Pi1 Ursae Minoris

π1 Ursae Minoris
Observation data
Epoch 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)−16.27±0.09[5] km/s
Proper motion (μ) RA: −224.25[1] mas/yr
Dec.: +108.19[1] mas/yr
Parallax (π)45.77 ± 0.37[1] mas
Distance71.3 ± 0.6 ly
(21.8 ± 0.2 pc)
Absolute magnitude (MV)4.94±0.04[6]
π1 UMi B
Radial velocity (Rv)−15.40±0.70[5] km/s
Proper motion (μ) RA: −216.84[1] mas/yr
Dec.: −106.31[1] mas/yr
Parallax (π)46.48 ± 0.49[1] mas
Distance70.2 ± 0.7 ly
(21.5 ± 0.2 pc)
Details
π1 UMi A
Mass1.02[7] M☉
Surface gravity (log g)4.40[8] cgs
Temperature5,490[9] K
Metallicity [Fe/H]−0.22[10] dex
Age9.22±3.84[9] Gyr
π1 UMi B
Mass0.92[7] M☉
Surface gravity (log g)4.50[8] cgs
Temperature5,408[8] K
Metallicity [Fe/H]−0.18[10] dex
Other designations
π1 UMi, ADS 9696, WDS J15292+8027[11]
π1 UMi A: BD+80° 480, HD 139777, HIP 75809, HR 5829, SAO 2556
π1 UMi B: BD+80° 481, HD 139813, HIP 75829, SAO 2558
Database references
SIMBADπ1 UMi AB
π1 UMi A
π1 UMi B

Pi1 Ursae Minoris[12] is a common proper motion binary star[13] system in the northern circumpolar constellation of Ursa Minor. The pair have apparent visual magnitudes of +6.58 and +7.31,[2] placing them below the brightness limit of stars that can be readily viewed with the naked eye. They are located about 70 light years from the Sun. The two have an angular separation of 31.4 arc seconds,[13] which corresponds to a physical separation of about 680 AU,[14] and orbit each other with a period of about 13,100 years.[7] Both are solar analogs and are candidate members of the Hercules-Lyra association, one of the nearest moving groups to the Sun.[14]

References

  1. 1 2 3 4 5 6 7 8 9 10 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.
  2. 1 2 3 4 5 6 7 Johnson, Harold L. (May 1953), "Photoelectric Observations of Visual Double Stars.", Astrophysical Journal, 117: 361, Bibcode:1953ApJ...117..361J, doi:10.1086/145700.
  3. ↑ 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.
  4. ↑ Abt, H. A. (1981), "Visual multiples. VII - MK classifications", The Astrophysical Journal Supplement Series, 45: 437, Bibcode:1981ApJS...45..437A, doi:10.1086/190719.
  5. 1 2 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, A61.
  6. ↑ 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.
  7. 1 2 3 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, 87.
  8. 1 2 3 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, A128.
  9. 1 2 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, L8.
  10. 1 2 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.
  11. ↑ "** STF 1972AB". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-06-26.
  12. ↑ Kepple, George Robert; Sanner, Glen W. (1998), The Night Sky Observers Guide: Spring & summer, 2, Willmann-Bell, p. 418, ISBN 0943396603.
  13. 1 2 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.
  14. 1 2 Eisenbeiss, T.; et al. (August 2013), "The Hercules-Lyra association revisited. New age estimation and multiplicity study", Astronomy & Astrophysics, 556: 19, arXiv:1312.4045, Bibcode:2013A&A...556A..53E, doi:10.1051/0004-6361/201118362, A53.
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