Astronomy:WD 2317+1830
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Pegasus |
| Right ascension | 23h 17m 26.74s |
| Declination | +18° 30′ 52.76″ |
| Characteristics | |
| Evolutionary stage | white dwarf |
| Spectral type | DZ[1] |
| Apparent magnitude (G) | 19.35[2] |
| Astrometry | |
| Radial velocity (Rv) | 25 ±31[3] km/s |
| Proper motion (μ) | RA: -33.855 ±0.317[2] mas/yr Dec.: -452.811 ±0.263[2] mas/yr |
| Parallax (π) | 26.4097 ± 0.3090[2] mas |
| Distance | 123 ± 1 ly (37.9 ± 0.4 pc) |
| Details | |
| Mass | 1.076+0.007 −0.008[4] M☉ |
| Radius | 0.00793 ±0.00021[3] R☉ |
| Surface gravity (log g) | 8.64 ±0.03[3] cgs |
| Temperature | 4557 ±63[4] K |
| Age | cooling age: 6.388[4] Gyr total age: 7.7+0.3 −0.4[5] Gyr |
| Other designations | |
SDSS J231726.72+183049.6, EQ J2317+1830, Gaia DR2 2818957013992481280 | |
| Database references | |
| SIMBAD | data |
WD 2317+1830 (SDSS J231726.72+183049.6) is one of the first white dwarfs with lithium detected in its atmosphere. The white dwarf is surrounded by a debris disk and is actively accreting material. Researchers suggest that the presence of alkali metals indicates the accretion of crust material.[6][3] Another work however cautions to use alkali metals as a single indicator of crust material. They suggest that such objects could be polluted by mantle material instead.[7][8] An analysis in 2024 finds that the abundance of lithium is in agreement with Big Bang nucleosynthesis (BBN) and galactic nucleosynthesis. WD 2317+1830 likely was a star with sub-solar metallicity, which is evident from its old age, as well as from its thick disk or halo kinematics. This low metallicity means that the planetesimals that formed around this old white dwarf had a composition more similar to BBN abundances. The lithium-enhancement is not in agreement with the accretion of terrestrial continental crust material. The accretion of an exotic exoplanet is not ruled out, but the accretion of a primitive planetesimal is more likely. The accretion of an exomoon as a lithium source is excluded.[5]
WD 2317+1830 was first discovered in 2021 from Gaia and SDSS data as a candidate white dwarf.[9] A first spectral analysis was published in 2020, identifying it as a DZ white dwarf.[1] In 2021 observations with the Gran Telescopio Canarias were published. The white dwarf is massive and has a mass of 1.00 ± 0.02 M☉. The cooling age was determined to be 9.5±0.2 Gyrs and the total age is 9.7±0.2 Gyrs.[3] A more recent work found a higher temperature and younger cooling age of about 6.4 Gyrs.[4] The researchers detected sodium, lithium and weak calcium absorption. The researchers also detected infrared excess, indicative of a debris disk, around this white dwarf. The disk is inclined by 70°, has an inner disk temperature of 1,500 K and an outer disk temperature of 500 K. In the past WD 2317+1830 had a mass of 4.8 ± 0.2 M☉ and was likely a B-type star.[3]
See also
- List of exoplanets and planetary debris around white dwarfs
- WD J2356−209 is another cool white dwarf with sodium detected
- LSPM J0207+3331 is another old white dwarf with a disk detected
References
- ↑ 1.0 1.1 Tremblay, P. -E.; Hollands, M. A.; Gentile Fusillo, N. P.; McCleery, J.; Izquierdo, P.; Gänsicke, B. T.; Cukanovaite, E.; Koester, D. et al. (2020-09-01). "Gaia white dwarfs within 40 pc - I. Spectroscopic observations of new candidates". Monthly Notices of the Royal Astronomical Society 497 (1): 130–145. doi:10.1093/mnras/staa1892. ISSN 0035-8711. Bibcode: 2020MNRAS.497..130T.
- ↑ 2.0 2.1 2.2 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 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. doi:10.1038/s41550-020-01296-7. ISSN 2397-3366. Bibcode: 2021NatAs...5..451H. https://ui.adsabs.harvard.edu/abs/2021NatAs...5..451H/abstract.
- ↑ 4.0 4.1 4.2 4.3 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. doi:10.3847/1538-4357/ac76c7. ISSN 0004-637X. Bibcode: 2022ApJ...934...36B.
- ↑ 5.0 5.1 Kaiser, Benjamin C.; Clemens, J. Christopher; Blouin, Simon; Dennihy, Erik; Dufour, Patrick; Hegedus, Ryan J.; Reding, Joshua S. (2025). "The Origins of Lithium Enhancement in Polluted White Dwarfs". The Astrophysical Journal 979 (2): 111. doi:10.3847/1538-4357/ad9a6d. Bibcode: 2025ApJ...979..111K.
- ↑ University of Warwick. "Vaporised crusts of Earth-like planets found in dying stars" (in en). https://warwick.ac.uk/newsandevents/pressreleases/vaporised_crusts_of.
- ↑ Putirka, Keith D.; Xu, Siyi (2021-11-01). "Polluted white dwarfs reveal exotic mantle rock types on exoplanets in our solar neighborhood". Nature Communications 12 (1): 6168. doi:10.1038/s41467-021-26403-8. ISSN 2041-1723. PMID 34728614. Bibcode: 2021NatCo..12.6168P.
- ↑ info@noirlab.edu. "Rocky Exoplanets Are Even Stranger Than We Thought - A new astrogeology study suggests that most nearby rocky exoplanets are quite unlike anything in our Solar System" (in en). https://noirlab.edu/public/news/noirlab2127/.
- ↑ Gentile Fusillo, N. P.; Tremblay, P. -E.; Cukanovaite, E.; Vorontseva, A.; Lallement, R.; Hollands, M.; Gänsicke, B. T.; Burdge, K. B. et al. (2021-12-01). "A catalogue of white dwarfs in Gaia EDR3". Monthly Notices of the Royal Astronomical Society 508 (3): 3877–3896. doi:10.1093/mnras/stab2672. ISSN 0035-8711. Bibcode: 2021MNRAS.508.3877G.
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