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ESO 439-26

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ESO 439-26
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]
Distance330 ± 20 ly
(103 ± 5 pc)
Absolute magnitude (MV)15.46[2][4]
Details
Mass0.499397 ±0.150755[5] M
Radius0.0126[6] R
Luminosity1.15 ×10−5 [3] L
Surface gravity (log g)7.866295 ±0.282184[5] cgs
Temperature4,672.65±274.68[5] K
Other designations
Ruiz 439-26, WD 1136-286[1]
Database references
SIMBADdata

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]

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]
  1. ^ a b c "Ruiz 439-26". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved October 22, 2020.
  2. ^ 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.
  3. ^ 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.
  4. ^ 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.
  5. ^ 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.
  6. ^ 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.
  7. ^ "The Faintest Known White Dwarf". www.noao.edu. 1 March 1996. Archived from the original on 12 March 2021. Retrieved 8 May 2020.
  8. ^ Kaler, James B. (May 7, 2006). The Hundred Greatest Stars. Springer Science & Business Media. ISBN 9780387216256 – via Google Books.
  9. ^ 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.