Delta Ursae Minoris

δ Ursae Minoris
Location of δ Ursae Minoris (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ursa Minor[1]
Right ascension 17h 32m 12.99671s[2]
Declination 86° 35′ 11.2584″[2]
Apparent magnitude (V) 4.36[3]
Characteristics
Spectral type A1 Van[4]
U−B color index +0.03[3]
B−V color index +0.02[3]
Astrometry
Radial velocity (Rv)−7.6±2.7[5] km/s
Proper motion (μ) RA: +10.17[2] mas/yr
Dec.: +53.97[2] mas/yr
Parallax (π)18.95 ± 0.14 mas[2]
Distance172 ± 1 ly
(52.8 ± 0.4 pc)
Absolute magnitude (MV)0.62[6]
Details
Mass2.35[7] M☉
Radius2.8[1] R☉
Luminosity47.77[8] L☉
Surface gravity (log g)4.04[7] cgs
Temperature9,911±337[7] K
Rotation19 hours[1]
Rotational velocity (v sin i)154[7] km/s
Age327[7] Myr
Other designations
Yildun, Vildiur, Gildun[9], δ UMi, 23 Ursae Minoris, BD+86°269, FK5 913, GC 24236, HD 166205, HIP 85822, HR 6789, SAO 2937[10]
Database references
SIMBADdata

Delta Ursae Minoris, Latinized from δ Ursae Minoris, formally named Yildun /jɪlˈdʌn/,[11] is a white-hued star in the northern circumpolar constellation of Ursa Minor, forming the second star in the bear's tail.[12] It is visible to the naked eye with an apparent visual magnitude of 4.36.[3] Based upon an annual parallax shift of 18.95 mas as seen from Earth,[2] it is located 172 light years from the Sun. The star is moving closer to the Sun with a radial velocity of about −8 km/s.[5]

  1. ^ a b c Cite error: The named reference KALER was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference clpl4_99 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Gray1987 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference polar was invoked but never defined (see the help page).
  7. ^ a b c d e Cite error: The named reference David2015 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference allen was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ "IAU Catalog of Star Names". Retrieved 28 July 2016.
  12. ^ Cite error: The named reference Ridpath1988 was invoked but never defined (see the help page).