LSPM J0207+3331
LSPM J0207+3331 is, as of 2023, the oldest and coldest known white dwarf star to host a circumstellar disk, located 145 light-years from Earth. It was discovered in October 2018 by a volunteer participating in the Backyard Worlds citizen science project.
Artist's impression Credit: NASA’s Goddard Space Flight Center/Scott Wiessinger | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Triangulum |
| Right ascension | 02h 07m 33.8059837915s |
| Declination | +33 31 29.534350702 |
| Characteristics | |
| Evolutionary stage | white dwarf |
| Spectral type | DA |
| Apparent magnitude (g) | 17.86 ± 0.02 |
| Apparent magnitude (r) | 17.49 ± 0.02 |
| Apparent magnitude (i) | 17.34 ± 0.02 |
| Apparent magnitude (J) | 16.6±0.1 |
| Astrometry | |
| Parallax (π) | 22.44 ± 0.20 mas |
| Distance | 145 ± 1 ly (44.6 ± 0.4 pc) |
| Details | |
| Mass | 0.69+0.01 −0.02 M☉ |
| Radius | 0.011 R☉ |
| Surface gravity (log g) | 8.16±0.03 cgs |
| Temperature | 6120+48 −57 K |
| Age | 3±0.2 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The white dwarf has a radius of 0.011 R☉, which is about 1.2 times the radius of the earth. Because white dwarfs are such dense objects, LSPM J0207 has a mass of about 0.69 M☉. The presence of the Paschen Beta-Line in a near-infrared spectrum from the Keck telescope helped to determine that the atmosphere of LSPM J0207 is dominated by hydrogen (spectral type DA). Due to the inner disk around the white dwarf, it should be expected that the atmosphere has a lot of other elements and that the white dwarf is a metal-polluted white dwarf. To confirm this hypothesis, it is required to take an optical spectrum of the white dwarf.