G 99-47
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 56m 25.45999s |
| Declination | +05° 21′ 48.4432″ |
| Apparent magnitude (V) | 14.105 |
| Characteristics | |
| Spectral type | DAP8.9 |
| Apparent magnitude (B) | 14.69 |
| Apparent magnitude (V) | 14.10 |
| Apparent magnitude (R) | 14.0 |
| Apparent magnitude (I) | 13.6 |
| Apparent magnitude (J) | 12.930 ± 0.022 |
| Apparent magnitude (H) | 12.720 ± 0.025 |
| Apparent magnitude (K) | 12.653 ± 0.024 |
| Astrometry | |
| Radial velocity (Rv) | −414.02±10.41 km/s |
| Proper motion (μ) | RA: -444.685 mas/yr Dec.: -925.140 mas/yr |
| Parallax (π) | 123.1989±0.0170 mas |
| Distance | 26.474 ± 0.004 ly (8.117 ± 0.001 pc) |
| Absolute magnitude (MV) | 14.59 |
| Details | |
| Mass | 0.71 ± 0.03 M☉ |
| Radius | 0.011 R☉ |
| Surface gravity (log g) | 8.20 ± 0.05 cgs |
| Temperature | 5790 ± 110 K |
| Age | 3.97 Gyr |
| Other designations | |
| V1201 Ori, GJ 1087, EGGR 290, G 99-47, G 102-40, G 106-15, LHS 212, LTT 17891, NLTT 15834, WD 0553+053, 2MASS J05562547+0521486, USNO-B1.0 0953-00073703 | |
| Database references | |
| SIMBAD | data |
G 99-47 (V1201 Orionis) is a nearby degenerate star (white dwarf) of spectral class DAP8 (DAP8.9, or DAP8.7), the single known component of the system, located in the constellation Orion. G 99-47 is the 10th-closest known white dwarf, the next closest after LP 658-2 and GJ 3991 B.
The mass of G 99-47 is 0.71±0.03 Solar masses; its surface gravity is 108.20 ± 0.05 (1.58 · 108) cm·s−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, 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. Due almost equal to the Sun's temperature, GJ 1087 should appear almost the same white color as the Sun. The white dwarf has a strong magnetic field, with measured vertical component near surface equal to 560 T.