GD 165

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

GD 165

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

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]

History of observations

Name

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

Discovery of component B

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 object were found, starting from Gliese 229 B in 1995.^[7][8]

Assignment of spectral type to component B

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 to L4.^[3]

Distance

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
−2.3 pc, or 102.9+8.8
−7.5 ly.^[3]

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 −2.3	102.9+8.8 −7.5	[3]
Tinney et al. (1995)	25.4 ± 7.4	39.4+16.2 −8.9	128.4+52.8 −29.0	[9][1]

The best estimate is marked in bold.

Physical properties

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

See also

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

Nakajima et al. (1995):^[8]

• Gliese 229 B (T6.5,^[10] a companion to a red dwarf star)

Kirkpatrick et al. (1997):^[2]

• 2MASP J0345432+254023 (L0,^[3] first isolated L-dwarf)

Delfosse et al. (1997):^[11]

• DENIS-P J020529.0-115925 (L7,^[3] isolated, later a companion was found)
• DENIS-P J1058.7-1548 (L3,^[3] isolated)
• DENIS-P J1228.2-1547 (L5,^[3] isolated, later a companion was found)

Ruiz et al. (1997):^[12]

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

References

1. "V* CX Boo -- Pulsating White Dwarf". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2013-09-23.
2. 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. 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)". 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. 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.