RR Ursae Minoris
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Ursa Minor |
Right ascension | 14h 57m 35.01625s[1] |
Declination | +65° 55′ 56.9143″[1] |
Apparent magnitude (V) | 4.44 - 4.85[2] |
Characteristics | |
Spectral type | M4.55 III[3] |
B−V color index | 1.590±0.017[4] |
Variable type | SRb[5] |
Astrometry | |
Radial velocity (Rv) | 6.21±0.30[6] km/s |
Proper motion (μ) | RA: −82.191[1] mas/yr Dec.: +26.981[1] mas/yr |
Parallax (π) | 10.0206 ± 0.6341 mas[1] |
Distance | 330 ± 20 ly (100 ± 6 pc) |
Absolute magnitude (MV) | −1.11[4] |
Orbit[7] | |
Period (P) | 748.9 d |
Eccentricity (e) | 0.13±0.05 |
Inclination (i) | 79.6±2.4[8]° |
Longitude of the node (Ω) | 48.0±2.5[8]° |
Periastron epoch (T) | 2,444,419±46 JD |
Argument of periastron (ω) (secondary) | 212±22° |
Semi-amplitude (K1) (primary) | 8.3±0.3 km/s |
Details | |
Mass | 1.15±0.1[9] M☉ |
Radius | 103[10] R☉ |
Luminosity | 931.23[4] L☉ |
Surface gravity (log g) | 0.00[11] cgs |
Temperature | 3,464[12] K |
Other designations | |
Database references | |
SIMBAD | data |
RR Ursae Minoris, or RR UMi, is a binary star[11] system in the northern circumpolar constellation of Ursa Minor. It can be viewed with the naked eye, typically having an apparent visual magnitude of around 4.710.[8] Based upon an annual parallax shift of 10.0 mas[1] as seen from Earth's orbit, it is located 330 light years away. The system is moving further from the Sun with a heliocentric radial velocity of +6 km/s.[6]
This is a single-lined spectroscopic binary system with an orbital period of 2.05 years and an eccentricity of 0.13. The a sin i value is 8.4×107 km (0.56 AU),[7] where a is the semimajor axis and i is the orbital inclination to the line of sight from the Earth. The system is a source for X-ray and far-UV emission, with the latter most likely coming from the companion.[11]
The primary component is an aging red giant star on the asymptotic giant branch[11] with a stellar classification of M4.5 III.[3] It is a semiregular variable of subtype SRb,[5] ranging from magnitude 4.44 to 4.85 over a period of 43.3 days.[2] The interferometry-measured angular diameter of the primary component is 9.6±0.7 mas,[14] which, at its estimated distance, equates to a physical radius of about 103 times the radius of the Sun.[10]
References
- ^ a b c d e f 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 Otero, Sebastian Alberto (16 November 2009). "RR Ursae Minoris". AAVSO Website. American Association of Variable Star Observers. Retrieved 18 May 2014.
- ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
- ^ a b c Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015.
- ^ a b Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085.
- ^ 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. A61.
- ^ a b Batten, A. H.; Fletcher, J. M. (July 1986). "A revised spectroscopic orbit for RR Ursae Minoris". Publications of the Astronomical Society of the Pacific. 98: 647–650. Bibcode:1986PASP...98..647B. doi:10.1086/131808.
- ^ a b c Ren, Shulin; Fu, Yanning (March 2013). "Hipparcos Photocentric Orbits of 72 Single-lined Spectroscopic Binaries". The Astronomical Journal. 145 (3): 7. Bibcode:2013AJ....145...81R. doi:10.1088/0004-6256/145/3/81. 81.
- ^ Halabi, Ghina M.; Eid, Mounib El (2015). "Exploring masses and CNO surface abundances of red giant stars". Monthly Notices of the Royal Astronomical Society. 451 (3): 2957. arXiv:1507.01517. Bibcode:2015MNRAS.451.2957H. doi:10.1093/mnras/stv1141.
- ^ a b Lang, Kenneth R. (2006). Astrophysical formulae. Astronomy and astrophysics library. Vol. 1 (3rd ed.). Birkhäuser. ISBN 3-540-29692-1. The radius (R*) is given by:
- ^ a b c d Ortiz, Roberto; Guerrero, Martín A. (2016). "Ultraviolet emission from main-sequence companions of AGB stars". Monthly Notices of the Royal Astronomical Society. 461 (3): 3036. arXiv:1606.09086. Bibcode:2016MNRAS.461.3036O. doi:10.1093/mnras/stw1547.
- ^ Soubiran, Caroline; et al. (2016). "The PASTEL catalogue: 2016 version". Astronomy & Astrophysics. 591: A118. arXiv:1605.07384. Bibcode:2016A&A...591A.118S. doi:10.1051/0004-6361/201628497.
- ^ "RR UMi". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved September 7, 2018.
- ^ Richichi, A.; et al. (February 2005). "CHARM2: An updated Catalog of High Angular Resolution Measurements". Astronomy and Astrophysics. 431 (2): 773–777. Bibcode:2005A&A...431..773R. doi:10.1051/0004-6361:20042039.