| 词条 | Pi2 Ursae Minoris |
| 释义 |
|epoch=J2000 |constell=Ursa Minor |ra={{RA|15|39|38.60827}}[1] |dec={{DEC|+79|58|59.5799}}[1] |appmag_v=6.95[2] }}{{Starbox character |class=F1V[3] + G0[5] }}{{Starbox astrometry |radial_v=−32.10 ± 1.8[4] |prop_mo_ra=-32.92[1] |prop_mo_dec=40.28[1] |parallax=8.33 |p_error=0.61 |parallax_footnote=[1] |absmag_v=+1.51[5] }}{{Starbox orbit |reference=[6] |period=171.62 ± 8.68 |axis=0.464 ± 0.083 |inclination=135.2 ± 10.5 |node=123.4 ± 32.6 |periastron=1904.15 ± 2.89 |eccentricity=0.961 ± 0.014 |periarg=274.0 ± 22.4 }}{{Starbox detail | mass = | temperature = 6.858[7] | age_gyr = 1.20[8] | metal_fe = +0.09[8] }}{{Starbox catalog |names={{odlist|F=18 Ursae Minoris|BD=+80°487|HD=141652|HIP=76695|SAO=2588}} }}{{Starbox reference |Simbad=pi.02+UMi }}{{Starbox end}}Pi2 Ursae Minoris (π2 UMi) is a binary star system in the northern circumpolar constellation of Ursa Minor. The pair have apparent magnitudes of 7.32 and 8.15,[9] placing them below the brightness limit of stars that can be readily viewed with the naked eye. They are located about 390 light-years (120 parsecs) away from the Sun. The two have an angular separation of 0.464″ on average, and they orbit each other with a period of about 170 years.[6] The primary star is a F-type dwarf star, and the secondary is G-type.[6] References1. ^1 2 3 4 {{cite journal|title=Validation of the new Hipparcos reduction|url=http://www.aanda.org/index.php?option=com_article&access=bibcode&Itemid=129&bibcode=2007A%2526A...474..653VFUL|author=van Leeuwen, F.|display-authors=etal|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}} {{Stars of Ursa Minor|state=collapsed}}{{multi-star-stub}}2. ^{{cite journal|title=The Tycho-2 catalogue of the 2.5 million brightest stars|author=Høg, E.|display-authors=etal|date=2000|journal=Astronomy and Astrophysics|volume=355|pages=L27–L30|bibcode=2000A&A...355L..27H}} 3. ^{{cite journal|bibcode=1999A&AS..134..473G|title=Spectral classifications in the near infrared of stars with composite spectra. III. Study of a sample of 137 objects with the Aurelie spectrograph|journal=Astronomy and Astrophysics Supplement|volume=134|issue=3|pages=473|author1=Ginestet|first1=N|last2=Carquillat|first2=J. M|last3=Jaschek|first3=C|year=1999|doi=10.1051/aas:1999444}} 4. ^{{cite simbad|title=* pi.02 UMi|accessdate=31 July 2017}} 5. ^{{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 | postscript=. }} 6. ^1 2 3 {{cite journal|bibcode=2008AJ....135.1334H|doi=10.1088/0004-6256/135/4/1334|title=Speckle Interferometry at the Usno Flagstaff Station: Observations Obtained in 2003-2004 and 17 New Orbits|journal=The Astronomical Journal|volume=135|issue=4|pages=1334|year=2008|last1=Hartkopf|first1=William I.|last2=Mason|first2=Brian D.|last3=Rafferty|first3=Theodore J.|url=http://www.dtic.mil/get-tr-doc/pdf?AD=ADA480792}} 7. ^{{cite journal|bibcode=2016A&A...591A.118S|title=The PASTEL catalogue: 2016 version|journal=Astronomy and Astrophysics|volume=591|pages=A118|last1=Soubiran|first1=Caroline|last2=Le Campion|first2=Jean-François|last3=Brouillet|first3=Nathalie|last4=Chemin|first4=Laurent|year=2016|arxiv=1605.07384|doi=10.1051/0004-6361/201628497}} 8. ^1 {{cite journal|bibcode=2011A&A...530A.138C|title=New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey|journal=Astronomy and Astrophysics|volume=530|pages=A138|last1=Casagrande|first1=L.|last2=Schönrich|first2=R.|last3=Asplund|first3=M.|last4=Cassisi|first4=S.|last5=Ramírez|first5=I.|last6=Meléndez|first6=J.|last7=Bensby|first7=T.|last8=Feltzing|first8=S.|author8-link= Sofia Feltzing |year=2011|arxiv=1103.4651|doi=10.1051/0004-6361/201016276}} 9. ^{{cite web|url=http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6|title=Sixth Catalog of Orbits of Visual Binary Stars|publisher=United States Naval Observatory|accessdate=31 July 2017}} 9 : Ursa Minor (constellation)|F-type main-sequence stars|G-type main-sequence stars|Binary stars|Bayer objects|Flamsteed objects|Durchmusterung objects|Henry Draper Catalogue objects|Hipparcos objects |
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