Astronomy:Gliese 318

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Short description: White dwarf in the constellation Pyxis
Gliese 318
Observation data
Equinox J2000.0]] (ICRS)
Constellation Pyxis
Right ascension  08h 41m 32.42908s[1]
Declination −32° 56′ 32.9158″[1]
Apparent magnitude (V) 11.85[2]
Characteristics
Evolutionary stage white dwarf[3]
Spectral type DA5.5[3]
U−B color index −0.59[4]
B−V color index +0.25[5]
Astrometry
Radial velocity (Rv)+29.3±2.9 km/s
Proper motion (μ) RA: −1,061.158[1] mas/yr
Dec.: +1,345.900[1] mas/yr
Parallax (π)117.3961 ± 0.0205[1] mas
Distance27.783 ± 0.005 ly
(8.518 ± 0.001 pc)
Absolute magnitude (MV)12.22±0.04[6]
Details[6]
Mass0.47±0.02 M☉
Radius0.0148 ± 0.00092[lower-alpha 1] R☉
Luminosity1.32+0.13
−0.12×10−3 L☉
Surface gravity (log g)7.77±0.03 cgs
Temperature9,040±190 K
Age590±40[lower-alpha 2] Myr
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.[7]

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;[8] this parallax measurement has since been substantially improved by Gaia.

Gliese 318 is a rather young white dwarf with an age estimated to be 590 million years. Its temperature is around 9,000 K and it shines with 0.13 percent of the luminosity of the Sun. Like all white dwarfs, Gliese 318 is small, with just 1.5 percent the Sun's radius (1.6 R⊕),[lower-alpha 1] but has around half the Sun's mass.[6]

Bragaglia et al. suspect this star to be a double white dwarf due to strong spectral line variations.[9] 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.[10] Gliese 318 could be the closest double white dwarf to earth.[11][12]

Notes

  1. ↑ 1.0 1.1 1.2 Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:
    (5,7729,040)4⋅10−2.88=0.0148 R⊙.
  2. ↑ This is just the cooling age

References

  1. ↑ 1.0 1.1 1.2 1.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. ↑ 2.0 2.1 Pancino, E.; Altavilla, G.; Marinoni, S.; Cocozza, G.; Carrasco, J. M.; Bellazzini, M.; Bragaglia, A.; Federici, L. et al. (2012). "The Gaia spectrophotometric standard stars survey - I. Preliminary results". Monthly Notices of the Royal Astronomical Society 426 (3): 1767–81. doi:10.1111/j.1365-2966.2012.21766.x. Bibcode: 2012MNRAS.426.1767P. 
  3. ↑ 3.0 3.1 Gianninas, A.; Bergeron, P.; Ruiz, M. T. (2011). "A Spectroscopic Survey and Analysis of Bright, Hydrogen-rich White Dwarfs". The Astrophysical Journal 743 (2): 138. doi:10.1088/0004-637X/743/2/138. Bibcode: 2011ApJ...743..138G. 
  4. ↑ Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E. et al. (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. http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=II/246. Retrieved 2021-11-16. 
  5. ↑ Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode: 1986EgUBV........0M. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1. Retrieved 2017-03-12. 
  6. ↑ 6.0 6.1 6.2 Subasavage, John P. et al. (July 2017), "The Solar Neighborhood. XXXIX. Parallax Results from the CTIOPI and NOFS Programs: 50 New Members of the 25 parsec White Dwarf Sample", The Astronomical Journal 154 (1): 24, doi:10.3847/1538-3881/aa76e0, 32, Bibcode: 2017AJ....154...32S. 
  7. ↑ Sion, Edward M. (2009). "1.The White Dwarfs Within 20 Parsecs of the Sun: Kinematics and Statistics". The Astronomical Journal 138 (6): 1681. doi:10.1088/0004-6256/138/6/1681. Bibcode: 2009AJ....138.1681S. 
  8. ↑ 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. doi:10.1088/0004-6256/137/6/4547. Bibcode: 2009AJ....137.4547S. 
  9. ↑ Bragaglia, Angela; Greggio, Laura; Renzini, Alvio; D'Odorico, Sandro (1990-12-01). "Double Degenerates among DA White Dwarfs". The Astrophysical Journal 365: L13. doi:10.1086/185877. ISSN 0004-637X. Bibcode: 1990ApJ...365L..13B. https://ui.adsabs.harvard.edu/abs/1990ApJ...365L..13B. Retrieved 2023-04-25. 
  10. ↑ 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. doi:10.1093/mnras/sty2057. ISSN 0035-8711. Bibcode: 2018MNRAS.480.3942H. 
  11. ↑ 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. doi:10.1051/0004-6361/201629978. ISSN 0004-6361. Bibcode: 2017A&A...602A..16T. 
  12. ↑ 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. doi:10.1093/mnras/stab2046. ISSN 0035-8711. Bibcode: 2021MNRAS.507.5902B. 



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