Wolf 489
Coordinates: 
13h 36m 31.81s, +03° 40′ 45.9″
| Observation data Epoch J2000[1] Equinox J2000[1] | |
|---|---|
| Constellation | Virgo |
| Right ascension | 13h 36m 31.81s[1] |
| Declination | +03° 40′ 45.″[1] |
| Apparent magnitude (V) | 14.66[2] |
| Characteristics | |
| Spectral type | DZ10.0[2][3] |
| Apparent magnitude (B) | 15.59[1] |
| Apparent magnitude (V) | 14.63[1] |
| Apparent magnitude (R) | 14.0[1] |
| Apparent magnitude (I) | 14.1[1] |
| Apparent magnitude (J) | 13.06[1] |
| Apparent magnitude (H) | 12.82[1] |
| Apparent magnitude (K) | 12.69[1] |
| Astrometry | |
| Proper motion (μ) | RA: -3706[3] mas/yr Dec.: -1149[3] mas/yr |
| Parallax (π) | 121.4 ± 3.4[4] mas |
| Distance | 26.9 ± 0.8 ly (8.2 ± 0.2 pc) |
| Absolute magnitude (MV) | 15.08[2][4][note 1] |
| Details | |
| Mass | 0.55 ± 0.03[2] M☉ |
| Radius | 0.013[2][note 2] R☉ |
| Surface gravity (log g) | 7.95 ± 0.02[2] cgs |
| Temperature | 5030 ± 120[2] K |
| Age | 5.19[3][note 3] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Wolf 489 (WD 1334+039, LHS 46, G 062-053, Gliese 518) is a nearby degenerate star (white dwarf) of spectral class DZ10.0[2][3]), the single known component of the system, located in the constellation Virgo.
Distance
Wolf 489, probably, is the 12th closest white dwarf, or, possibly, 9th–14th (see Gliese 293, GJ 1087, Gliese 915, GJ 1276 and Gliese 318). Its trigonometric parallax from YPC (Yale Parallax Catalog) is 121.4 ± 3.4 mas,[4] corresponding to a distance 8.24 ± 0.23 pc, or 26.87 ± 0.75 ly.
| Source | Paper | Parallax, mas | Distance, pc | Distance, ly | Ref. |
|---|---|---|---|---|---|
| Woolley (1970) | Woolley et al., 1970 | 135 ± 12 | 7.4 ± 0.7 | 24.2 ± 2.1 | [5] |
| GJ, 3rd version | Gliese, Jahreiss, 1991 | 122.2 ± 3.9 | 8.18 ± 0.26 | 26.69 ± 0.85 | [6] |
| YPC, 4th edition | van Altena et al., 1995 | 121.4 ± 3.4 | 8.24 ± 0.23 | 26.87 ± 0.75 | [4] |
Physical parameters
Wolf 489's mass is 0.55 ± 0.03 Solar masses,[2] its surface gravity is 107.95 ± 0.02 (8.91 · 107) cm·s−2,[2] or approximately 91 000 of Earth's, corresponding to a radius 9089 km, or 143% of Earth's.
Wolf 489's temperature is 5030 ± 120 K[2] (comparable with that of early K-type main sequence stars); its cooling age, i. e. age as degenerate star (not including lifetime as main sequence star and as giant star) is 5.19 Gyr.[3] Despite its official classification as "white dwarf", Wolf 489 is not actually white due to low temperature, and should appear the same color as K-type main sequence stars, often referred to as "orange dwarfs".
Notes
- ↑ From apparent magnitude and parallax.
- ↑ From surface gravity and mass.
- ↑ White dwarf cooling age, i. e. age as degenerate star (not including lifetime as main sequence star and as giant star)
See also
References
- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 "GJ 518 -- White Dwarf". Centre de Données astronomiques de Strasbourg. Retrieved 2011-11-02.
- 1 2 3 4 5 6 7 8 9 10 11 12 13 Holberg, J. B.; Sion; Oswalt; McCook; Foran; Subasavage (2008). "A NEW LOOK AT THE LOCAL WHITE DWARF POPULATION". The Astronomical Journal. 135: 1225–1238. Bibcode:2008AJ....135.1225H. doi:10.1088/0004-6256/135/4/1225.
- 1 2 3 4 5 6 7 Sion, Edward M.; Holberg; Oswalt; McCook; Wasatonic (2009). "THE WHITE DWARFS WITHIN 20 PARSECS OF THE SUN: KINEMATICS AND STATISTICS". The Astronomical Journal. 138: 1681–1689. arXiv:0910.1288
. Bibcode:2009AJ....138.1681S. doi:10.1088/0004-6256/138/6/1681. - 1 2 3 4 5 Yale Trigonometric Parallaxes, Fourth Edition (van Altena+ 1995)
- ↑ Stars within 25 pc of the Sun (Woolley+ 1970)
- ↑ Nearby Stars, Preliminary 3rd Version (Gliese+ 1991)