Beta Aurigae

{{Short description|Binary star system in the northern constellation of Auriga}} {{Starbox begin | name = β Aurigae }} {{Starbox image | image= {{Location mark |image=Auriga constellation map.svg|alt=|float=center|width=240 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=β Aurigae |x=382|y=306 }} |caption=Location of β Aurigae (circled) }} {{Starbox observe | epoch = J2000.0 | constell = Auriga | ra = {{RA|05|59|31.72293}}<ref name=aaa474_2_653/> | dec = {{DEC|+44|56|50.7573}}<ref name=aaa474_2_653/> | appmag_v = {{val|1.89|-|1.98}}<ref name=gcvs/> (2.602 + 2.705)<ref name=Piccotti2020/> }} {{Starbox character | type = Main sequence<ref name=Dryomova2007/><ref name=Khaliullin2010/><ref name=Evans2023/> | class = {{nowrap|A1m IV + A1m IV}}<ref name=aaa467_3_1215/> | r-i = −0.01{{cn|date=May 2025}} | b-v = +0.03<ref name=clpl4_99/> | u-b = +0.05<ref name=clpl4_99/> | variable = Algol variable<ref name=gcvs/> }} {{Starbox astrometry | radial_v = −18.2<ref name=gcsrv/> | prop_mo_ra = −56.44 | prop_mo_dec = −0.95 | pm_footnote = <ref name=aaa474_2_653/> | parallax = 40.21 | p_error = 0.23 | parallax_footnote = <ref name=aaa474_2_653/> | absmag_v = 0.674 / 0.777<ref name=Piccotti2020/> }} {{Starbox orbit | reference = <ref name=aj142_1_6/> | period_unitless = 3.96004 days | axis =  | axis_unitless = {{val|0.08214|0.00015|fmt=none}}<ref name=Piccotti2020/> AU | eccentricity = 0.0 | inclination = 76.0 ± 0.4 | node =  | periastron = 54539.0162 ± 0.0003 reduced HJD | periarg = | k1 = {{val|108.053|0.099}} | k2 = {{val|110.911|0.098}} }} {{Starbox detail | component1 = β Aur Aa | mass = {{val|2.3885|0.0134}}<ref name=aj142_1_6/> | radius = {{val|2.762|0.017}}<ref name=aaa467_3_1215/> | luminosity = {{val|46.7|5.7|5.1}}<ref name=Piccotti2020/> | temperature = 8,985<ref name=Piccotti2020/> | metal_fe = | gravity = 3.93<ref name=aar18_1_2/> | rotational_velocity = 33<ref name="Nordstrom" /> | age_myr = {{val|400|-|500}}<ref name=aaa467_3_1215/> | component2 = β Aur Ab | mass2 = {{val|2.327|0.013}}<ref name=aj142_1_6/> | radius2 = {{val|2.568|0.017}}<ref name=aaa467_3_1215/> | luminosity2 = {{val|40|10|8}}<ref name=Piccotti2020/> | rotational_velocity2 = 34<ref name="Nordstrom" /> | temperature2 = 8,760<ref name=Piccotti2020/> | age_myr2 = {{val|400|-|500}}<ref name=aaa467_3_1215/> }} {{Starbox catalog | names = {{odlist | name=Menkalinan | B=β Aurigae | F=34 Aurigae | ADS=4556 | BD=+44 1328 | FK5=227 | HD=40183 | HIP=28360 | HR=2088 | SAO=40750 | WDS=J05595+4457Aa,Ab | GC=7543 | PPM=48617 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad=bet+Aur }} {{Starbox end}}

'''Beta Aurigae''' is a binary star<ref name=mnras389_2_869/> system in the northern constellation of Auriga. Its identifier is a Bayer designation that is Latinized from '''β Aurigae''', and abbreviated '''Beta Aur''' or '''β Aur'''. This star has the official name '''Menkalinan''', pronounced {{IPAc-en|m|ɛ|ŋ|'|k|æ|l|ɪ|n|æ|n}}.<ref name=Kunitzsch/><ref name="IAU-CSN"/> The combined apparent visual magnitude of the system is 1.9,<ref name=clpl4_99/> making it the second-brightest member of the constellation after Capella. Using the parallax measurements made during the Hipparcos mission, the distance to this star system can be estimated as {{Convert|81.1|ly|pc|abbr=off|lk=on}}, give or take a half-light-year margin of error.<ref name=aaa474_2_653/> It is drifting closer to the Sun with a radial velocity of −18 km/s.<ref name=gcsrv/>

Along their respective orbits around the Milky Way, Beta Aurigae and the Sun are closing in on each other, so that in around one million years it will become the brightest star in the night sky.<ref name=tomkin1998/> It is predicted to come as close as {{cvt|9.72|pc|ly|order=flip}} in 1.31 million years.<ref name=Bailer-Jones_2015/>

== Nomenclature == [[File:Astronomer Edward Charles Pickering's Harvard computers.jpg|thumb|left|Women computers at the Harvard College Observatory; on the wall is a graph of β Aurigae's varying brightness in December 1889.]]''β Aurigae'' is the star system's Bayer designation. The traditional name ''Menkalinan'' is derived from the Arabic '''منكب ذي العنان''' ''mankib ðī-l-‘inān'' "shoulder of the rein-holder". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)<ref name="WGSN"/> to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016<ref name="WGSN1">{{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/WGSN_bulletin1.pdf | title=Bulletin of the IAU Working Group on Star Names, No. 1 |access-date=28 July 2016}}</ref> included a table of the first two batches of names approved by the WGSN; which included ''Menkalinan'' for this star.

It is known as 五車三 (the Third Star of the Five Chariots) in traditional Chinese astronomy. {{clear left}}

== Properties == [[File:BetaAurLightCurve.png|thumb|left|A light curve for Beta Aurigae, plotted from data published by Southworth ''et al.'' (2007)<ref name=aaa467_3_1215/>]] Beta Aurigae is a binary star system, but it appears as a single star in the night sky. The two stars are metallic-lined stars belonging to the A-type stellar classification. Although the spectra have the luminosity class of a subgiant (IV),<ref name=aaa467_3_1215/> the components are still on the main sequence stage of evolution.<ref name=Dryomova2007/><ref name=Khaliullin2010/> This discrepancy arises from their nature as Am stars, which make them larger and more luminous than a "normal" star.<ref name=Evans2023/> A-type stars are hot and release a white hued light; these two stars burn brighter and with more heat than the Sun, which is a G2-type main sequence star. The pair constitute an eclipsing spectroscopic binary; the combined apparent magnitude varies over a period of 3.96 days between +1.89 and +1.94, as every 47.5 hours one of the stars partially eclipses the other from Earth's perspective.<ref name=aaa446_2_785/> The two stars are designated Aa and Ab in modern catalogues,<ref name=wds/><ref name=Piccotti2020/> but have also been referred to as components ''1'' and ''2'' or ''A'' and ''B''.<ref name=aj142_1_6/><ref name="Nordstrom" />

There is an 11th magnitude optical companion with a separation of {{val|187|ul="}} as of 2011, but increasing. It is also an A-class subgiant, but is an unrelated background star.<ref name=wds/>

At an angular separation of {{val|13.9|0.3|ul=arcseconds}} along a position angle of 155° is a companion star that is 8.5 magnitudes fainter than the primary. It may be the source of the X-ray emission from the vicinity.<ref name=mnras415_1_854/> The Beta Aurigae system is believed to be a stream member of the Ursa Major Moving Group.<ref name=aaa77_1_214/> {{clear left}}

== See also == * Algol * Capella * Alsephina

==References== <references> <ref name=wds>{{citation | postscript=. | display-authors=1 | last1=Mason | first1=Brian D. | last2=Wycoff | first2=Gary L. | last3=Hartkopf | first3=William I. | last4=Douglass | first4=Geoffrey G. | last5=Worley | first5=Charles E. | title=The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog | journal=The Astronomical Journal | volume=122 | issue=6 | pages=3466–3471 | date=December 2001 | doi=10.1086/323920| doi-access=free | bibcode=2001AJ....122.3466M }}</ref>

<ref name=gcvs>{{citation | postscript=. | display-authors=1 | last1=Samus | first1=N. N. | last2=Kazarovets | first2=E. V. | last3=Durlevich | first3=O. V. | last4=Kireeva | first4=N. N. | last5=Pastukhova | first5=E. N. | title=General Catalogue of Variable Stars | version=5.1 | journal=Astronomy Reports | year=2017 | volume=61 | issue=1 | pages=80–88 | bibcode=2017ARep...61...80S | s2cid=125853869 | doi=10.1134/S1063772917010085 }}</ref>

<ref name=aaa474_2_653>{{citation | postscript=. | first=F. | last=van Leeuwen |date=November 2007 | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 |arxiv = 0708.1752 | s2cid=18759600 }}</ref>

<ref name=clpl4_99>{{citation | postscript=. | display-authors=1 | last1=Johnson | first1=H. L. | last2=Iriarte | first2=B. | last3=Mitchell | first3=R. I. | last4=Wisniewskj | first4=W. Z. | title=UBVRIJKL photometry of the bright stars | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | pages=99 | year=1966 | bibcode=1966CoLPL...4...99J }}</ref>

<ref name="Nordstrom">{{citation | postscript=. | title=Radii and masses for beta Aurigae | journal=Astronomy and Astrophysics | volume=291 | issue=3 | pages=777–785 | year=1994 | last1=Nordstrom | first1=B. | last2=Johansen | first2=K. T. | bibcode=1994A&A...291..777N }}</ref>

<ref name=aar18_1_2>{{citation | postscript=. | display-authors=1 | last1=Torres | first1= G. | last2=Andersen | first2=J. | last3=Giménez | first3=A. | title=Accurate masses and radii of normal stars: modern results and applications | journal=The Astronomy and Astrophysics Review | volume=18 | issue=1–2 | pages=67–126 |date=February 2010 | doi=10.1007/s00159-009-0025-1 | bibcode=2010A&ARv..18...67T | arxiv=0908.2624 | s2cid=14006009 }}</ref>

<ref name=gcsrv>{{citation | postscript=. | last=Wilson | first=R. E. | year=1953 | title=General Catalogue of Stellar Radial Velocities | journal=Washington | publisher=Carnegie Institute of Washington D.C. | bibcode=1953GCRV..C......0W }}</ref>

<ref name=aj142_1_6>{{citation | postscript=. | display-authors=1 | last1=Behr | first1=Bradford B. | last2=Cenko | first2=Andrew T. | last3=Hajian | first3=Arsen R. | last4=McMillan | first4=Robert S. | last5=Murison | first5=Marc | last6=Meade | first6=Jeff | last7=Hindsley | first7=Robert | title=Stellar Astrophysics with a Dispersed Fourier Transform Spectrograph. II. Orbits of Double-lined Spectroscopic Binaries | journal=The Astronomical Journal | volume=142 | issue=1 | page=6 |date=July 2011 | doi=10.1088/0004-6256/142/1/6 | bibcode=2011AJ....142....6B |arxiv = 1104.1447 | s2cid=119099887 }}</ref>

<ref name=Evans2023>{{Cite journal |last1=Evans |first1=Nancy Remage |last2=Ferrari |first2=Mckenzie G. |last3=Kuraszkiewicz |first3=Joanna |last4=Silverberg |first4=Steven |last5=Nichols |first5=Joy |last6=Torres |first6=Guillermo |last7=Fischbach |first7=Makenzi |date=2023-08-17 |title=The Mass–Temperature Relation for B and Early A Stars Based on International Ultraviolet Explorer Spectra of Detached Eclipsing Binaries |journal=The Astronomical Journal |volume=166 |issue=3 |pages=109 |doi=10.3847/1538-3881/ace89b |doi-access=free |arxiv=2308.01374 |bibcode=2023AJ....166..109E |issn=0004-6256}}</ref>

<ref name=Khaliullin2010>{{Citation |last1=Khaliullin |first1=Kh F. |last2=Khaliullina |first2=A. I. |date=January 2010 |title=Synchronization and circularization in early-type binaries on main sequence |journal=Monthly Notices of the Royal Astronomical Society |language=en |volume=401 |issue=1 |pages=257–274 |doi=10.1111/j.1365-2966.2009.15630.x |doi-access=free |bibcode=2010MNRAS.401..257K |issn=0035-8711}}.</ref>

<ref name=Dryomova2007>{{Citation |last1=Dryomova |first1=G. N. |last2=Svechnikov |first2=M. A. |date=2007-04-01 |title=Effect of tidal evolution in determining the ages of eclipsing-variable early main sequence close binary systems |journal=Springer Nature |language=en |volume=50 |issue=2 |pages=239–253 |doi=10.1007/s10511-007-0023-9 |bibcode=2007Ap.....50..239D |issn=1573-8191}}.</ref>

<ref name=mnras389_2_869>{{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 | doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | bibcode=2008MNRAS.389..869E |arxiv = 0806.2878 | s2cid=14878976 }}</ref>

<ref name=SIMBAD>{{cite simbad | title=bet Aur | access-date=2012-07-18 }}</ref>

<ref name=mnras415_1_854>{{citation | postscript=. | display-authors=1 | last1=De Rosa | first1=R. J. | last2=Bulger | first2=J. | last3=Patience | first3=J. | last4=Leland | first4=B. | last5=Macintosh | first5=B. | last6=Schneider | first6=A. | last7=Song | first7=I. | last8=Marois | first8=C. | last9=Graham | first9=J. R. | last10=Bessell | first10=M. | last11=Doyon | first11=R. | title=The Volume-limited A-Star (VAST) survey - I. Companions and the unexpected X-ray detection of B6-A7 stars | journal=Monthly Notices of the Royal Astronomical Society | volume=415 | issue=1 | pages=854–866 |date=July 2011 | doi=10.1111/j.1365-2966.2011.18765.x | doi-access=free | bibcode=2011MNRAS.415..854D | arxiv=1103.4363 | s2cid=84181878 }}</ref>

<ref name=aaa467_3_1215>{{citation | postscript=. | display-authors=1 | last1=Southworth | first1=J. | last2=Bruntt | first2=H. | last3=Buzasi | first3=D. L. | title=Eclipsing binaries observed with the WIRE satellite. II. β Aurigae and non-linear limb darkening in light curves | journal=Astronomy and Astrophysics | volume=467 | issue=3 |date=June 2007 | pages=1215–1226 | doi=10.1051/0004-6361:20077184 | bibcode=2007A&A...467.1215S | arxiv=astro-ph/0703634 | s2cid=16446042 }}</ref>

<ref name="Piccotti2020">{{Citation | postscript=. | display-authors=1 |last1=Piccotti |first1=Luca |last2=Docobo |first2=José Ángel |last3=Carini |first3=Roberta |last4=Tamazian |first4=Vakhtang S. |last5=Brocato |first5=Enzo |last6=Andrade |first6=Manuel |last7=Campo |first7=Pedro P. |date=2020-02-01 |title=A study of the physical properties of SB2s with both the visual and spectroscopic orbits |journal=Monthly Notices of the Royal Astronomical Society |volume=492 |issue=2 |pages=2709–2721 |doi=10.1093/mnras/stz3616 |doi-access=free |bibcode=2020MNRAS.492.2709P |issn=0035-8711}} [https://vizier.cds.unistra.fr/viz-bin/VizieR?-source=J/MNRAS/492/2709&HD=40183 Menkalinan's database entry] at VizieR.</ref>

<ref name=aaa446_2_785>{{citation | postscript=. | display-authors=1 | last1=Malkov | first1=O. Yu. | last2=Oblak | first2=E. | last3=Snegireva | first3=E. A. | last4=Torra | first4=J. | title=A catalogue of eclipsing variables | journal=Astronomy and Astrophysics | volume=446 | issue=2 |date=February 2006 | pages=785–789 | doi=10.1051/0004-6361:20053137 | bibcode=2006A&A...446..785M | doi-access=free | hdl=10995/73280 | hdl-access=free }}</ref>

<ref name=aaa77_1_214>{{citation | postscript=. | last1=Giannuzzi | first1=M. A. | title=On the eclipsing binaries of the Ursa Major stream | journal=Astronomy and Astrophysics | volume=77 | issue=1–2 | pages=214–222 |date=August 1979 | bibcode=1979A&A....77..214G }}</ref>

<ref name=Kunitzsch>{{citation | postscript=. | last1=Kunitzsch |first1=Paul | last2=Smart |first2=Tim | date=2006 | edition=2nd rev. | title=A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations | publisher=Sky Pub | location=Cambridge, Massachusetts | isbn=978-1-931559-44-7 }}</ref>

<ref name="IAU-CSN">{{citation | postscript=. | url=http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt | title=IAU Catalog of Star Names | publisher=International Astronomical Union | access-date=28 July 2016 }}</ref>

<ref name=tomkin1998>{{citation | postscript=. | last=Tomkin | first=Jocelyn | date=April 1998 | title=Once and Future Celestial Kings | journal=Sky and Telescope | volume=95 | issue=4 | pages=59–63 | bibcode=1998S&T....95d..59T }} – based on computations from HIPPARCOS data. (The calculations exclude stars whose distance or proper motion is uncertain.) [ftp://tlgleonid.asuscomm.com/HITACHI/BOOK_ASTRO/S&T/SkyandTelescope_1998%20-%20astronomy/04/199804059063.pdf PDF]{{dead link|date=May 2025|bot=medic}}{{cbignore|bot=medic}}</ref>

<ref name="WGSN">{{citation | postscript=. | title=IAU Working Group on Star Names (WGSN) | publisher=International Astronomical Union | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | access-date=22 May 2016 | archive-date=10 June 2016 | archive-url=https://web.archive.org/web/20160610172014/https://www.iau.org/science/scientific_bodies/working_groups/280/ | url-status=dead }}</ref>

<ref name=Bailer-Jones_2015>{{citation | postscript=. | title=Close encounters of the stellar kind | last=Bailer-Jones | first=C. A. L. | journal=Astronomy & Astrophysics | volume=575 | id=A35 | pages=13 | date=March 2015 | doi=10.1051/0004-6361/201425221 | arxiv=1412.3648 | bibcode=2015A&A...575A..35B | s2cid=59039482 }}</ref> </references>

== External links == * [https://web.archive.org/web/20060220234451/http://www.astro.uiuc.edu/~kaler/sow/menkalinan.html Menkalinan] * [http://aladin.u-strasbg.fr/AladinPreview?-c=05+59+31.7229%2B44+56+50.758&ident=V*+bet+Aur&submit=Aladin+previewer Image Beta Aurigae] * [http://webviz.u-strasbg.fr/viz-bin/VizieR-S?CCDM%20J05596%2b4457A CCDM J05596+4457] Catalog * [http://adsabs.harvard.edu/abs/1994A&A...291..777N Smithsonian/NASA Astrophysics Data System] * [https://astrojolo.com/spectroscopy/menkalinan-spectroscopic-binary-star/ Menkalinan - spectroscopic binary star] * [https://www.baader-planetarium.com/de/downloads/dl/file/id/1419/product/1481/presentation_radial_velocity_measurement_menkalinan_the_spectroscopic_binary_by_miroslav_matousek.pdf Menkalinan - Beta Aurigae, the spectroscopic eclipsing binary star]

{{Stars of Auriga}}

Category:M-type main-sequence stars Category:A-type main-sequence stars Category:Am stars Category:Algol variables Category:Triple star systems Category:Ursa Major moving group  Category:Auriga Aurigae, Beta 2088 BD+44 1328 Aurigae, 34 040183 028360 Menkalinan Category:Brightest stars