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Gliese 318
Observation data; Epoch J2000 Equinox J2000
Constellation	Pyxis
Right ascension	08h 41m 32.42908s
Declination	–32° 56′ 32.9158″
Apparent magnitude (V)	11.85
Characteristics
Spectral type	DA5.5
U−B color index	−0.59
B−V color index	+0.25
Astrometry
Radial velocity (Rv)	+29.3 ± 2.9 km/s
Proper motion (μ)	RA: –1061.158 mas/yr ; Dec.: 1345.900 mas/yr
Parallax (π)	117.3961 ± 0.0205 mas
Distance	27.783 ± 0.005 ly ; (8.518 ± 0.001 pc)
Absolute magnitude (MV)	12.14 ± 0.05
Details
Mass	0.45 ± 0.01 M☉
Luminosity	0.0015 L☉
Temperature	9120 ± 190 K
Age	550 ± 20 million years
Other designations
	GJ 318, CD−32° 5613, LHS 253, L 532-81, LTT 3218, WD 0839-327
Database references
SIMBAD	data
ARICNS	data

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]

References

^ ^a ^b ^c ^d 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 Pancino, E.; Altavilla, G.; Marinoni, S.; Cocozza, G.; Carrasco, J. M.; Bellazzini, M.; Bragaglia, A.; Federici, L.; Rossetti, E.; Cacciari, C.; Balaguer Núñez, L.; Castro, A.; Figueras, F.; Fusi Pecci, F.; Galleti, S.; Gebran, M.; Jordi, C.; Lardo, C.; Masana, E.; Monguió, M.; Montegriffo, P.; Ragaini, S.; Schuster, W.; Trager, S.; Vilardell, F.; Voss, H. (2012). "The Gaia spectrophotometric standard stars survey - I. Preliminary results". Monthly Notices of the Royal Astronomical Society. 426 (3): 1767–81. arXiv:1207.6042. Bibcode:2012MNRAS.426.1767P. doi:10.1111/j.1365-2966.2012.21766.x. S2CID 27564967.
^ Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C. Archived from the original on 2021-04-21. Retrieved 2021-11-16.
^ Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M. Archived from the original on 2019-12-08. Retrieved 2017-03-12.
^ ^a ^b ^c ^d ^e ^f ^g Subasavage, John P.; Jao, Wei-Chun; Henry, Todd J.; Bergeron, P.; Dufour, P.; Ianna, Philip A.; Costa, Edgardo; Méndez, René A. (2009). "The Solar Neighborhood. XXI. Parallax Results from the CTIOPI 0.9 m Program: 20 New Members of the 25 Parsec White Dwarf Sample". The Astronomical Journal. 137 (6): 4547–60. arXiv:0902.0627. Bibcode:2009AJ....137.4547S. doi:10.1088/0004-6256/137/6/4547. S2CID 14696597.
^ 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.
^ 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.
^ 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.
^ 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.
^ 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.