WD J2356−209
| Observation data Epoch J2000.0 (ICRS) Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Vela |
| Right ascension | 23h 56m 45.576s[1] |
| Declination | −20° 54′ 45.01″[1] |
| Characteristics | |
| Spectral type | DC[2] or DZ[3] |
| Astrometry | |
| Distance | 211.3 ± 8.2 ly (64.8 ± 2.5 pc)[3] ly |
| Details | |
| Surface gravity (log g) | 8.26±0.15[3] cgs |
| Temperature | 4,310±190[3] K |
| Age | 8.0±0.8[3] Gyr |
| Database references | |
| SIMBAD | data |
WD J2356−209 (also known as WD 2354−211)[4] is a white dwarf star located 65 pc (212 ly) away from the Earth.[5] It is a very faint white dwarf, with an apparent visual magnitude of 21.03.[6] Its visible spectrum is dominated by a broad absorption feature[2] that has been attributed to pressure-broadened sodium D lines.[7] The presence of this sodium absorption feature and the detection of spectral lines from other heavy elements (calcium, iron and magnesium) indicate that the photosphere of WD J2356−209 has been polluted by a recent rocky debris accretion episode. A detailed analysis of the spectrum of WD J2356−209 shows that the accreted planetesimal was abnormally sodium-rich, containing up to ten times more sodium than calcium.[3] With an effective temperature of 4040 K, WD J2356−209 is the coolest metal-polluted white dwarf observed to date (and also the oldest, with a white dwarf cooling age of about 8 Gyr).[3]
References[]
- ^ a b Lasker, Barry M.; et al. (August 2008). "The Second-Generation Guide Star Catalog: Description and Properties". The Astronomical Journal. 136 (2): 735–766. arXiv:0807.2522. Bibcode:2008AJ....136..735L. doi:10.1088/0004-6256/136/2/735.
- ^ a b Oppenheimer, B. R.; et al. (22 March 2001). "Direct Detection of Galactic Halo Dark Matter". Science. 292 (5517): 698–702. arXiv:astro-ph/0104293. doi:10.1126/science.1059954. PMID 11264524.
- ^ a b c d e f g Blouin, S.; Dufour, P.; Allard, N. F.; Salim, S.; Rich, R. M.; Koopmans, L. V. E. (February 2019). "A New Generation of Cool White Dwarf Atmosphere Models. III. WD J2356-209: Accretion of a Planetesimal with an Unusual Composition". The Astrophysical Journal. 872 (2): 188. arXiv:1902.03219. Bibcode:2019ApJ...872..188B. doi:10.3847/1538-4357/ab0081.
- ^ "WD 2354-211". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-01-16.
- ^ Gaia Collaboration (2016). "The Gaia mission". Astronomy and Astrophysics. 595: A1. arXiv:1609.04153. doi:10.1051/0004-6361/201629272.
- ^ Bergeron, P.; et al. (June 2005). "On the Interpretation of High‐Velocity White Dwarfs as Members of the Galactic Halo". The Astrophysical Journal. 625 (2): 838–848. arXiv:astro-ph/0502350. Bibcode:2005ApJ...625..838B. doi:10.1086/429715.
- ^ Salim, Samir; Rich, R. Michael; Hansen, Brad M.; Koopmans, L. V. E.; Oppenheimer, Ben R.; Blandford, Roger D. (February 2004). "Cool White Dwarfs Revisited: New Spectroscopy and Photometry". The Astrophysical Journal. 601 (2): 1075–1087. arXiv:astro-ph/0308126. Bibcode:2004ApJ...601.1075S. doi:10.1086/380581.
External links[]
- Too much sodium turns a star blue 25 February 2019, Nathalie Ouellette
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