LSPM J0207+3331
Artist's impression using the old interpretation of a two ring disk. Newer analysis favour a single ring. Credit: NASA’s Goddard Space Flight Center/Scott Wiessinger | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Triangulum |
| Right ascension | 02h 07m 33.8061s |
| Declination | +33° 31′ 29.542″ |
| Characteristics | |
| Evolutionary stage | white dwarf |
| Spectral type | DZA |
| 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 | |
| Proper motion (μ) | RA: 169.843(151) mas/yr Dec.: −25.850(202) mas/yr |
| Parallax (π) | 22.4986±0.1563 mas |
| Distance | 145 ± 1 ly (44.4 ± 0.3 pc) |
| Details | |
| Mass | 0.656±0.029 M☉ |
| Radius | 0.0118±0.0004 R☉ |
| Surface gravity (log g) | 8.11±0.03 cgs |
| Temperature | 5910±98 K |
| Age | 3.08±0.32 Gyr |
| Other designations | |
| 2MASS J02073383+3331296, Gaia DR3 325899163483416704 | |
| Database references | |
| SIMBAD | data |
LSPM J0207+3331 is a cold and old white dwarf that hosts 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. The white dwarf accreted a massive differentiated rocky body with a large planetary core. Until 2021 it was the oldest and coldest white dwarf known to host a disk. The white dwarf WD 2317+1830 with a detected disk is at least twice as old and around 2,000 K colder.
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). The optical spectrum shows that the white dwarf atmosphere is polluted with 13 heavy elements, accreted from the disk into the white dwarf atmosphere. This is the highest number of elements found in a white dwarf with a hydrogen atmosphere.
The white dwarf formed around 3.1 billion years from a star with a mass of 1.86±0.44 M☉. This star had a lifetime of 1.54+1.92
−0.56 billion years.