ESO 439-26 was considered the least luminous white dwarf known.[2][7] Located 140 light years away from the Sun, it is roughly 10 billion years old and has a temperature of 4560 Kelvin. Thus, despite being classified as a "white dwarf", it would actually appear yellowish in color.[8]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Hydra |
| Right ascension | 11h 39m 03.1036679378s[1] |
| Declination | −28° 52′ 16.627821186″[1] |
| Apparent magnitude (V) | 20.52[2] |
| Characteristics | |
| Spectral type | DC9[2] |
| U−B color index | 1.03[3] |
| B−V color index | 0.64[3] |
| R−I color index | 1.14[3] |
| Astrometry | |
| Proper motion (μ) | RA: -397.767 ±0.481[4] mas/yr Dec.: + 36.869 ±0.441[4] mas/yr |
| Parallax (π) | 9.7390 ± 0.5007 mas[4] |
| Distance | 330 ± 20 ly (103 ± 5 pc) |
| Absolute magnitude (MV) | 15.46[2][4] |
| Details | |
| Mass | 0.499397 ±0.150755[5] M☉ |
| Radius | 0.0126[6] R☉ |
| Luminosity | 1.15 ×10−5 [3] L☉ |
| Surface gravity (log g) | 7.866295 ±0.282184[5] cgs |
| Temperature | 4,672.65±274.68[5] K |
| Other designations | |
Ruiz 439-26, WD 1136-286[1] | |
| Database references | |
| SIMBAD | data |
This finding is however based on a too large parallax. Gaia measurement of the parallax shows a more distant source and therefore an absolute magnitude of MG=15.0 mag. For example the white dwarf WD J2147–4035 has MG=17.7 mag, making this white dwarf less luminous.[9][5] The updated MV is 15.46, using the Gaia parallax[4] and the apparent V-magnitude from Ruiz et al. (see formulae at the article absolute magnitude).[2]
References
edit- ^ a b c "Ruiz 439-26". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 22, 2020.
- ^ a b c d e María Teresa Ruiz; P. Bergeron; S. K. Leggett; Claudio Anguita (1995). "The Extremely Low Luminosity White Dwarf ESO 439-26". The Astrophysical Journal. 455. Bibcode:1995ApJ...455L.159R. doi:10.1086/309845. S2CID 120193018.
- ^ a b c d Bergeron, P.; Leggett, S. K.; Ruiz, María Teresa (April 2001). "Photometric and Spectroscopic Analysis of Cool White Dwarfs with Trigonometric Parallax Measurements". Astrophysical Journal Supplement Series. 133 (2): 413–449. arXiv:astro-ph/0011286. Bibcode:2001ApJS..133..413B. doi:10.1086/320356. S2CID 15511301.
- ^ a b c d e 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.
- ^ a b c d Gentile Fusillo, N. P.; Tremblay, P. -E.; Cukanovaite, E.; Vorontseva, A.; Lallement, R.; Hollands, M.; Gänsicke, B. T.; Burdge, K. B.; McCleery, J.; Jordan, S. (2021-12-01). "A catalogue of white dwarfs in Gaia EDR3". Monthly Notices of the Royal Astronomical Society. 508 (3): 3877–3896. arXiv:2106.07669. Bibcode:2021MNRAS.508.3877G. doi:10.1093/mnras/stab2672. ISSN 0035-8711.
- ^ Ruiz, Maria Teresa; Bergeron, P.; Leggett, S. K.; Anguita, Claudio (1995-12-01). "The Extremely Low Luminosity White Dwarf ESO 439-26". The Astrophysical Journal. 455: L159. doi:10.1086/309845. ISSN 0004-637X.
- ^ "The Faintest Known White Dwarf". www.noao.edu. 1 March 1996. Archived from the original on 12 March 2021. Retrieved 8 May 2020.
- ^ Kaler, James B. (May 7, 2006). The Hundred Greatest Stars. Springer Science & Business Media. ISBN 9780387216256 – via Google Books.
- ^ Elms, Abbigail K.; Tremblay, Pier-Emmanuel; Gänsicke, Boris T.; Koester, Detlev; Hollands, Mark A.; Gentile Fusillo, Nicola Pietro; Cunningham, Tim; Apps, Kevin (2022-12-01). "Spectral analysis of ultra-cool white dwarfs polluted by planetary debris". Monthly Notices of the Royal Astronomical Society. 517 (3): 4557–4574. arXiv:2206.05258. Bibcode:2022MNRAS.517.4557E. doi:10.1093/mnras/stac2908. ISSN 0035-8711.
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