2 Ursae Minoris

2 Ursae Minoris
Observation data
Epoch J2000      Equinox J2000
Constellation Cepheus
Right ascension 01h 08m 44.88005s[1]
Declination 86° 15′ 25.5240″[1]
Apparent magnitude (V) 4.244[2]
Characteristics
Spectral type K2 II-III[3]
B−V color index 1.213±0.012[4]
Astrometry
Radial velocity (Rv)+8.36±0.19[5] km/s
Proper motion (μ) RA: 80.65±0.16[1] mas/yr
Dec.: −11.54±0.17[1] mas/yr
Parallax (π)11.64 ± 0.15 mas[1]
Distance280 ± 4 ly
(86 ± 1 pc)
Absolute magnitude (MV)−0.43[4]
Details
Mass2.27±0.41[6] M☉
Radius24.00+1.15
−0.85[5] R☉
Luminosity215.097±6.132[5] L☉
Surface gravity (log g)2.48±0.17[2] cgs
Temperature4,512.5+62.2
−105.0[5] K
Metallicity [Fe/H]0.068±0.010[2] dex
Rotational velocity (v sin i)1.0[7] km/s
Other designations
2 UMi, BD+85°19, FK5 906, HD 5848, HIP 5372, HR 285, SAO 181[8]
Database references
SIMBADdata

2 Ursae Minoris (2 UMi) is a single[9] star a few degrees away from the northern celestial pole. Despite its Flamsteed designation, the star is actually located in the constellation Cepheus. This change occurred when the constellation boundaries were formally set in 1930 by Eugene Delporte. Therefore, the star is usually referred only by its catalog numbers such as HR 285 or HD 5848. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.244.[2] This object is located 280 light years away and is moving further from the Earth with a heliocentric radial velocity of +8 km/s.[5] It is a candidate member of the Hyades Supercluster.[2]

This is an aging K-type star with a stellar classification of K2 II-III,[3] showing a luminosity class with blended traits of a giant and a bright giant. It has 2.3[6] times the mass of the Sun and has expanded to 24[5] times the Sun's radius. The star is radiating around 215[5] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,513 K.[5]

  1. ^ a b c d e Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference Tabernero2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Eggen1962 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  5. ^ a b c d e f g h Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference apjl674_1_L53 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Lèbre2006 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).