View source for 61 Leonis

{{Short description|Binary star in the constellation Leo}}
{{about|p<sup>2</sup> Leonis|other stars with this Bayer designation|p Leonis}}
{{Starbox begin
 | name = 61 Leonis
}}
{{Starbox observe
 | epoch = J2000
 | constell = [[Leo (constellation)|Leo]]
 | ra = {{RA|11|01|49.67462}}<ref name=vanLeeuwen2007/>
 | dec = {{DEC|-02|29|04.5007}}<ref name=vanLeeuwen2007/>
 | appmag_v = 4.73<ref name=Anderson2012/>
}}
{{Starbox character
 | type = [[asymptotic giant branch|AGB]]<ref name=eggen1992/>
 | class = M0&nbsp;III<ref name=perkins1989/>
 | b-v = {{Val|+1.593|0.059}}<ref name=Anderson2012/>
 | u-b = 
 | variable = suspected<ref name=nsv/>
}}
{{Starbox astrometry
 | radial_v = {{Val|−12.7|0.3}}<ref name=deBruijne2012/>
 | prop_mo_ra = +9.76<ref name=vanLeeuwen2007/>
 | prop_mo_dec = −35.56<ref name=vanLeeuwen2007/>
 | parallax = 5.58
 | p_error = 0.24
 | parallax_footnote = <ref name=vanLeeuwen2007/>
 | absmag_v = −1.53<ref name=Anderson2012/>
}}
{{Starbox detail
 | source = 
 | mass = 
 | radius = 74.5<ref name=lang2006/>
 | luminosity = 1,377.86<ref name=Anderson2012/>
 | gravity = {{Val|1.25|0.23}}<ref name=Prugniel2011/>
 | temperature = {{Val|3864|30|fmt=commas}}<ref name=Prugniel2011/>
 | metal_fe = {{Val|0.07|0.07}}<ref name=Prugniel2011/>
 | rotational_velocity = 
 | age_myr = 
}}
{{Starbox catalog
 | names = {{odlist | B=p<sup>2</sup> Leo | F=61 Leo | BD=-01° 2471 | FK5=2879 | HD=95578 | HIP=53907 | HR=4299 | SAO=137947 | NSV=5059 }}<ref name=SIMBAD/>
}}
{{Starbox reference
 | Simbad = 61+Leo
}}
{{Starbox end}}

'''61 Leonis''' is a possible [[binary star]]<ref name=Eggleton2008/> system in the [[zodiac]] [[constellation]] of [[Leo (constellation)|Leo]]. It is faintly visible to the naked eye, having an [[apparent visual magnitude]] of 4.73.<ref name=Anderson2012/> The star is moving closer to the Sun with a heliocentric [[radial velocity]] of −12.7&nbsp;km/s.<ref name=deBruijne2012/> It is located roughly 580&nbsp;[[light-year]]s from the Sun, as determined from its annual [[stellar parallax|parallax shift]] of {{Val|5.58|ul=mas}}.<ref name=vanLeeuwen2007/>

This is an [[stellar evolution|evolved]] [[red giant]] star with a [[stellar classification]] of M0&nbsp;III<ref name=perkins1989/> that Eggen (1992) listed as being on the [[asymptotic giant branch]] (AGB).<ref name=eggen1992/> It is a marginal [[barium star]], showing an enhanced abundance of [[s-process]] elements in its outer atmosphere. This material may have been acquired during a previous [[mass transfer]] from a now [[white dwarf]] companion, or self-enriched by a [[dredge-up]] during the AGB process.<ref name=gomez1997/> The measured [[angular diameter]] after correctly for [[limb darkening]] is {{Val|3.87|0.04|ul=mas}},<ref name=Richichi2005/> which, at the estimated distance of this system yields a physical size of about 74.5 times the [[radius of the Sun]].<ref name=lang2006/>

61 Leonis is a suspected variable star with [[apparent magnitude]] changing between 4.69 and 4.79.<ref name=nsv/> The variability was reported in a 1966 [[Photometry (optics)|photometric]] survey, but has not been confirmed by more recent photometry.<ref name=cousins/>

==References==
{{reflist|refs=

<ref name=cousins>{{cite journal|bibcode=1966RGOB..122...59C|title=Fabry photometry of bright southern stars|journal=Royal Greenwich Observatory Bulletins|volume=122|pages=59|author=A. W. J. Cousins|year=1966}}</ref>

<ref name=nsv>{{cite journal|bibcode=2009yCat....102025S|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)|journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S|volume=1|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}</ref>

<ref name=SIMBAD>{{cite simbad | title=61 Leo | access-date=2018-03-01 }}</ref>

<ref name=vanLeeuwen2007>{{citation
 | title=Validation of the new Hipparcos reduction
 | last1=van Leeuwen | first1=F. | postscript=.
 | journal=Astronomy and Astrophysics
 | volume=474 | issue=2 | pages=653–664 | year=2007
 | arxiv=0708.1752 | bibcode=2007A&A...474..653V
 | doi=10.1051/0004-6361:20078357 | s2cid=18759600 }}</ref>

<ref name=Anderson2012>{{citation
 | title=XHIP: An extended hipparcos compilation
 | last1=Anderson | first1=E. | last2=Francis | first2=Ch.
 | journal=Astronomy Letters
 | volume=38 | issue=5 | pages=331 | year=2012
 | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015
 | arxiv=1108.4971 | s2cid=119257644 | postscript=. }}</ref>

<ref name=eggen1992>{{citation
 | title=Asymptotic giant branch stars near the sun
 | last1=Eggen | first1=O. J. | postscript=.
 | journal=The Astronomical Journal
 | volume=104| pages=275 | year=1992
 | doi=10.1086/116239 | bibcode=1992AJ....104..275E }}</ref>

<ref name=gomez1997>{{citation
 | display-authors=1 | last1=Gomez | first1=A. E.
 | last2=Luri | first2=X. | last3=Grenier | first3=S.
 | last4=Prevot | first4=L. | last5=Mennessier | first5=M. O.
 | last6=Figueras | first6=F. | last7=Torra | first7=J.
 | title=Absolute magnitudes and kinematics of barium stars
 | journal=Astronomy and Astrophysics
 | volume=319 | pages=881 | year=1997
 | bibcode=1997A&A...319..881G | postscript=. }}</ref>

<ref name=Richichi2005>{{citation
 | display-authors=1 | last1=Richichi | first1=A.
 | last2=Percheron | first2=I. | last3=Khristoforova | first3=M.
 | title=CHARM2: An updated Catalog of High Angular Resolution Measurements
 | journal=Astronomy and Astrophysics
 | volume=431 | issue=2 | pages=773–777 | date=February 2005
 | doi=10.1051/0004-6361:20042039 | bibcode=2005A&A...431..773R | doi-access=free }}</ref>

<ref name=lang2006>{{citation
 | first1=Kenneth R. | last1=Lang
 | title=Astrophysical formulae | volume=1
 | series=Astronomy and astrophysics library
 | edition=3rd | publisher=[[Birkhäuser]]
 | date=2006 | isbn=3-540-29692-1
 | url=https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41 }}. The radius (R<sub>*</sub>) is given by:
:<math>\begin{align} 2\cdot R_*
 & = \frac{(179\cdot 3.87\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\
 & \approx 149\cdot R_{\bigodot}
\end{align}</math></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
 | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | bibcode=2008MNRAS.389..869E
 | postscript=. | arxiv=0806.2878 | s2cid=14878976 }}</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=Prugniel2011>{{citation
 | title=The atmospheric parameters and spectral interpolator for the MILES stars
 | journal=Astronomy & Astrophysics
 | volume=531 | pages=A165 | year=2011
 | display-authors=1 | last1=Prugniel | first1=Ph.
 | last2=Vauglin | first2=I. | last3=Koleva | first3=M.
 | doi=10.1051/0004-6361/201116769 | arxiv=1104.4952
 | bibcode=2011A&A...531A.165P | s2cid=54940439
 }}</ref>

<ref name=perkins1989>{{citation
 | title=The Perkins catalog of revised MK types for the cooler stars
 | last1=Keenan | first1=Philip C. | last2=McNeil | first2=Raymond C.
 | journal=Astrophysical Journal Supplement Series
 | volume=71 | pages=245 | year=1989
 | bibcode=1989ApJS...71..245K | doi=10.1086/191373 }}</ref>

}}

{{Stars of Leo}}

{{DEFAULTSORT:61 Leonis}}
[[Category:M-type giants]]
[[Category:Suspected variables]]
[[Category:Barium stars]]
[[Category:Leo (constellation)]]
[[Category:Bayer objects|Leo, p2]]
[[Category:Durchmusterung objects]]
[[Category:Flamsteed objects|Leonis, 61]]
[[Category:Henry Draper Catalogue objects|095578]]
[[Category:Hipparcos objects|053907]]
[[Category:Bright Star Catalogue objects|4299]]