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 03.1037s [1]
Declination −28° 52′ 16.628″ [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 0.50 ±0.15 [5]   M☉
Radius 0.0126 [6]   R☉
Luminosity 1.15 ×10−5 [3]   L☉
Surface gravity (log g)7.87 ±0.28 [5]   cgs
Temperature 4,673±275 [5]   K
Other designations
Ruiz 439-26, WD 1136-286 [1]
Database references
SIMBAD data

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

  1. 1 2 3 "Ruiz 439-26". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved October 22, 2020.
  2. 1 2 3 4 5 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. 1 2 3 4 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. 1 2 3 4 5 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. 1 2 3 4 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.
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