Delta Ursae Minoris
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ursa Minor[1] |
| Right ascension | 17h 32m 12.9s[2] |
| Declination | 86° 35′ 11.25″[2] |
| Apparent magnitude (V) | 4.35[2] |
| Characteristics | |
| Spectral type | A1Vn[2] |
| Astrometry | |
| Radial velocity (Rv) | −7.6[2] km/s |
| Parallax (π) | 18.95 ± 0.14 mas[2] |
| Distance | 172 ± 1 ly (52.8 ± 0.4 pc) |
| Absolute magnitude (MV) | 0.62[3] |
| Details | |
| Radius | 2.8[1] R☉ |
| Luminosity | 47[1] L☉ |
| Temperature | 9000[1] K |
| Rotation | 19 hours[1] |
| Other designations | |
Delta Ursae Minoris (δ UMi, δ Ursae Minoris; also 23 UMi) is a star in the constellation Ursa Minor. It has the traditional name Yildun (also spelled Vildiur, Jildun, Gildun, and Yilduz), from the Turkish yıldız "star". It may also[citation needed] have been called Pherkard, an alternate spelling of Pherkad, used for γ UMi and 11 UMi.
Delta Ursae Minoris is a white A-type main sequence dwarf with an apparent magnitude of +4.35.[2] It is approximately 183 light years from Earth.
In science fiction
The star is mentioned in the Honorverse, a series of military science fiction novels written by David Weber, as the headquarters of Technodyne Industries of Yildun, a major Solarian League shipbuilding corporation with rather questionable ethics (e.g. business ties with Manpower Incorporated and Jessyk Combine, both of Mesa), though the star system is described as including only a (highly mineral-and-metals-rich) asteroid belt.
References
- ^ a b c d e Jim Kaler. "YILDUN (Delta Ursae Minoris)". Stars.astro.illinois.edu. Retrieved 2012-03-05.
- ^ a b c d e f g "Delta Ursae Minoris". SIMBAD Astronomical Database. Retrieved 2012-03-04.
- ^ Jim Kaler. "The Polar Project". University of Illinois. Retrieved 2012-03-04.
External links
- Delta Ursae Minoris on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
- YILDUN (Delta Ursae Minoris) – Jim Kaler
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