{{short description|Star in the constellation Ursa Major}} {{Starbox begin}} {{Starbox image | image ={{Location map|100x100 |AlternativeMap=Ursa Major IAU.svg |caption= |alt=Diagram showing star positions and boundaries of the Ursa Major constellation and its surroundings |width=320 |lat=45.85 |long=59.7 |mark=Cercle rouge 100%.svg | marksize=12 |float=center }}| caption=Location of λ Ursae Majoris (circled) }} {{Starbox observe | epoch = J2000 | ra = {{RA|10|17|05.78287}}<ref name=aaa474_2_653/> | dec = {{DEC|+42|54|51.6808}}<ref name=aaa474_2_653/> | appmag_v = +3.45<ref name=clpl4_99/> | constell = Ursa Major }} {{Starbox character | type = main sequence<ref name=zorec2012/> | class = A2 IV<ref name=aj74_375/> | b-v = +0.03<ref name=clpl4_99/> | u-b = +0.06<ref name=clpl4_99/> | variable = }} {{Starbox astrometry | radial_v = +18.1<ref name=rgcrv/> | prop_mo_ra = –180.65<ref name=aaa474_2_653/> | prop_mo_dec = –46.07<ref name=aaa474_2_653/> | parallax = 23.72 | p_error = 0.78 | parallax_footnote = <ref name=aaa474_2_653/> | absmag_v = +0.10<ref name=Eggen1998/> }} {{Starbox detail | mass = 2.11<ref name=David2015/> | radius = 2.3<ref name=aass85_3_1015/> | luminosity = 37<ref name=aass85_3_1015/> | temperature = {{Val|9247|314|fmt=commas}}<ref name=David2015/> | metal_fe = +0.20<ref name=aaa294_2_536/> | rotation = | rotational_velocity = 50<ref name=aaa463_2_671/> | gravity ={{Val|3.76|0.14}}<ref name=David2015/> | age_myr = 380<ref name=David2015/> }} {{Starbox catalog | names = {{odlist |name=Tania Borealis |B=λ Ursae Majoris, λ UMa, Lambda UMa |F=33 Ursae Majoris |BD=+43°2005 |FK5=383 |GC=14113, |HD=89021 |HIP=50372 |HR=4033 |PPM=51795 |SAO=43268 }}<ref name=SIMBAD/> }} {{Starbox reference |Simbad=lam+UMa }} {{Starbox end}}
'''Lambda Ursae Majoris''' ('''λ Ursae Majoris''', abbreviated '''Lambda UMa''', '''λ UMa'''), formally named '''Tania Borealis''' {{IPAc-en|'|t|ei|n|i|@|_|,|b|Q|r|i|'|æ|l|I|s}},<ref name=Kunitzsch>{{cite book |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">{{cite web | url=http://www.pas.rochester.edu/~emamajek/WGSN/IAU-CSN.txt | title=IAU Catalog of Star Names |accessdate=28 July 2016}}</ref> is a star in the northern circumpolar constellation of Ursa Major.
==Properties== This star has an apparent visual magnitude of +3.45,<ref name=clpl4_99/> making it one of the brighter members of the constellation. The distance to this star has been measured directly using the parallax technique, which yields a value of roughly {{Convert|138|ly|pc|abbr=off|lk=on}} with a 4% margin of error. The stellar classification of Lambda Ursae Majoris is A2 IV,<ref name=aj74_375/> with the luminosity class of 'IV' indicating that, after 410 million years<ref name=apj653_1_675/> on the main sequence, this star is in the process of evolving into a giant star as the supply of hydrogen at its core becomes exhausted. Compared to the Sun it has 240% of the mass and 230% of the Sun's radius, but is radiating 37 times as much luminosity.<ref name=aass85_3_1015/> This energy is being emitted from the star's outer atmosphere at an effective temperature of 9,280 K,<ref name=aaa294_2_536/> giving it the characteristic white-hot glow of an A-type star.<ref name=csiro/>
==Nomenclature== ''λ Ursae Majoris'' (Latinised to ''Lambda Ursae Majoris'') is the star's Bayer designation.
It bore the traditional names ''Tania'' (shared with Mu Ursae Majoris) and ''Tania Borealis''. ''Tania'' comes from the Arabic phrase {{Transliteration|ar|''Al Fiḳrah al Thānia''}} 'the Second Spring (of the Gazelle)'.<ref name=rhallen1899>[https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Ursa_Major*.html Richard Hinckley Allen :Star Names — Their Lore and Meaning - Ursa Major, the Greater Bear]</ref> and ''Borealis'' (originally ''borealis''<ref>Piazzi, G., ''The Palermo Catalogue'', Palermo, 1814.</ref>) is Latin for 'the north side'. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)<ref name="WGSN">{{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN) | accessdate=22 May 2016 | archive-date=15 July 2018 | archive-url=https://web.archive.org/web/20180715111556/https://www.iau.org/science/scientific_bodies/working_groups/280/ | url-status=dead }}</ref> 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 |accessdate=28 July 2016}}</ref> included a table of the first two batches of names approved by the WGSN; which included ''Tania Borealis'' for this star.
In Chinese, {{lang|zh|三台}} ({{lang|zh-Latn|Sān Tái}}), meaning ''Three Steps'', refers to an asterism consisting of Lambda Ursae Majoris, Iota Ursae Majoris, Kappa Ursae Majoris, Mu Ursae Majoris, Nu Ursae Majoris and Xi Ursae Majoris. Consequently, the Chinese name for Lambda Ursae Majoris itself is {{lang|zh|中台一}} ({{lang|zh-Latn|Zhōng Tái yī}}, {{langx|en|Star of First Middle Step}}).<ref>{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0606/ap060621.html (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 21 日] {{Webarchive|url=https://web.archive.org/web/20160303180027/http://aeea.nmns.edu.tw/2006/0606/ap060621.html |date=2016-03-03 }}</ref>
== References == <references> <ref name=aaa474_2_653>{{citation | 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=David2015>{{citation | last1=David | first1=Trevor J. | last2=Hillenbrand | first2=Lynne A. | title=The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets | journal=The Astrophysical Journal | volume=804 | issue=2 | pages=146 | year=2015 | bibcode=2015ApJ...804..146D | doi=10.1088/0004-637X/804/2/146 | arxiv=1501.03154 | s2cid=33401607 | postscript=. }}</ref>
<ref name=aaa294_2_536>{{citation | last1=Hill | first1=G. M. | title=Compositional differences among the A-type stars. 2: Spectrum synthesis up to V sin i = 110 km/s | journal=Astronomy and Astrophysics | volume=294 | issue=2 | pages=536–546 |date=February 1995 | bibcode=1995A&A...294..536H }}</ref>
<ref name=aj74_375>{{citation | display-authors=1 | last1=Cowley | first1=A. | last2=Cowley | first2=C. | last3=Jaschek | first3=M. | last4=Jaschek | first4=C. | title=A study of the bright A stars. I. A catalogue of spectral classifications | journal=Astronomical Journal | volume=74 | pages=375–406 |date=April 1969 | doi=10.1086/110819 | bibcode=1969AJ.....74..375C }}</ref>
<ref name=rgcrv>{{citation | last1=Evans | first1=D. S. | date=June 20–24, 1966 | editor1-last=Batten | editor1-first=Alan Henry | editor2-last=Heard | editor2-first=John Frederick | contribution=The Revision of the General Catalogue of Radial Velocities | title=Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 | volume=30 | page=57 | location=University of Toronto | publisher=International Astronomical Union | bibcode=1967IAUS...30...57E }}</ref>
<ref name=aaa463_2_671>{{citation | last1=Royer | first1=F. | last2=Zorec | first2=J. | last3=Gómez | first3=A. E. | title=Rotational velocities of A-type stars. III. Velocity distributions | journal=Astronomy and Astrophysics | volume=463 | issue=2 | pages=671–682 |date=February 2007 | doi=10.1051/0004-6361:20065224 | bibcode=2007A&A...463..671R |arxiv = astro-ph/0610785 | s2cid=18475298 }}</ref>
<ref name=clpl4_99>{{citation | 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 | date=1966 | page=99 | bibcode=1966CoLPL...4...99J }}</ref>
<ref name=apj653_1_675>{{citation | display-authors=1 | last1=Su | first1=K. Y. L. | last2=Rieke | first2=G. H. | last3=Stansberry | first3=J. A. | last4=Bryden | first4=G. | last5=Stapelfeldt | first5=K. R. | last6=Trilling | first6=D. E. | last7=Muzerolle | first7=J. | last8=Beichman | first8=C. A. | last9=Moro-Martin | first9=A. | title=Debris Disk Evolution around A Stars | journal=The Astrophysical Journal | volume=653 | issue=1 | pages=675–689 |date=December 2006 | doi=10.1086/508649 | bibcode=2006ApJ...653..675S |arxiv = astro-ph/0608563 | s2cid=14116473 }}</ref>
<ref name=aass85_3_1015>{{citation | last1=Malagnini | first1=M. L. | last2=Morossi | first2=C. | title=Accurate absolute luminosities, effective temperatures, radii, masses and surface gravities for a selected sample of field stars | journal=Astronomy and Astrophysics Supplement Series | volume=85 | issue=3 | pages=1015–1019 |date=November 1990 | bibcode=1990A&AS...85.1015M }}</ref>
<ref name=SIMBAD>{{citation | url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Lambda+Ursae+Majoris | title=lam UMa -- High proper-motion Star | work=SIMBAD | publisher=Centre de Données astronomiques de Strasbourg | accessdate=2012-01-20 }}</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 |url-status=dead |archiveurl=https://web.archive.org/web/20120318151427/http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html |archivedate=March 18, 2012 }}</ref>
<ref name=Eggen1998>{{citation | title=The Age Range of Hyades Stars | last1=Eggen | first1=Olin J. | postscript=. | journal=The Astronomical Journal | volume=116 | issue=1 | pages=284–292 | date=July 1998 | doi=10.1086/300413 | bibcode=1998AJ....116..284E | s2cid=122285420 | doi-access=free }}</ref>
<ref name=zorec2012>{{cite journal |last1=Zorec |first1=J. |last2=Royer |first2=F. |title=Rotational velocities of A-type stars. IV. Evolution of rotational velocities |journal=Astronomy and Astrophysics |date=2012 |volume=537 |pages=A120 |doi=10.1051/0004-6361/201117691 |arxiv=1201.2052 |bibcode=2012A&A...537A.120Z }}</ref>
</references> {{Stars of Ursa Major}}
Ursae Majoris, Lambda Category:Ursa Major Category:A-type subgiants Tania Borealis Ursae Majoris, 33 050372 4033 089021 Category:Durchmusterung objects Category:Population I stars