Delta Ursae Minoris
Sign in to saveAlso known as Yildun, δ UMi, δ Ursae Minoris, HR 6789, 23 UMi, 23 Ursae Minoris, HIP 85822, HIC 85822
Delta Ursae Minoris, Latinized from δ Ursae Minoris, formally named Yildun , is a white-hued star in the northern circumpolar constellation of Ursa Minor, forming the second star in the bear's tail. It is visible to the naked eye with an apparent visual magnitude of 4.36. Based upon an annual parallax shift of 18.95 mas as seen from Earth, 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.
Astronomical data · SIMBAD
- Object type
- PM*
- Spectral type
- A1Van
- Distance
- 182 light-years
- Redshift
- z = -0.000029753474657057133
- Coordinates
- RA 263.0542° · Dec 86.5865°
via SIMBAD · CDS Strasbourg
Wikidata facts
- Part of
- Curved Array
- Constellation
- Ursa Minor
- Distance from Earth
- 55.9278
- Radius
- 2.8
- Variable-star type
- Cepheid variable
Show 14 more facts
- catalog code
- WDS J17322+8635A
- spectral class
- A0
- apparent magnitude
- 4.321091
- effective temperature
- 9070
- parallax
- 17.8802
- absolute magnitude
- 0.62
- radial velocity
- -8.92
- stellar rotational velocity
- 180
- epoch
- J2000.0
- right ascension component of proper motion
- 10.025
- declination component of proper motion
- 54.053
- age estimated by a dating method
- 327
- right ascension
- 263.0541592214034
- declination
- 86.58645960557529
Sources (3)
via Wikidata · CC0
~2 min read
Encyclopedic overview
4 sectionsContents
- Description
- Nomenclature
- References
- External links
Delta Ursae Minoris, Latinized from δ Ursae Minoris, formally named Yildun , is a white-hued star in the northern circumpolar constellation of Ursa Minor, forming the second star in the bear's tail. It is visible to the naked eye with an apparent visual magnitude of 4.36. Based upon an annual parallax shift of 18.95 mas as seen from Earth, 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.
==Description== This is an A-type main-sequence star with a stellar classification of A1 Van, where the 'n' indicates "nebulous" absorption lines in the spectrum due to rapid rotation. It is spinning with a projected rotational velocity of 180 km/s, which is giving the star an oblate shape with an equatorial bulge that is an estimated 7% larger than the polar radius. The star is about 327 million years old with 2.35 times the mass of the Sun. It is radiating about 48 times the Sun's luminosity from its photosphere at an effective temperature of 9,911 K.
Excerpted from Wikipedia’s “Delta Ursae Minoris” article, available under the CC BY-SA 4.0 licence.