Lambda Lyrae
{{short description|Suspected binary star system in the constellation Lyra}}
{{Starbox begin}}
{{Starbox observe
| epoch = J2000.0
| constell = Lyra
}}
{{Starbox character
}}
{{Starbox astrometry
| radial_v = {{Val|-17.69|0.02}}
| parallax = 2.4502
| p_error = 0.2016
| absmag_v = {{val|-3.75|+0.65|-0.50}}
}}
{{Starbox detail
| radius = {{Val|104.74|8.84}}
| luminosity = {{Val|3561|611|fmt=commas}}
| temperature = {{val|4361|68|fmt=commas}}
| rotational_velocity = {{val|3.2|1.0}}
}}
{{Starbox catalog
| names = {{odlist | B=λ Lyr | F=15 Lyrae | BD=+31°3424 | HD=176670 | HIP=93279 | HR=7192 | SAO=67682 }}
}}
{{Starbox reference
| Simbad = lam+Lyr
}}
{{Starbox end}}
λ Lyrae, Latinized as Lambda Lyrae, is a suspected binary star system in the northern constellation of Lyra. It is an orange-hued point of light that is dimly visible to the naked eye with an apparent visual magnitude of 4.94. The system is located approximately 1,300 light years distant from the Sun based on parallax, but is drifting closer with a radial velocity of −17.7 km/s.
The visible component is an aging giant star with a stellar classification of K2.5III:Ba0.5 and an estimated age of around 58 million years. The suffix notation indicates this is a mild barium star and hence it may have a white dwarf companion, while the colon indicates there is some uncertainty about the class. Having exhausted the supply of hydrogen at its core, it has cooled and expanded off the main sequence, and now has 105 times the radius of the Sun. The star has six times the mass of the Sun and is radiating over 4,300 times the Sun's luminosity from its swollen photosphere at an effective temperature of 4,361 K.
References
{{reflist|refs=
{{cite DR2|2043600522402116352}}
| title=Lam Lyr | accessdate=2019-09-17}}
| last1=Keenan | first1=Philip C. | last2=McNeil | first2=Raymond C.
| title=The Perkins Catalog of Revised MK Types for the Cooler Stars
| journal=The Astrophysical Journal Supplement Series
| volume=71 | pages=245 | year=1989
| doi=10.1086/191373 | bibcode=1989ApJS...71..245K }}
| display-authors=1
| last1=Carney | first1=Bruce W.
| last2=Gray | first2=David F.
| last3=Yong | first3=David
| last4=Latham | first4=David W.
| last5=Manset | first5=Nadine
| last6=Zelman | first6=Rachel
| last7=Laird | first7=John B.
| title=Rotation and Macroturbulence in Metal-Poor Field Red Giant and Red Horizontal Branch Stars
| journal=The Astronomical Journal
| volume=135 | issue=3 | pages=892–906 |date=March 2008
| doi=10.1088/0004-6256/135/3/892
| bibcode=2008AJ....135..892C
| arxiv = 0711.4984
| s2cid=2756572 | postscript=.
}}
| display-authors=1
| last1 = Famaey | first1 = B.
| last2 = Jorissen | first2 = A.
| last3 = Luri | first3 = X.
| last4 = Mayor | first4 = M.
| last5 = Udry | first5 = S.
| last6 = Dejonghe | first6 = H.
| last7 = Turon | first7 = C.
| title = Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters
| journal = Astronomy and Astrophysics
| volume = 430 | pages = 165–186 | date = 2005
| doi = 10.1051/0004-6361:20041272
| bibcode = 2005A&A...430..165F
| postscript=.
|arxiv = astro-ph/0409579 | s2cid = 17804304 }}
| last1=Jennens | first1=P. A.
| last2=Helfer | first2=H. L.
| title=A new photometric metal abundance and luminosity calibration for field G and K giants
| journal=Monthly Notices of the Royal Astronomical Society
| volume=172 | pages=667–679 |date=September 1975
| issue=3
| bibcode=1975MNRAS.172..667J
| doi=10.1093/mnras/172.3.667
| postscript=.
| doi-access=free
}}
| last1=Tetzlaff | first1=N.
| last2=Neuhäuser | first2=R.
| last3=Hohle | first3=M. M.
| title=A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun
| doi=10.1111/j.1365-2966.2010.17434.x
| journal=Monthly Notices of the Royal Astronomical Society
| volume=410 | pages=190–200 | year=2011
| issue=1
| doi-access=free
| arxiv=1007.4883
| bibcode=2011MNRAS.410..190T
| s2cid=118629873
| 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 | postscript=. }}
| last1=Lu | first1=Phillip K.
| title=Taxonomy of barium stars
| journal=Astronomical Journal | postscript=.
| volume=101 | pages=2229 | year=1991
| bibcode=1991AJ....101.2229L | doi=10.1086/115845 | doi-access=free }}
{{Cite journal |last1=van Belle |first1=Gerard T. |last2=von Braun |first2=Kaspar |last3=Ciardi |first3=David R. |last4=Pilyavsky |first4=Genady |last5=Buckingham |first5=Ryan S. |last6=Boden |first6=Andrew F. |last7=Clark |first7=Catherine A. |last8=Hartman |first8=Zachary |last9=van Belle |first9=Gerald |last10=Bucknew |first10=William |last11=Cole |first11=Gary |date=2021-12-01 |title=Direct Measurements of Giant Star Effective Temperatures and Linear Radii: Calibration against Spectral Types and V - K Color |bibcode=2021ApJ...922..163V |journal=The Astrophysical Journal |volume=922 |issue=2 |pages=163 |doi=10.3847/1538-4357/ac1687 |doi-access=free |arxiv=2107.09205 |issn=0004-637X}} [https://vizier.cds.unistra.fr/viz-bin/VizieR?-source=J/ApJ/922/163&Name=HD176670 Lambda Lyrae's database entry] at VizieR.
}}
{{Stars of Lyra}}