, http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/wds, retrieved 2015-07-22. 
  5. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics 546: 14, doi:10.1051/0004-6361/201219219, A61, Bibcode2012A&A...546A..61D. 
  6. 6.0 6.1 Kochukhov, O.; Bagnulo, S. (2006), "Evolutionary state of magnetic chemically peculiar stars", Astronomy and Astrophysics 450 (2): 763, doi:10.1051/0004-6361:20054596, Bibcode2006A&A...450..763K. 
  7. 7.0 7.1 7.2 7.3 7.4 7.5 Wraight, K. T. et al. (February 2012), "A photometric study of chemically peculiar stars with the STEREO satellites - I. Magnetic chemically peculiar stars", Monthly Notices of the Royal Astronomical Society 420 (1): 757–772, doi:10.1111/j.1365-2966.2011.20090.x, Bibcode2012MNRAS.420..757W. 
  8. 8.0 8.1 8.2 8.3 Howe, K. S.; Clarke, C. J. (January 2009), "An analysis of v sin (i) correlations in early-type binaries", Monthly Notices of the Royal Astronomical Society 392 (1): 448–454, doi:10.1111/j.1365-2966.2008.14073.x, Bibcode2009MNRAS.392..448H. 
  9. "mu. Lib". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=mu.+Lib. 
  10. Mason, Brian D. et al. (October 2007), "Speckle Interferometry at the US Naval Observatory. XIII.", The Astronomical Journal 134 (4): 1671–1678, doi:10.1086/521555, Bibcode2007AJ....134.1671M, http://www.dtic.mil/get-tr-doc/pdf?AD=ADA473702.