Gliese 318
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pyxis |
| Right ascension | 08h 41m 32.42908s |
| Declination | −32° 56′ 32.9158″ |
| Apparent magnitude (V) | 11.85 |
| Characteristics | |
| Evolutionary stage | white dwarf |
| Spectral type | DA5.5 |
| U−B color index | −0.59 |
| B−V color index | +0.25 |
| Astrometry | |
| Radial velocity (Rv) | +29.3±2.9 km/s |
| Proper motion (μ) | RA: −1,061.158 mas/yr Dec.: +1,345.900 mas/yr |
| Parallax (π) | 117.3961±0.0205 mas |
| Distance | 27.783 ± 0.005 ly (8.518 ± 0.001 pc) |
| Absolute magnitude (MV) | 12.22±0.04 |
| Details | |
| Mass | 0.47±0.02 M☉ |
| Radius | 0.0148 ± 0.00092 R☉ |
| Luminosity | 1.32+0.13 −0.12×10−3 L☉ |
| Surface gravity (log g) | 7.77±0.03 cgs |
| Temperature | 9,040±190 K |
| Age | 590±40 Myr |
| Other designations | |
| GJ 318, CD−32°5613, LHS 253, L 532-81, LTT 3218, WD 0839-327 | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
Gliese 318 is a white dwarf in the constellation Pyxis. Its spectral type is DA5.5 and it has a visual magnitude of 11.85, and lies 27.8 light-years (8.5 parsecs) away.
The star was too faint to have had its parallax measured by the Hipparcos satellite. Earth-based measurement in 2009 gave its parallax as 113.63±1.97 milliarcseconds, yielding a distance of 28.7±0.5 light-years; this parallax measurement has since been substantially improved by Gaia.
Gliese 318 is a rather young white dwarf with an age estimated to be 590 million years. Its temperature is around 9,000 K and it shines with 0.13 percent of the luminosity of the Sun. Like all white dwarfs, Gliese 318 is small, with just 1.5 percent the Sun's radius (1.6 R🜨), but has around half the Sun's mass.
Bragaglia et al. suspect this star to be a double white dwarf due to strong spectral line variations. From Gaia DR2 it was not possible to confirm this claim. It is still possible that Gliese 318 is a double white dwarf and additional spectroscopic observations are needed in order to confirm this claim. Gliese 318 could be the closest double white dwarf to earth.