H1504+65
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ursa Minor |
| Right ascension | 15h 02m 09.6297s |
| Declination | +66° 12′ 19.1461″ |
| Apparent magnitude (V) | 15.9 |
| Characteristics | |
| Astrometry | |
| Proper motion (μ) | RA: −6.055±0.128 mas/yr Dec.: 8.106±0.112 mas/yr |
| Parallax (π) | 2.0573±0.0591 mas |
| Distance | 1,590 ± 50 ly (490 ± 10 pc) |
| Details | |
| Temperature | 200,000 K |
| Other designations | |
| WD 1501+663 | |
| Database references | |
| SIMBAD | data |
H1504+65 is an enigmatic peculiar star in the constellation Ursa Minor. With a surface temperature of 200,000 K (360,000°F) and an atmosphere composed of carbon, oxygen and 2% neon, it is the second hottest white dwarf ever discovered, with only RX J0439.8−6809 being hotter. It is thought to be the stellar core of a post-asymptotic giant branch star, though its composition is unexplainable by current models of stellar evolution.