Astronomy:Pi1 Ursae Minoris
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Short description: Common proper motion binary star in the constellation Ursa Minor
| Observation data {{#ifeq:J2000.0|J2000.0 (ICRS)|Epoch J2000.0 Equinox J2000.0 (ICRS)| [[History:Epoch|Epoch J2000.0]] [[Astronomy:Equinox (celestial coordinates)|Equinox J2000.0}} | |
|---|---|
| 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: −225.109[6] mas/yr Dec.: +107.575[6] mas/yr |
| Parallax (π) | 45.8577 ± 0.0328[6] mas |
| Distance | 71.12 ± 0.05 ly (21.81 ± 0.02 pc) |
| Absolute magnitude (MV) | 4.94±0.04[7] |
| π1 UMi B | |
| Radial velocity (Rv) | −15.40±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[8] mas |
| Distance | 71.21 ± 0.05 ly (21.83 ± 0.02 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 | 9.22±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 A: {{{names1}}} | |
| π1 UMi B: {{{names2}}} | |
| Database references | |
| SIMBAD | π1 UMi AB |
| π1 UMi A | |
| π1 UMi B | |
Pi1 Ursae Minoris[14] is a common proper motion binary star[15] system in the northern 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] They are located about 71 light years from the Sun. The two have an angular separation of 31.4 arc seconds,[15] which corresponds to a physical separation of about 680 AU,[16] and orbit each other with a 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] although this is now considered unlikely.[17] The primary, π1 Ursae Minoris A, has a mass 2% higher than the sun, an almost identical effective temperature at 5,771 K, a radius 98% of 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 5,408 K, a radius 84% of the sun's, and a luminosity slightly over half of the sun.
References
- ↑ 1.0 1.1 1.2 1.3 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Johnson, Harold L. (May 1953), "Photoelectric Observations of Visual Double Stars.", Astrophysical Journal 117: 361, doi:10.1086/145700, Bibcode: 1953ApJ...117..361J.
- ↑ 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, doi:10.1086/504637, Bibcode: 2006AJ....132..161G.
- ↑ Abt, H. A. (1981), "Visual multiples. VII - MK classifications", The Astrophysical Journal Supplement Series 45: 437, doi:10.1086/190719, Bibcode: 1981ApJS...45..437A.
- ↑ 5.0 5.1 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, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D.
- ↑ 6.0 6.1 6.2 6.3 6.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. 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, doi:10.1051/0004-6361/201322277, Bibcode: 2014A&A...563A..52P.
- ↑ 8.0 8.1 8.2 8.3 8.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 9.0 9.1 9.2 Tokovinin, Andrei (2014), "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs", The Astronomical Journal 147 (4): 14, doi:10.1088/0004-6256/147/4/87, 87, Bibcode: 2014AJ....147...87T.
- ↑ 10.0 10.1 10.2 10.3 Mishenina, T. V. et al. (April 2013), "Abundances of neutron-capture elements in stars of the Galactic disk substructures", Astronomy & Astrophysics 552: 12, doi:10.1051/0004-6361/201220687, A128, Bibcode: 2013A&A...552A.128M.
- ↑ 11.0 11.1 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, doi:10.1051/0004-6361/201016276, Bibcode: 2011A&A...530A.138C.
- ↑ Pace, G. (March 2013), "Chromospheric activity as age indicator. An L-shaped chromospheric-activity versus age diagram", Astronomy & Astrophysics 551: 4, doi:10.1051/0004-6361/201220364, L8, Bibcode: 2013A&A...551L...8P.
- ↑ "** STF 1972AB". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A%2A+STF+1972AB.
- ↑ Kepple, George Robert; Sanner, Glen W. (1998), The Night Sky Observers Guide: Spring & summer, 2, Willmann-Bell, p. 418, ISBN 0943396603, https://books.google.com/books?id=Yc0PAQAAMAAJ.
- ↑ 15.0 15.1 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, doi:10.1086/510333, Bibcode: 2007AJ....133..889L.
- ↑ 16.0 16.1 Eisenbeiss, T. et al. (August 2013), "The Hercules-Lyra association revisited. New age estimation and multiplicity study", Astronomy & Astrophysics 556: 19, doi:10.1051/0004-6361/201118362, A53, Bibcode: 2013A&A...556A..53E, http://goedoc.uni-goettingen.de/goescholar/bitstream/handle/1/10866/aa18362-11.pdf?sequence=1.[yes|permanent dead link|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, doi:10.1086/503183, Bibcode: 2006ApJ...643.1160L.
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