Pi2 Ursae Minoris

{{Short description|Binary star system in the constellation Ursa Minor}}

{{other stars by Bayer designation|Pi Ursae Minoris{{!}}π Ursae Minoris}}

{{Starbox begin

| name = Pi² Ursae Minoris

}}

{{Starbox observe

| epoch = J2000

| constell = Ursa Minor

| ra = {{RA|15|39|38.61131}}

| dec = {{DEC|+79|58|59.5495}}

| appmag_v = 6.89 {{nowrap|(7.32 + 8.15)}}

}}

{{Starbox character

| type =

| class = F1V + G0

| b-v = {{val|0.392|0.015}}

| u-b =

| variable =

}}

{{Starbox astrometry

| radial_v = {{val|−32.10|1.8}}

| prop_mo_ra = −32.643

| prop_mo_dec = 41.425

| parallax = 8.1090

| p_error = 0.2844

| parallax_footnote =

| absmag_v = {{Val|1.69|0.08}}

}}

{{Starbox orbit

| reference =

| period = {{val|171.62|8.68}}

| axis = {{val|0.464|0.083}}

| inclination = {{val|135.2|10.5}}

| node = {{val|123.4|32.6}}

| periastron = {{val|1904.15|2.89}}

| eccentricity = {{val|0.961|0.014}}

| periarg = {{val|274.0|22.4}}

}}

{{Starbox detail

| component1 =

| mass = 1.87

| radius = {{val|3.82|0.59|1.27}}

| luminosity = {{val|16.5|0.7}}

| temperature = {{val|6858|80|fmt=commas}}

| gravity =

| metal_fe = +0.09

| age_gyr = 1.20

| rotational_velocity =

}}

{{Starbox catalog

| names = {{odlist | B=π² UMi | F=18 Ursae Minoris | BD=+80°487 | HD=141652 | HIP=76695 | SAO=2588 | WDS=J15396+7959AB }}

}}

{{Starbox reference

| Simbad = pi.02+UMi

}}

Pi² Ursae Minoris, which is Latinized from π² UMi / π² Ursae Minoris, is a binary star system in the northern circumpolar constellation of Ursa Minor. The pair have a combined apparent visual magnitude of 6.89, which can be viewed with a pair of binoculars. They are located at a distance of approximately 400 light years from the Sun based on parallax, but are drifting closer with a radial velocity of −32 km/s.

This star was found to be a double system by O. Struve in 1832, and the pair have now completed a full orbit. There is a lot of scatter in the data though, so the grade of the orbital elements is rated as poor. The system has a high eccentricity of 0.96 and they orbit each other with a period of roughly 172 years. The magnitude 7.32 primary is an F-type main-sequence star with a stellar classification of F1V. The fainter secondary has a magnitude of 8.15 and is G-type star.

At present the angular separation between both stars is 0.67 arcseconds [https://www.stelledoppie.it/index2.php?iddoppia=63485].

References

{{reflist|refs=

{{Cite web

| title=The astronomical magnitude scale

| website=International Comet Quarterly

| url=http://www.icq.eps.harvard.edu/MagScale.html

| access-date=2020-12-17 }}

{{citation

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| last3=Asplund | first3=M. | last4=Cassisi | first4=S.

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| display-authors=1 | journal=Astronomy and Astrophysics

| volume=530 | page=A138 | date=June 2011

| doi=10.1051/0004-6361/201016276 | s2cid=56118016

| bibcode=2011A&A...530A.138C | arxiv=1103.4651 }}

{{cite journal

| title=Dynamical Masses of a Selected Sample of Orbital Binaries

| last1=Malkov | first1=O. Yu. | last2=Tamazian | first2=V. S.

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| display-authors=1 | journal=Astronomy & Astrophysics

| volume=546 | id=A69 | pages=5 | date=2012

| doi=10.1051/0004-6361/201219774 | doi-access=free

| bibcode=2012A&A...546A..69M }}

{{cite journal

| title=The Geneva-Copenhagen survey of the Solar neighbourhood. II. New uvby calibrations and rediscussion of stellar ages, the G dwarf problem, age-metallicity diagram, and heating mechanisms of the disk

| display-authors=1 | last1=Holmberg | first1=J.

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| journal=Astronomy & Astrophysics

| volume=475 | issue=2 | pages=519–537 | date=2007

| arxiv=0707.1891 | bibcode=2007A&A...475..519H

| doi=10.1051/0004-6361:20077221 | s2cid=119054949 }}

{{cite journal

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| last1=Anderson | first1=E. | last2=Francis | first2=Ch.

| journal=Astronomy Letters

| volume=38 | issue=5 | pages=331 | year=2012

| bibcode=2012AstL...38..331A | arxiv=1108.4971

| doi=10.1134/S1063773712050015 | s2cid=119257644 }}

{{cite journal

| title=Spectral classifications in the near infrared of stars with composite spectra. III. Study of a sample of 137 objects with the Aurelie spectrograph

| display-authors=1 | last1=Ginestet | first1=N.

| last2=Carquillat | first2=J. M. | last3=Jaschek | first3=C.

| journal=Astronomy and Astrophysics Supplement

| volume=134 | issue=3 | pages=473 | year=1999

| bibcode=1999A&AS..134..473G

| doi=10.1051/aas:1999444 | doi-access=free }}

{{cite journal

| title=Speckle Interferometry at the Usno Flagstaff Station: Observations Obtained in 2003-2004 and 17 New Orbits

| display-authors=1 | last1=Hartkopf | first1=William I.

| last2=Mason | first2=Brian D. | last3=Rafferty | first3=Theodore J.

| journal=The Astronomical Journal

| volume=135 | issue=4 | pages=1334 | year=2008