Common proper motion binary star in the constellation Ursa Minor
π1 Ursae Minoris
Observation dataEpoch J2000.0 Equinox J2000.0 (ICRS )
Constellation Ursa Minor
π1 UMi A
Right ascension 15h 29m 11.18599s [ 1]
Declination +80° 26′ 54.9713″[ 1]
Apparent magnitude (V)+6.58[ 2]
π1 UMi B
Right ascension 15h 29m 23.59426s [ 1]
Declination +80° 27′ 00.9675″[ 1]
Apparent magnitude (V)+7.31[ 2]
Characteristics
π1 UMi A
Spectral type
G1.5 V(n)[ 3]
U−B color index
+0.13[ 2]
B−V color index
+0.67[ 2]
π1 UMi B
Spectral type
G9 V[ 4]
U−B color index
+0.37[ 2]
B−V color index
+0.79[ 2]
Astrometry π1 UMi A Radial velocity (Rv )± 0.09[ 5] km/s Proper motion (μ) RA: −225.109[ 6] mas /yr Dec.: +107.575[ 6] mas /yr Parallax (π)45.8577± 0.0328 mas [ 6] Distance 71.12 ± 0.05 ly pc ) Absolute magnitude (MV )± 0.04[ 7] π1 UMi B Radial velocity (Rv )± 0.70[ 5] km/s Proper motion (μ) RA: −217.817[ 8] mas /yr Dec.: +105.947[ 8] mas /yr Parallax (π)45.8038± 0.0352 mas [ 8] Distance 71.21 ± 0.05 ly pc ) Details π1 UMi A Mass 1.02[ 9] M ☉ Radius 0.98[ 6] R ☉ Luminosity 0.929[ 6] L ☉ Surface gravity (log g )4.40[ 10] cgs Temperature 5,771[ 10] K Metallicity [Fe/H] −0.22[ 11] dex Age ± 3.84[ 12] Gyr π1 UMi B Mass 0.92[ 9] M ☉ Radius 0.84[ 8] R ☉ Luminosity 0.520[ 8] L ☉ Surface gravity (log g )4.50[ 10] cgs Temperature 5,408[ 10] K Metallicity [Fe/H] −0.18[ 11] dex Other designations π1 UMi , ADS 9696WDS J15292+8027[ 13] π1 UMi A : BD +80°480HD 139777HIP 75809HR 5829SAO 2556π1 UMi B : BD +80°481HD 139813HIP 75829SAO 2558Database references SIMBAD π1 UMi AB π1 UMi A π1 UMi B
Pi1 Ursae Minoris [ 14] common proper motion binary star [ 15] circumpolar constellation of Ursa Minor . The pair have apparent visual magnitudes of +6.58 and +7.31, with a combined magnitude of 6.1.[ 2] light years from the Sun . The two have an angular separation of 31.4 arc seconds ,[ 15] AU ,[ 16] period of about 13,100 years.[ 9]
Both stars are solar analogs and have been listed as possible members of the Hercules-Lyra association , one of the nearest moving groups to the Sun ,[ 16] [ 17] 1 Ursae Minoris A, has a mass 2% higher than the sun, an almost identical effective temperature at K the sun's , and a bolometric luminosity 93% of the sun's . The secondary, π1 Ursae Minoris B, has a mass 92% of the sun's, a slightly lower temperature of
References
^ a b c d van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics , 474 (2): 653– 664, arXiv :0708.1752 Bibcode :2007A&A...474..653V , doi :10.1051/0004-6361:20078357 , S2CID 18759600 . ^ a b c d e f g Johnson, Harold L. (May 1953), "Photoelectric Observations of Visual Double Stars.", Astrophysical Journal , 117 : 361, Bibcode :1953ApJ...117..361J , doi :10.1086/145700 . ^ Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal 132 (1): 161– 170, arXiv :astro-ph/0603770 Bibcode :2006AJ....132..161G , doi :10.1086/504637 , S2CID 119476992 . ^ Abt, H. A. (1981), "Visual multiples. VII - MK classifications", The Astrophysical Journal Supplement Series , 45 : 437, Bibcode :1981ApJS...45..437A , doi :10.1086/190719 . ^ a b de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics , 546 : 14, arXiv :1208.3048 Bibcode :2012A&A...546A..61D , doi :10.1051/0004-6361/201219219 , S2CID 59451347 , A61. ^ a b c d e Brown, A. G. A. ; et al. (Gaia collaboration ) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties" . Astronomy & Astrophysics 616 . A1. arXiv :1804.09365 Bibcode :2018A&A...616A...1G doi :10.1051/0004-6361/201833051 Gaia DR2 record for this source at VizieR .^ Porto de Mello, G. F.; et al. (March 2014), "A photometric and spectroscopic survey of solar twin stars within 50 parsecs of the Sun; I. Atmospheric parameters and color similarity to the Sun", Astronomy and Astrophysics , 563 : A52, arXiv :1312.7571 Bibcode :2014A&A...563A..52P , doi :10.1051/0004-6361/201322277 , S2CID 119111150 . ^ a b c d e Brown, A. G. A. ; et al. (Gaia collaboration ) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties" . Astronomy & Astrophysics 616 . A1. arXiv :1804.09365 Bibcode :2018A&A...616A...1G doi :10.1051/0004-6361/201833051 Gaia DR2 record for this source at VizieR .^ a b c Tokovinin, Andrei (2014), "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs", The Astronomical Journal , 147 (4): 14, arXiv :1401.6827 Bibcode :2014AJ....147...87T , doi :10.1088/0004-6256/147/4/87 , S2CID 56066740 , 87. ^ a b c d Mishenina, T. V.; et al. (April 2013), "Abundances of neutron-capture elements in stars of the Galactic disk substructures", Astronomy & Astrophysics , 552 : 12, arXiv :1303.1730 Bibcode :2013A&A...552A.128M , doi :10.1051/0004-6361/201220687 , S2CID 119268097 , A128. ^ a b Casagrande, L.; et al. (2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", Astronomy & Astrophysics , 530 (A138): 21, arXiv :1103.4651 Bibcode :2011A&A...530A.138C , doi :10.1051/0004-6361/201016276 , S2CID 56118016 . ^ Pace, G. (March 2013), "Chromospheric activity as age indicator. An L-shaped chromospheric-activity versus age diagram", Astronomy & Astrophysics , 551 : 4, arXiv :1301.5651 Bibcode :2013A&A...551L...8P , doi :10.1051/0004-6361/201220364 , S2CID 56420519 , L8. ^ "** STF 1972AB" . SIMBAD Centre de données astronomiques de Strasbourg . Retrieved 2017-06-26 .{{cite web }}: CS1 maint: postscript (link )^ Kepple, George Robert; Sanner, Glen W. (1998), The Night Sky Observers Guide: Spring & summer ISBN 0943396603 ^ a b Lépine, Sébastien; Bongiorno, Bethany (March 2007), "New Distant Companions to Known Nearby Stars. II. Faint Companions of Hipparcos Stars and the Frequency of Wide Binary Systems", The Astronomical Journal , 133 (3): 889– 905, arXiv :astro-ph/0610605 Bibcode :2007AJ....133..889L , doi :10.1086/510333 , S2CID 16800796 . ^ a b Eisenbeiss, T.; et al. (August 2013), "The Hercules-Lyra association revisited. New age estimation and multiplicity study" (PDF) , Astronomy & Astrophysics , 556 : 19, arXiv :1312.4045 Bibcode :2013A&A...556A..53E , doi :10.1051/0004-6361/201118362 , S2CID 119275785 , A53. [permanent dead link ^ Lopez-Santiago, J.; Montes, D.; Crespo-Chacon, I.; Fernandez-Figueroa, M. J. (2006), "The Nearest Young Moving Groups", The Astrophysical Journal , 643 (2): 1160– 1165, arXiv :astro-ph/0601573 Bibcode :2006ApJ...643.1160L , doi :10.1086/503183 , S2CID 119520529 .
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