GD 165

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Coordinates: Sky map 14h 24m 39.144s, +09° 17′ 13.98″

GD 165
Observation data
Epoch J2000[1]      Equinox J2000[1]
Constellation Boötes
Right ascension  14h 24m 39.144s[1]
Declination 09° 17′ 13.98″[1]
Database references
GD 165 B

GD 165 is a system of a white dwarf and a brown dwarf of spectral types DA4[2] + L4,[3] located in constellation Boötes at approximately 103 light-years from Earth.[3]

Nomenclature and observation[edit]

"GD" means "Giclas Dwarf".[4]

The component GD 165 B was discovered in 1988 by Becklin and Zuckerman.[5] It is the first L-type brown dwarf, and in general, the first dwarf cooler than M dwarfs[6] discovered, but it was not recognized as a brown dwarf until the 1990s, when other such objects were found, starting from Gliese 229 B in 1995.[7][8]

Initially it was tentatively assigned spectral type ≥M10, but in 1999 Kirkpatrick et al. established new spectral types L and T for newly discovered objects cooler than M-type stars, and GD 165 B was reclassified L4.[3]


Currently the most precise distance estimate of GD 165 is the YPC trigonometric parallax, published by van Altena et al. in 1995: 31.7 ± 2.5 mas, corresponding to a distance 31.5+2.7
pc, or 102.9+8.8

GD 165 distance estimates

Source Parallax, mas Distance, pc Distance, ly Ref.
van Altena et al. (1995) 31.7 ± 2.5 31.5+2.7
Tinney et al. (1995) 25.4 ± 7.4 39.4+16.2

The best estimate is marked in bold.

Physical properties[edit]

Temperature of GD 165 B is 1800–1900 K.[3]

See also[edit]

The other later than M brown dwarfs, discovered before 1998:

Nakajima et al. (1995):[8]

Kirkpatrick et al. (1997):[2]

Delfosse et al. (1997):[11]

Ruiz et al. (1997):[12]

  • Kelu-1 (L2,[3] isolated, later a companion was found)


  1. ^ a b c d e "V* CX Boo -- Pulsating White Dwarf". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2013-09-23.
  2. ^ a b Kirkpatrick, J. Davy; Beichman, Charles A.; Skrutskie, Michael F. (1997). "The Coolest Isolated M Dwarf and Other 2MASS Discoveries". The Astrophysical Journal. 476: 311. Bibcode:1997ApJ...476..311K. doi:10.1086/303613.
  3. ^ a b c d e f g h i j k Kirkpatrick, J. D.; Reid, I. N.; Liebert, J.; Cutri, R. M.; Nelson, B.; Beichman, C. A.; Dahn, C. C.; Monet, D. G.; Gizis, J. E.; Skrutskie, M. F. (1999). "Dwarfs Cooler than "M": The Definition of Spectral Type "L" Using Discoveries from the 2 Micron All-Sky Survey (2MASS)" (PDF). The Astrophysical Journal. 519 (2): 802–833. Bibcode:1999ApJ...519..802K. doi:10.1086/307414.
  4. ^ Dictionary of Nomenclature of Celestial Objects. GD entry. SIMBAD. Centre de Données astronomiques de Strasbourg.
  5. ^ Becklin, E. E.; Zuckerman, B. (1988). "A low-temperature companion to a white dwarf star". Nature. 336 (Dec. 15, 1988): 656–658. Bibcode:1988Natur.336..656B. doi:10.1038/336656a0.
  6. ^ Dahn, C. C.; Harris, Hugh C.; Vrba, Frederick J.; Guetter, Harry H.; Canzian, Blaise; Henden, Arne A.; Levine, Stephen E.; Luginbuhl, Christian B.; Monet, Alice K. B.; Monet, David G.; Pier, Jeffrey R.; Stone, Ronald C.; Walker, Richard L.; Burgasser, Adam J.; Gizis, John E.; Kirkpatrick, J. Davy; Liebert, James; Reid, I. Neill (2002). "Astrometry and Photometry for Cool Dwarfs and Brown Dwarfs". The Astronomical Journal. 124 (2): 1170–1189. arXiv:astro-ph/0205050. Bibcode:2002AJ....124.1170D. doi:10.1086/341646.
  7. ^ Andrei, A. H.; Smart, R. L.; Penna, J. L.; d'Avila, V. A.; Bucciarelli, B.; Camargo, J. I. B.; Crosta, M. T.; Daprà, M.; Goldman, B.; Jones, H. R. A.; Lattanzi, M. G.; Nicastro, L.; Pinfield, D. J.; da Silva Neto, D. N.; Teixeira, R. (2011). "Parallaxes of Southern Extremely Cool Objects. I. Targets, Proper Motions, and First Results". The Astronomical Journal. 141 (2): 54. arXiv:1011.1378. Bibcode:2011AJ....141...54A. doi:10.1088/0004-6256/141/2/54.
  8. ^ a b Nakajima, T.; Oppenheimer, B. R.; Kulkarni, S. R.; Golimowski, D. A.; Matthews, K.; Durrance, S. T.; Neto, D. N.; Teixeira, R. (1995). "Discovery of a cool brown dwarf". Nature. 378 (6556): 463–465. Bibcode:1995Natur.378..463N. doi:10.1038/378463a0.
  9. ^ Tinney, C. G.; Reid, I. N.; Gizis, J.; Mould, J. R. (1995). "Trigonometric Parallaxes and the HR Diagram at the Bottom of the Main Sequence". The Astronomical Journal. 110: 3014. Bibcode:1995AJ....110.3014T. doi:10.1086/117743.
  10. ^ Burgasser, A. J.; Kirkpatrick, J. D.; Brown, M. E.; Reid, I. N.; Burrows, A.; Liebert, J.; Matthews, K.; Gizis, J. E.; Dahn, C. C.; Monet, D. G.; Cutri, R. M.; Skrutskie, M. F. (2002). "The Spectra of T Dwarfs. I. Near-Infrared Data and Spectral Classification". The Astrophysical Journal. 564 (1): 421–451. arXiv:astro-ph/0108452. Bibcode:2002ApJ...564..421B. doi:10.1086/324033.
  11. ^ Delfosse, X.; Tinney, C. G.; Forveille, T.; Epchtein, N.; Bertin, E.; Borsenberger, J.; Copet, E.; de Batz, B.; Fouque, P.; Kimeswenger, S.; Le Bertre, T.; Lacombe, F.; Rouan, D.; Tiphene, D. (1997). "Field brown dwarfs found by DENIS". Astronomy and Astrophysics. 327: L25–L28. Bibcode:1997A&A...327L..25D.
  12. ^ Ruiz, Maria Teresa; Leggett, S. K.; Allard, France (1997). "Kelu-1: A Free-floating Brown Dwarf in the Solar Neighborhood". The Astrophysical Journal Letters. 491: L107. Bibcode:1997ApJ...491L.107R. doi:10.1086/311070.