| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cetus | 
| Right ascension | 03h 02m 53.10375s [1] | 
| Declination | −01° 08′ 33.7987″ [1] | 
| Apparent magnitude (V) | 15.56 [2] | 
| Characteristics | |
| Spectral type | DB [2] | 
| Astrometry | |
| Parallax (π) | 15.3618±0.0456 mas [1] | 
| Distance | 212.3 ± 0.6  ly (65.1 ± 0.2 pc) | 
| Absolute magnitude (MV) | 11.30 [2] | 
| Details | |
| Mass | 0.59 [3] M☉ | 
| Radius | 0.01? R☉ | 
| Luminosity | 0.0068 [2] L☉ | 
| Surface gravity (log g) | 7.91 ± 0.18 [2] cgs | 
| Temperature | 15300 [3] K | 
| Age | 200 million years | 
| Other designations | |
| GD 40, EGGR 384, US 3562, WD 0300-019 | |
| Database references | |
| SIMBAD | data | 
GD 40 is a white dwarf in the constellation Cetus. It is located about 212 light-years (65 parsecs) away from the Sun. [1] The star's spectrum has been found to show traces of external of metal contamination due to disruption of an extrasolar dwarf planet or an asteroid. [3] The disrupted object should have had roughly the same mass of the Solar System asteroid 3 Juno.