Lambda Ursae Minoris

Lambda Ursae Minoris (λ UMi, λ Ursae Minoris) is a star in the constellation Ursa Minor. It is an M-type red giant with an apparent magnitude of +6.38 and is approximately 880 light years from Earth.

λ Ursae Minoris
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ursa Minor
Right ascension  17h 16m 56.4107s[1]
Declination +89° 02′ 15.734″[1]
Apparent magnitude (V) +6.38[2]
Characteristics
Spectral type M3+ IIIa[3]
U−B color index +1.79[4]
B−V color index +1.57[4]
Variable type SRb[5]
Astrometry
Radial velocity (Rv)+0.19[1] km/s
Proper motion (μ) RA: −23.989[1] mas/yr
Dec.: 3.463[1] mas/yr
Parallax (π)3.7084 ± 0.1329[1] mas
Distance880 ± 30 ly
(270 ± 10 pc)
Absolute magnitude (MV)−0.85[6]
Details
Radius64[1] R☉
Luminosity741[1] L☉
Temperature3,772[1] K
Other designations
HR 7394, HD 183030, BD+88°112, FK5 914, HIP 84535, SAO 3020
Database references
SIMBADdata

Lambda Ursae Minoris is an asymptotic giant branch (AGB) star, a star that has exhausted its core hydrogen and helium and is now fusing material in shells outside its core.[7] AGB stars are often unstable and tend to pulsate, and Lambda Ursae Minoris is classified as a semiregular variable star and its brightness varies by about 0.1 magnitudes.[5] Its variability was discovered from Hipparcos astrometry and it was entered into the General Catalogue of Variable Stars in 1999.[8]

References
  1. 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.
  2. Ducati, J. R. (2002). "VizieR On-line Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". VizieR On-line Data Catalog. Bibcode:2002yCat.2237....0D.
  3. Yamashita, Y. (1967). "MK Spectral Types of Bright M-Type Stars". Publications of the Dominion Astrophysical Observatory Victoria. 13: 47. Bibcode:1967PDAO...13...47Y.
  4. Hoffleit, Dorrit; Jaschek, Carlos (1991). The Bright star catalogue. Bibcode:1991bsc..book.....H.
  5. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/GCVS. Bibcode:2009yCat....102025S.
  6. 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.
  7. Eggen, Olin J. (1992). "Asymptotic Giant Branch Stars Near the Sun". The Astronomical Journal. 104: 275. Bibcode:1992AJ....104..275E. doi:10.1086/116239.
  8. Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Frolov, M. S.; Antipin, S. V.; Kireeva, N. N.; Pastukhova, E. N. (1999). "The 74th Special Name-list of Variable Stars". Information Bulletin on Variable Stars. 4659: 1. Bibcode:1999IBVS.4659....1K.
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