G 99-47
Coordinates: 
05h 56m 25.47s, +05° 21′ 48.6″
| Observation data Epoch J2000[1] Equinox J2000[1] |
|
|---|---|
| Constellation | Orion |
| Right ascension | 05h 56m 25.47s[1] |
| Declination | +05° 21′ 48.6″[1] |
| Apparent magnitude (V) | 14.105[2] |
| Characteristics | |
| Spectral type | DAP8.9[3] |
| Apparent magnitude (B) | 14.69[1] |
| Apparent magnitude (V) | 14.10[1] |
| Apparent magnitude (R) | 14.0[1] |
| Apparent magnitude (I) | 13.6[1] |
| Apparent magnitude (J) | 12.930 ± 0.022[1] |
| Apparent magnitude (H) | 12.720 ± 0.025[1] |
| Apparent magnitude (K) | 12.653 ± 0.024[1] |
| Astrometry | |
| Proper motion (μ) | RA: -434[3] mas/yr Dec.: -931[3] mas/yr |
| Parallax (π) | 125.0 ± 3.6[4] mas |
| Distance | 26.1 ± 0.8 ly (8.0 ± 0.2 pc) |
| Absolute magnitude (MV) | 14.59[2][4][note 1] |
| Details | |
| Mass | 0.71 ± 0.03[2] M☉ |
| Radius | 0.011[2][note 2] R☉ |
| Surface gravity (log g) | 8.20 ± 0.05[2] cgs |
| Temperature | 5790 ± 110[2] K |
| Age | 3.97[3][note 3] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
G 99-47 (V1201 Orionis) is a nearby degenerate star (white dwarf) of spectral class DAP8 (DAP8.9,[3] or DAP8.7[2]), the single known component of the system, located in the constellation Orion.
Distance
G 99-47 is probably the tenth closest white dwarf (or possibly the 9th–12th: see Gliese 293, Gliese 518 and Gliese 915). Its trigonometric parallax from the Yale Parallax Catalog is 0.1250 ± 0.0036 arcsec,[4] corresponding to a distance 8.00 ± 0.23 pc, or 26.09 ± 0.75 ly.
Parallax data
| Source | Paper | Parallax, mas | Distance, pc | Distance, ly | Ref. |
|---|---|---|---|---|---|
| Nearby Stars, 3rd ed. prelim., 3rd version | Gliese, Jahreiss, 1991 | 125.1 ± 4.1 | 7.99 ± 0.26 | 26.07 ± 0.85 | [5] |
| YPC, 4th edition | van Altena et al., 1995 | 125.0 ± 3.6 | 8.00 ± 0.23 | 26.09 ± 0.75 | [4] |
Physical parameters
G 99-47's mass is 0.71 ± 0.03 Solar masses;[2] its surface gravity is 108.20 ± 0.05 (1.58 · 108) cm·s−2,[2] or approximately 162 000 of Earth's, corresponding to a radius 7711 km, or 121% of Earth's.
Its temperature is 5790 ± 110 K,[2] almost like the Sun's; its cooling age, i. e. age as degenerate star (not including lifetime as main sequence star and as giant star) is 3.97 Gyr.[3] Due almost equal to the Sun's temperature, GJ 1087 should appear almost the same color as the Sun.
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)
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 4.0 4.1 4.2 4.3 4.4 Yale Trigonometric Parallaxes, Fourth Edition (van Altena+ 1995)
- ↑ Nearby Stars, Preliminary 3rd Version (Gliese+ 1991)
