{{short description|Star in the constellation Libra}} {{Starbox begin}} {{Starbox image | image = {{Location mark |image=Libra constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=μ Librae |x=670|y=350 }} | caption = Location of μ Librae (circled in red) }} {{Starbox observe | epoch = [[J2000.0]] | equinox = [[J2000.0]] ([[International Celestial Reference System|ICRS]]) | constell = [[Libra (constellation)|Libra]] | ra = {{RA|14|49|19.05130}}<ref name=vanLeeuwen2007/> | dec = {{DEC|−14|08|56.4766}}<ref name=vanLeeuwen2007/> | appmag_v = 5.32<ref name=Corben1968/> {{nowrap|(5.69 + 6.72<ref name=Eggleton2008/> + 14.70<ref name=Mason2014/>)}} }} {{Starbox character | class = {{nowrap|A1pSrCrEu + A6m}}<ref name=Eggleton2008/> | b-v = +0.07<ref name=Corben1968/> | u-b = | r-i = | variable = }} {{Starbox astrometry | radial_v = {{Val|−3.2|1.4}}<ref name=deBruijne2012/> | prop_mo_ra = −65.95<ref name=vanLeeuwen2007/> | prop_mo_dec = −14.54<ref name=vanLeeuwen2007/> | parallax = 13.71 | p_error = 0.69 | parallax_footnote = <ref name=vanLeeuwen2007/> | absmag_v = {{Val|1.32|0.20}}<ref name=Kochukhov2006/> }} {{Starbox detail | source = | component1 = μ Lib A | mass = {{Val|2.31|0.12}}<ref name=Wraight2012/> | radius = 2.59<ref name=Howe2009/> | luminosity = 41.7<ref name=Wraight2012/> | temperature = {{Val|9592|260|fmt=commas}}<ref name=Wraight2012/> | gravity = | metal_fe = | rotational_velocity = {{Val|29.0|1.7}}<ref name=Wraight2012/> | age_myr = 417<ref name=Kochukhov2006/> | component2 = μ Lib B | radius2 = 2.59<ref name=Howe2009/> | rotational_velocity2 = {{Val|32.0|6}}<ref name=Howe2009/> }} {{Starbox catalog | names = [[Bayer designation|μ Lib]], [[Durchmusterung|BD]]−13°3986, [[Henry Draper Catalogue|HD]] 130559, [[Hipparcos Catalogue|HIP]] 72489, [[Harvard Revised catalogue|HR]] 5523, [[Smithsonian Astrophysical Observatory Star Catalog|SAO]] 158821<ref name=SIMBAD/> }} {{Starbox reference | Simbad = mu+Lib }} {{Starbox end}} '''μ Librae''' (Latinised as '''Mu Librae''') is a probable [[triple star]]<ref name=Eggleton2008/> system in the [[zodiac]] [[constellation]] of [[Libra (constellation)|Libra]]. They have a combined [[apparent visual magnitude]] of 5.32,<ref name=Corben1968/> which is bright enough to be faintly visible to the naked eye. With an annual [[stellar parallax|parallax shift]] of 13.71 [[milliarcsecond|mas]],<ref name=vanLeeuwen2007/> the system is located at an estimated distance of around 240 [[light year]]s.
The inner pair consists of two [[A-type star]]s that, as of 2006, had an [[angular separation]] of 1.79 [[arc second]]s along a [[position angle]] of 5.5°.<ref name=Mason2007/> They have an estimated physical separation of 139 [[astronomical unit|AU]].<ref name=Howe2009/> The primary, component A, is a visual magnitude 5.69<ref name=Eggleton2008/> magnetic [[Ap star]] showing overabundances of the elements aluminum, strontium, chromium, and europium.<ref name=Wraight2012/> Hence, it has a [[stellar classification]] of A1pSrEuCr.<ref name=Eggleton2008/> It is a photometric variable with periods of {{Val|25.3992|0.1970|u=d}} and {{Val|1.8871|0.0008|u=d}}. The surface magnetic field strength is 1,375 Gauss.<ref name=Wraight2012/>
The secondary, component B, is an [[Am star]] with a [[stellar classification]] of A6m.<ref name=Eggleton2008/> It has a visual magnitude of 6.72.<ref name=Eggleton2008/> 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.<ref name=Mason2014/>
==References== <references>
<ref name=vanLeeuwen2007>{{citation | title=Validation of the new Hipparcos reduction | last1=van Leeuwen | first1=F. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | date=2007 | arxiv=0708.1752 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 | s2cid=18759600 | postscript=. }}</ref>
<ref name=Mason2014>{{citation | display-authors=1 | last1=Mason | first1=B. D. | last2=Wycoff | first2=G. L. | last3=Hartkopf | first3=W. I. | last4=Douglass | first4=G. G. | last5=Worley | first5=C. E. | title=The Washington Visual Double Star Catalog | journal=The Astronomical Journal | year=2014 | volume=122 | issue=6 | page=3466 | bibcode=2001AJ....122.3466M | postscript=. | url=http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/wds | accessdate=2015-07-22 | doi = 10.1086/323920 | doi-access=free }}</ref>
<ref name=Kochukhov2006>{{citation | title=Evolutionary state of magnetic chemically peculiar stars | last1=Kochukhov | first1=O. | last2=Bagnulo | first2=S. | journal=Astronomy and Astrophysics | postscript=. | volume=450 | issue=2 | pages=763 | year=2006 | doi=10.1051/0004-6361:20054596 | bibcode=2006A&A...450..763K |arxiv = astro-ph/0601461 | s2cid=18596834 }}</ref>
<ref name=Corben1968>{{citation | last1=Corben | first1=P. M. | last2=Stoy | first2=R. H. | title=Photoelectric Magnitudes and Colours for Bright Southern Stars | journal=Monthly Notes of the Astronomical Society of Southern Africa | volume=27 | page=11 | year=1968 | bibcode=1968MNSSA..27...11C | postscript=. }}</ref>
<ref name=Mason2007>{{citation | title=Speckle Interferometry at the US Naval Observatory. XIII. | last1=Mason | first1=Brian D. | last2=Hartkopf | first2=William I. | last3=Wycoff | first3=Gary L. | last4=Wieder | first4=Gary | display-authors=1 | postscript=. | journal=The Astronomical Journal | volume=134 | issue=4 | pages=1671–1678 | date=October 2007 | doi=10.1086/521555 | bibcode=2007AJ....134.1671M | s2cid=250820656 | doi-access=free }}</ref>
<ref name=Eggleton2008>{{citation | last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A. | title=A catalogue of multiplicity among bright stellar systems | journal=Monthly Notices of the Royal Astronomical Society | volume=389 | issue=2 | pages=869–879 | date=September 2008 | bibcode=2008MNRAS.389..869E | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | arxiv=0806.2878 | s2cid=14878976 | postscript=. }}</ref>
<ref name=Howe2009>{{citation | last1=Howe | first1=K. S. | last2=Clarke | first2=C. J. | title=An analysis of v sin (i) correlations in early-type binaries | journal=[[Monthly Notices of the Royal Astronomical Society]] | volume=392 | issue=1 | pages=448–454 |date=January 2009 | postscript=. | doi=10.1111/j.1365-2966.2008.14073.x | bibcode=2009MNRAS.392..448H | doi-access=free }}</ref>
<ref name=deBruijne2012>{{citation | last1=de Bruijne | first1=J. H. J. | last2=Eilers | first2=A.-C. | title=Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project | journal=Astronomy & Astrophysics | volume=546 | id=A61 | pages=14 | date=October 2012 | doi=10.1051/0004-6361/201219219 | bibcode=2012A&A...546A..61D | arxiv=1208.3048 | s2cid=59451347 | postscript=. }}</ref>
<ref name=Wraight2012>{{citation | title=A photometric study of chemically peculiar stars with the STEREO satellites - I. Magnetic chemically peculiar stars | last1=Wraight | first1=K. T. | last2=Fossati | first2=L. | last3=Netopil | first3=M. | last4=Paunzen | first4=E. | last5=Rode-Paunzen | first5=M. | last6=Bewsher | first6=D. | last7=Norton | first7=A. J. | last8=White | first8=Glenn J. | journal=Monthly Notices of the Royal Astronomical Society | volume=420 | issue=1 | pages=757–772 | date=February 2012 | doi=10.1111/j.1365-2966.2011.20090.x | doi-access=free | bibcode=2012MNRAS.420..757W | arxiv=1110.6283 | s2cid=14811051 | display-authors=1 | postscript=. }}</ref>
<ref name=SIMBAD>{{cite simbad | title=mu. Lib | accessdate=2017-01-24 | postscript=. }}</ref>
</references>
{{Stars of Libra|state=collapsed}}
[[Category:A-type main-sequence stars]] [[Category:Am stars]] [[Category:Libra (constellation)]] [[Category:Bayer objects|Libra, Mu]] [[Category:Durchmusterung objects|BD-13 3986]] [[Category:Henry Draper Catalogue objects|130559]] [[Category:Hipparcos objects|072489]] [[Category:Bright Star Catalogue objects|5523]] [[Category:Ap stars]]