Gliese 318

Gliese 318
Observation data
Epoch J2000      Equinox J2000
Constellation Pyxis
Right ascension 08h 41m 32.42908s[1]
Declination –32° 56′ 32.9158″[1]
Apparent magnitude (V) 11.85[2]
Characteristics
Spectral type DA5.5
U−B color index −0.59[3]
B−V color index +0.25[4]
Astrometry
Radial velocity (Rv)+29.3 ± 2.9 km/s
Proper motion (μ) RA: –1061.158 mas/yr[1]
Dec.: 1345.900 mas/yr[1]
Parallax (π)117.3961 ± 0.0205 mas[1]
Distance27.783 ± 0.005 ly
(8.518 ± 0.001 pc)
Absolute magnitude (MV)12.14 ± 0.05[5]
Details
Mass0.45 ± 0.01[5] M☉
Luminosity0.0015[5] L☉
Temperature9120 ± 190[5] K
Age550 ± 20 million[5] years
Other designations
GJ 318, CD−32° 5613, LHS 253, L 532-81, LTT 3218, WD 0839-327
Database references
SIMBADdata
ARICNSdata

Gliese 318 is a white dwarf in the constellation Pyxis. Its spectral type is DA5.5 and it has a visual magnitude of 11.85,[2] and lies 27.8 light-years (8.5 parsecs) away.[6] The star was too faint to have had its parallax measured by the Hipparcos satellite. Earth-based measurement in 2009 gave its parallax as 113.63 ± 1.97 milliarcseconds, yielding a distance of 28.7 ± 0.5 light-years;[5] this parallax measurement has since been substantially improved by Gaia. It is around 45% as massive as the Sun but has only 0.15% its luminosity.[5]

Bragaglia et al. suspect this star to be a double white dwarf due to strong spectral line variations.[7] From Gaia DR2 it was not possible to confirm this claim. It is still possible that Gliese 318 is a double white dwarf and additional spectroscopic observations are needed in order to confirm this claim.[8] Gliese 318 could be the closest double white dwarf to earth.[9][10]

  1. ^ a b c d Cite error: The named reference GaiaDR3 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Gaia was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference 2MASS was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference EgUBV was invoked but never defined (see the help page).
  5. ^ a b c d e f g Cite error: The named reference Subasavage was invoked but never defined (see the help page).
  6. ^ Sion, Edward M. (2009). "1.The White Dwarfs Within 20 Parsecs of the Sun: Kinematics and Statistics". The Astronomical Journal. 138 (6): 1681. arXiv:0910.1288. Bibcode:2009AJ....138.1681S. doi:10.1088/0004-6256/138/6/1681. S2CID 119284418.
  7. ^ Bragaglia, Angela; Greggio, Laura; Renzini, Alvio; D'Odorico, Sandro (1990-12-01). "Double Degenerates among DA White Dwarfs". The Astrophysical Journal. 365: L13. Bibcode:1990ApJ...365L..13B. doi:10.1086/185877. ISSN 0004-637X. Archived from the original on 2023-04-25. Retrieved 2023-04-25.
  8. ^ Hollands, M. A.; Tremblay, P. -E.; Gänsicke, B. T.; Gentile-Fusillo, N. P.; Toonen, S. (2018-11-01). "The Gaia 20 pc white dwarf sample". Monthly Notices of the Royal Astronomical Society. 480 (3): 3942–3961. arXiv:1805.12590. Bibcode:2018MNRAS.480.3942H. doi:10.1093/mnras/sty2057. ISSN 0035-8711.
  9. ^ Toonen, S.; Hollands, M.; Gänsicke, B. T.; Boekholt, T. (2017-06-01). "The binarity of the local white dwarf population". Astronomy and Astrophysics. 602: A16. arXiv:1703.06893. Bibcode:2017A&A...602A..16T. doi:10.1051/0004-6361/201629978. ISSN 0004-6361.
  10. ^ Bagnulo, S.; Landstreet, J. D. (2021-11-01). "New insight into the magnetism of degenerate stars from the analysis of a volume-limited sample of white dwarfs". Monthly Notices of the Royal Astronomical Society. 507 (4): 5902–5951. arXiv:2106.11109. Bibcode:2021MNRAS.507.5902B. doi:10.1093/mnras/stab2046. ISSN 0035-8711.