{{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=37 Librae |x=330|y=225 }} | caption = Location of 37 Librae (circled in red) }} {{Starbox observe | epoch = J2000.0 | constell = [[Libra (constellation)|Libra]] | pronounce = | ra = {{RA|15|34|10.70209}}<ref name=vanLeeuwen2007/> | dec = {{DEC|−10|03|52.3063}}<ref name=vanLeeuwen2007/> | appmag_v = 4.61<ref name=Anderson2012/> }} {{Starbox character | type = subgiant<ref name=Snowden2005/> | class = K1III–IV<ref name=perkins1989/> | b-v = {{Val|1.00|0.03}}<ref name=Anderson2012/> | u-b = | variable = }} {{Starbox astrometry | radial_v = {{Val|+49.25|0.08}}<ref name=jofre2015/> | prop_mo_ra = +307.63<ref name=vanLeeuwen2007/> | prop_mo_dec = −234.51<ref name=vanLeeuwen2007/> | parallax = 34.57 | p_error = 0.22 | parallax_footnote = <ref name=vanLeeuwen2007/> | absmag_v = 2.30<ref name=Anderson2012/> }} {{Starbox detail | source = <ref name=jofre2015/> | mass = {{Val|1.38|0.10}} | radius = {{Val|5.133|0.043}}<ref name=Rains2020/> | gravity = {{Val|3.19|0.06}} | metal_fe = {{Val|0.02|0.04}} | luminosity = {{val|12.71|0.69}}<ref name=Rains2020/> | temperature = {{Val|4809|62|fmt=commas}}<ref name=Rains2020/> | rotational_velocity = {{Val|2.02|0.33}} | age_gyr = {{Val|3.39|0.80}} }} {{Starbox catalog | names = {{odlist| F=37 Lib | BD=-09°4171 | FK5=1409 | GC=20914 | HD=138716 | HIP=76219 | HR=5777 | SAO=140609 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = 37+Lib }} {{Starbox end}}
'''37 Librae''' is a single<ref name=Eggleton2008/> [[star]] in the southern [[zodiac]] [[constellation]] of [[Libra (constellation)|Libra]]. It is visible to the naked eye as a faint, orange-hued star with an [[apparent visual magnitude]] of 4.61.<ref name=Anderson2012/> The star is located 94 [[light year]]s from the Sun based on [[stellar parallax|parallax]], and is drifting further away with a [[radial velocity]] of +49 km/s.<ref name=jofre2015/>
This is an [[stellar evolution|evolving]] [[subgiant star]]<ref name=Snowden2005/> with a [[stellar classification]] of K1 III–IV,<ref name=perkins1989/> where the [[luminosity class]] indicates the [[stellar spectrum|spectrum]] displays blended traits of a subgiant and a [[giant star]]. It is an estimated 3.4 billion years old with 1.4 times the [[mass of the Sun]].<ref name=jofre2015/> Having the supply of hydrogen at its [[stellar core|core]] all but exhausted, the star is starting to expand; currently it has five times the girth of the Sun. It is radiating 12.7 times the [[Sun's luminosity]] from its enlarged [[photosphere]] at an [[effective temperature]] of 4,809 K.<ref name=Rains2020/> At this temperature, 37 Librae glows with the hue of a [[K-type star]].<ref name=csiro/>
==References== <references>
<ref name=SIMBAD>{{cite simbad | title=37 Lib | access-date=2019-07-17 }}</ref>
<ref name=Anderson2012>{{cite journal | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | title=XHIP: An extended hipparcos compilation | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | arxiv=1108.4971 | doi=10.1134/S1063773712050015 | s2cid=119257644 }}</ref>
<ref name=Rains2020>{{cite journal | title=Precision angular diameters for 16 southern stars with VLTI/PIONIER | display-authors=1 | last1=Rains | first1=Adam D. | last2=Ireland | first2=Michael J. | last3=White | first3=Timothy R. | last4=Casagrande | first4=Luca | last5=Karovicova | first5=I. | journal=Monthly Notices of the Royal Astronomical Society | volume=493 | issue=2 | pages=2377–2394 | date=April 2020 | arxiv=2004.02343 | bibcode=2020MNRAS.493.2377R | doi=10.1093/mnras/staa282 | doi-access=free }}</ref>
<ref name=vanLeeuwen2007>{{citation | title=Validation of the new Hipparcos reduction | last=van Leeuwen | first=F. | postscript=. | 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 }}</ref>
<ref name=perkins1989>{{citation | last1=Keenan | first1=Philip C. | last2=McNeil | first2=Raymond C. | title=The Perkins catalog of revised MK types for the cooler stars | journal=Astrophysical Journal Supplement Series | volume=71 | pages=245 | year=1989 | postscript=. | bibcode=1989ApJS...71..245K | doi=10.1086/191373 }}</ref>
<ref name=csiro>{{citation | title=The Colour of Stars | date=December 21, 2004 | work=Australia Telescope, Outreach and Education | publisher=Commonwealth Scientific and Industrial Research Organisation | url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html | accessdate=2012-01-16 | archive-date=2013-12-03 | archive-url=https://web.archive.org/web/20131203222826/http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html | url-status=dead }}</ref>
<ref name=jofre2015>{{citation | last1=Jofré | first1=E.| last2=Petrucci| first2=R. | last3=Saffe| first3=C. | last4=Saker | first4=L. | last5=de la Villarmois | first5=E. Artur | last6=Chavero | first6=C. | last7= Gómez | first7=M. | last8= Mauas | first8=P. J. D. | title=Stellar parameters and chemical abundances of 223 evolved stars with and without planets | display-authors=1 | journal=Astronomy & Astrophysics | volume=574 | id=A50 | year=2015 | postscript=. | bibcode= 2015A&A...574A..50J | doi=10.1051/0004-6361/201424474 | arxiv=1410.6422 | page=A50| s2cid=53666931}}</ref>
<ref name=Snowden2005>{{citation | postscript=. | title=Radial Velocities of Late-Type Field Subgiant Stars | last1=Snowden | first1=Michael S. | last2=Young | first2=Arthur | journal=The Astrophysical Journal Supplement Series | volume=157 | issue=1 | pages=126–137 | date=March 2005 | doi=10.1086/423711 | bibcode=2005ApJS..157..126S | doi-access=free }}</ref>
<ref name=Eggleton2008>{{citation | postscript=. | 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 | arxiv=0806.2878 | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | s2cid=14878976 }}</ref>
</references>
{{Stars of Libra}}
[[Category:K-type subgiants]] [[Category:Libra (constellation)]] [[Category:Durchmusterung objects|BD-09 4171]] [[Category:Flamsteed objects|Librae, 37]] [[Category:Henry Draper Catalogue objects|138716]] [[Category:Hipparcos objects|076219]] [[Category:Bright Star Catalogue objects|5777]]