Yildun, a white main-sequence star in Ursa Minor
Yildun is a white main-sequence star in the constellation Ursa Minor. At 172 light years away, it shines at an apparent visual magnitude of 4.35.
Yildun (HIP 85822)
Yildun is a white main-sequence star in the constellation Ursa Minor. At 172 light years away, it shines at an apparent visual magnitude of 4.35. It is moving through the Galaxy at a speed of 15.8 km/s relative to the Sun. Its projected Galactic orbit carries it between 24,100 and 27,100 light years from the center of the Galaxy.
Sky position: RA 17h 32.2m, Dec +86° 35.4'
Common designations: Yildun, Delta Ursae Minoris, 23 Ursae Minoris, HIP 85822, HD 166205, HR 6789
Brightest stars in Ursa Minor:
(list all)
| Rank | Mag. | Star |
| 1 | 1.97 | Polaris |
| 2 | 2.07 | Kochab |
| 3 | 3.00 | Pherkad |
| 4 | 4.21 | Epsilon Ursae Minoris |
| 5 | 4.25 | 5 Ursae Minoris |
| 6 | 4.29 | Zeta Ursae Minoris |
7
| 4.35
) Yildun
| Rank | Mag. | Star |
| 8 | 4.63 | RR Ursae Minoris |
| 9 | 4.80 | 4 Ursae Minoris |
| 10 | 4.95 | Eta Ursae Minoris |
| 11 | 5.00 | Theta Ursae Minoris |
| 12 | 5.02 | Pherkad Minor |
| 13 | 5.15 | Gliese 580.2 |
| 14 | 5.18 | HR 5334 |
| 15 | 5.48 | 19 Ursae Minoris |
| 16 | 5.50 | HR 5139 |
| 17 | 5.55 | HR 6173 |
Hover over other bright stars to identify or click to jump.
Galactic Orbit of Yildun
(compared to the Sun)
E
ccentricity: 5.8% vs. 16.0%Angle φ : 18.2°vs. 26.0°
Semi-major axis : 7,859 pc vs. 8,686 pc
Semi-minor axis: 7,846 pc vs. 8,574 pc
Focus-to-center
: 457 pcvs. 1,388 pcSemilatus rectum : 7,833 pc vs. 8,464 pc
Perigalacticon: 7,403 pc vs. 7,297 pc
Apogalacticon
: 8,316 pcvs. 10,074 pcSome Tabulated XHIP Data for Yildun
(see also: SIMBAD)
Astrometry
2007A&A...474..653V
| Position | Proper Motion | |
| Right Ascension: | 263.05373781° ±0.12 mas | 9.50 ±0.20 mas/yr. |
| Declination: | 86.58632948° ±0.14 mas | 54.60 ±0.20 mas/yr. |
| Galactic Longitude: | 119.28602124° | 48.94 mas/yr. |
| Galactic Latitude: | 28.23771325° | -26.00 mas/yr. |
Parallax: 18.95 ± 0.14 mas
Spectrography
Spectral Type: A0V 1995ApJS...99..135A.
Radial Velocity: -7.60 ±2.70 km/s [A rating] 2006AstL...32..759G.
Iron Abundance [Fe/H]:
n/a
Photometry
band
magnitude
Abs. Mag.
U
B
4.37
0.76
V
4.35
0.74
R
I
4.31
0.70
J
4.05
0.44
H
4.33
0.72
K
4.26
0.65
B-V: +0.02 V-I: +0.04
Derivations
Heliocentric distance: 52.77 pc (0.7% margin of error)
Galactocentric distance: 7,423 pc
Transverse velocity: 13.9 km/s
3D heliocentric position and motion:
|
toward: |
Galactic center | Galactic rotation | North Galactic Pole |
| Position ( X, Y, Z) | -22.7 pc | 40.5 pc | 25.0 pc |
| Velocity (U, V, W) | -8.9 km/s | -9.1 km/s | -9.3 km/s |