LSPM J0207+3331
Artist's impression using the old interpretation of a two ring disk. Newer analysis favour a single ring.[1] Credit: NASA’s Goddard Space Flight Center/Scott Wiessinger | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Triangulum[2] |
| Right ascension | 02h 07m 33.8061s[3] |
| Declination | +33° 31′ 29.542″[3] |
| Characteristics | |
| Evolutionary stage | white dwarf |
| Spectral type | DZA[1] |
| 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[3] Dec.: −25.850(202) mas/yr[3] |
| Parallax (π) | 22.4986±0.1563 mas[3] |
| Distance | 145 ± 1 ly (44.4 ± 0.3 pc) |
| Details[1] | |
| 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[4] | |
| 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.[5][6] The white dwarf accreted a massive differentiated rocky body with a large planetary core.[1] 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.[7][8]
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).[9] 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.[1]
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.[1]
Debris disk
The white dwarf has a circumstellar disk despite being 3 billion years old. The infrared excess in the spectrum was first interpreted as two separate rings.[9] Later it was however found that this feature is caused by silicate dust in a single ring, lying between 36 and 54.1 RWD and having a mass of 5.4 × 1019 g.[1] It may be a debris disk created from an asteroid broken apart by the star's gravity.[9] The mass of heavy elements in the convective zone of the white dwarf is currently 1.22 × 1022 g, which is the lower limit of the parent body mass. This parent body would be larger than 225 km.[1]
One work used photometry of the Astrophysical Observatory of Javalambre of the J-PLUS survey to predict a 89.7% chance of the white dwarf having absorption due to calcium.[10] Later 13 heavy elements were found in spectroscopic observations with Lick Observatory, Magellan Baade Telescope and Keck I telescope. The lack of molecular CH suggests a body depleted in carbon-volatiles. The composition is earth-like, with an enhanced abundance of siderophilic elements. The researchers interpret this as a massive differentiated rocky body with a large core (mass fraction of 55%) that got accreted.[1]
It is only the 5th white dwarf with detected strontium, showing that this element is preferably detected in cooler white dwarfs. Strontium has a short sinking time of around 35,000 years, showing that accretion is ongoing on LSPM J0207+3331. It is also only the second white dwarf with calcium H+K line core emission, likely originating in the upper atmosphere of the white dwarf. The researchers suggest this hints at additional physical processes that require future investigation.[1]
Models predict only a low rate of asteroids to be disrupted by an old white dwarf. The 1 Gyr simulations by Debes et al. found that only one asteroid per simulation was disrupted 200 Myrs after the white dwarf has formed.[11] The presence of a disk around a 3 Gyr white dwarf sets new demands for models that seek to explain dust around white dwarfs.[9]
Two-ring model
An early interpretation was that the disk did compose of two rings. Newer analysis interpret the 11.6 μm emission in WISE data as silicate emission. James Webb Space Telescope spectroscopy is needed to confirm this interpretation and to study the mineralogy of the parent body.[1]
The inner disk is optically thick with an inner radius of 0.047 R☉ and an outer radius of 0.21 R☉. The outer disk is optically thin. It is located near the Roche radius at around 0.94 R☉ and has a mass of a small asteroid or comet. This suggests that the outer disk formed relative recently from a tidal disruption of such a small body. If this outer disk is confirmed, it would be the first known dusty white dwarf with a two-component ring system.[9] Alternatively the gap in the disk could be explained by a dense exoplanet orbiting inside the disk and clearing a gap, or a planet orbiting outside the disk and opening a gap via resonant dynamics.[12] Due to the inner edge of the inner disk being located near the sublimation radius of fayalite and iron, it is suggested that the inner disk is composed of these materials. It is however not excluded that forsterite is a component of the inner disk.[12]
See also
Other old and cold white dwarfs with planetary debris:
- Van Maanen 2 (6,130 K)
- WD J2356−209 (4,040 K)
- WD 2317+1830 (4,557 K)
- WD J2147–4035 (3,050 K)
Other white dwarfs polluted by more than one minor planet:
- WD 1337+705 polluted by an iron-rich body and an ice-rich body
References
- ^ a b c d e f g h i j k Érika Le Bourdais; Dufour, Patrick; Melis, Carl; Klein, Beth L.; Rogers, Laura K.; Bédard, Antoine; Debes, John; Messier, Ashley; Weinberger, Alycia J.; Xu, Siyi (2025). "Tracing Planetary Accretion in a 3 Gyr-old Hydrogen-Rich White Dwarf: The Extremely Polluted Atmosphere of LSPM J0207+3331". arXiv:2510.08676 [astro-ph.SR].
- ^ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
- ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ "LSPM J0207+3331". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2025-06-13.
- ^ "Volunteer Discovers Record-Setting White Dwarf Star". NASA.gov. 19 February 2019. Retrieved 22 February 2019.
- ^ "Citizen Scientists Invited to Join Quest for New Worlds". NOAO. Retrieved 22 February 2019.
- ^ Hollands, Mark A.; Tremblay, Pier-Emmanuel; Gänsicke, Boris T.; Koester, Detlev; Gentile-Fusillo, Nicola Pietro (2021-05-01). "Alkali metals in white dwarf atmospheres as tracers of ancient planetary crusts". Nature Astronomy. 5 (5): 451–459. arXiv:2101.01225. Bibcode:2021NatAs...5..451H. doi:10.1038/s41550-020-01296-7. ISSN 2397-3366.
- ^ Bergeron, P.; Kilic, Mukremin; Blouin, Simon; Bédard, A.; Leggett, S. K.; Brown, Warren R. (2022-07-01). "On the Nature of Ultracool White Dwarfs: Not so Cool after All". The Astrophysical Journal. 934 (1): 36. arXiv:2206.03174. Bibcode:2022ApJ...934...36B. doi:10.3847/1538-4357/ac76c7. ISSN 0004-637X.
- ^ a b c d e Debes, John H.; Thevenot, Melina; Kuchner, Marc; Burgasser, Adam; Schneider, Adam; Meisner, Aaron; Gagne, Jonathan; Faherty, Jaqueline K.; Rees, Jon M.; Allen, Michaela; Caselden, Dan; Cushing, Michael; Wisniewski, John; Allers, Katelyn; The Backyard Worlds: Planet 9 Collaboration; The Disk Detective Collaboration (2019). "A 3 Gyr White Dwarf with Warm Dust Discovered via the Backyard Worlds: Planet 9 Citizen Science Project". The Astrophysical Journal. 872 (2): L25. arXiv:1902.07073. Bibcode:2019ApJ...872L..25D. doi:10.3847/2041-8213/ab0426. S2CID 119359995.
{{cite journal}}: CS1 maint: numeric names: authors list (link) - ^ López-Sanjuan, C.; Tremblay, P.-E.; O'Brien, M. W.; Spinoso, D.; Ederoclite, A.; Vázquez Ramió, H.; Cenarro, A. J.; Marín-Franch, A.; Civera, T.; Carrasco, J. M.; Gänsicke, B. T.; Gentile Fusillo, N. P.; Hernán-Caballero, A.; Hollands, M. A.; del Pino, A. (November 2024). "J-PLUS: The fraction of calcium white dwarfs along the cooling sequence". Astronomy and Astrophysics. 691: A211. arXiv:2406.16055. Bibcode:2024A&A...691A.211L. doi:10.1051/0004-6361/202451226. ISSN 0004-6361.
- ^ Debes, John H.; Walsh, Kevin J.; Stark, Christopher (2012-03-01). "The Link between Planetary Systems, Dusty White Dwarfs, and Metal-polluted White Dwarfs". The Astrophysical Journal. 747 (2): 148. arXiv:1201.0756. Bibcode:2012ApJ...747..148D. doi:10.1088/0004-637X/747/2/148. ISSN 0004-637X. S2CID 118688656.
- ^ a b Steckloff, Jordan K.; Debes, John; Steele, Amy; Johnson, Brandon; Adams, Elisabeth R.; Jacobson, Seth A.; Springmann, Alessondra (2021-04-28). "How Sublimation Delays the Onset of Dusty Debris Disk Formation around White Dwarf Stars". The Astrophysical Journal Letters. 913 (2): L31. arXiv:2104.14035. Bibcode:2021ApJ...913L..31S. doi:10.3847/2041-8213/abfd39. PMC 8740607. PMID 35003618.