GD 165

Coordinates: Sky map 14h 24m 39.144s, +09° 17′ 13.98″
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GD 165
GD 165.png
The white dwarf GD 165 A is seen in the center of the image as a bright star. The brown dwarf GD 165 B is below the white dwarf, seen as a red spot.
Observation data
Epoch J2000[1]      Equinox J2000[1]
Constellation Boötes
Right ascension 14h 24m 39.144s[1]
Declination 09° 17′ 13.98″[1]
Evolutionary stage white dwarf + brown dwarf
Spectral type DA4[2]+L4[3]
Radial velocity (Rv)-26.8 ± 4.3[4] km/s
Proper motion (μ) RA: -213.353 ± 0.084[5] mas/yr
Dec.: -149.648 ± 0.074[5] mas/yr
Parallax (π)29.9335 ± 0.0559 mas[5]
Distance109.0 ± 0.2 ly
(33.41 ± 0.06 pc)
GD 165 A
Mass0.64 ± 0.02[6] M
Radius0.0124 ± 0.0003[6] R
Luminosity0.0030 ± 0.0006[6] L
Surface gravity (log g)8.052 ± 0.035[6] cgs
Temperature12,130 ± 450[6] K
Rotation57.29 ± 0.34 hours[6]
Age1.2-5.5[7] Gyr
GD 165 B
Mass62.58 ± 15.57[8] MJup
Radius1.00 ± 0.08[8] RJup
Surface gravity (log g)5.19 ± 0.21[8] cgs
Temperature1755 ± 102[8] K
Age1.2-5.5[7] Gyr
Other designations
LSPM J1424+0917, 2MASS J14243914+0917139, WDS J14247+0917A, WD 1422+095, V* CX Boo, ** ZUC 12
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] GD 165 B remained the only brown dwarf companion of a white dwarf until the discovery of GD 1400 B, which was discovered 17 years later.[9]

Nomenclature and observation[edit]

"GD" means "Giclas Dwarf".[10]

The component GD 165 B was discovered in 1988 by Becklin and Zuckerman.[11] It is the first L-type brown dwarf, and in general, the first dwarf cooler than M dwarfs[12] 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.[13][14]

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]


As of 1999 the most precise distance estimate of GD 165 was 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
ly.[3] In 2018 ESA's Gaia satellite measured the parallax of the system with high precision.[5]

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
Gaia Collaboration (2018) 29.9335 ± 0.0559 33.4 109 [5]

Physical properties[edit]

A broad band optical light curve for GD 165, adapted from Giammichele et al. (2015)[6]

The white dwarf GD 165 A is classical ZZ Ceti variable with a temperature of about 12 100 K and a mass of 0.64 M.[6]

GD 165 B has a temperature of about 1750 K and a mass of about 63 MJ.[8] Like all L-dwarfs GD 165 B lacks the dominant titanium oxide seen in warmer M dwarfs. The depletion of titanium oxide is caused by the formation of perovskite grains in the photospheres of L-dwarfs.[16] Lithium is not detected in the spectrum of this L-dwarf, but considering the age of the system and the mass of the brown dwarf, any lithium should be destroyed, whether GD 165 B is a brown dwarf or not.[7]

See also[edit]

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

Nakajima et al. (1995):[14]

Kirkpatrick et al. (1997):[2]

Delfosse et al. (1997):[18]

Ruiz et al. (1997):[19]

  • 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 c Kirkpatrick, J. Davy; Beichman, Charles A.; Skrutskie, Michael F. (1997). "The Coolest Isolated M Dwarf and Other 2MASS Discoveries". The Astrophysical Journal. 476 (1): 311–318. Bibcode:1997ApJ...476..311K. doi:10.1086/303613.
  3. ^ a b c d e f g h i j k Kirkpatrick, J. Davy; Reid, I. Neill; Liebert, James; Cutri, Roc M.; Nelson, Brant; Beichman, Charles A.; Dahn, Conard C.; Monet, David G.; Gizis, John E.; Skrutskie, Michael 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. S2CID 73569208.
  4. ^ Pauli, E.-M.; Napiwotzki, R.; Heber, U.; Altmann, M.; Odenkirchen, M. (February 2006). "3D kinematics of white dwarfs from the SPY project. II". Astronomy & Astrophysics. 447 (1): 173–184. arXiv:astro-ph/0510494. Bibcode:2006A&A...447..173P. doi:10.1051/0004-6361:20052730. ISSN 0004-6361.
  5. ^ a b c d e Gaia Collaboration (2018-08-01). "Gaia Data Release 2 - Summary of the contents and survey properties". Astronomy & Astrophysics. 616: A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. ISSN 0004-6361. S2CID 49211658.
  6. ^ a b c d e f g h Giammichele, N.; Fontaine, G.; Brassard, P.; Charpinet, S. (March 2016). "A New Analysis of the Two Classical ZZ Ceti White Dwarfs GD 165 and Ross 548. II. Seismic Modeling". Astrophysical Journal Supplement Series. 223 (1): 10. Bibcode:2016ApJS..223...10G. doi:10.3847/0067-0049/223/1/10. ISSN 0067-0049. S2CID 124354534.
  7. ^ a b c Kirkpatrick, J. Davy; Allard, France; Bida, Tom; Zuckerman, Ben; Becklin, E. E.; Chabrier, Gilles; Baraffe, Isabelle (July 1999). "An Improved Optical Spectrum and New Model FITS of the Likely Brown Dwarf GD 165B". Astrophysical Journal. 519 (2): 834–843. Bibcode:1999ApJ...519..834K. doi:10.1086/307380. ISSN 0004-637X.
  8. ^ a b c d e Filippazzo, Joseph C.; Rice, Emily L.; Faherty, Jacqueline; Cruz, Kelle L.; Van Gordon, Mollie M.; Looper, Dagny L. (September 2015). "Fundamental Parameters and Spectral Energy Distributions of Young and Field Age Objects with Masses Spanning the Stellar to Planetary Regime". Astrophysical Journal. 810 (2): 158. arXiv:1508.01767. Bibcode:2015ApJ...810..158F. doi:10.1088/0004-637X/810/2/158. ISSN 0004-637X. S2CID 89611607.
  9. ^ Farihi, J.; Christopher, M. (October 2004). "A Possible Brown Dwarf Companion to the White Dwarf GD 1400". The Astronomical Journal. 128 (4): 1868–1871. arXiv:astro-ph/0407036. Bibcode:2004AJ....128.1868F. doi:10.1086/423919. ISSN 0004-6256. S2CID 119530628.
  10. ^ Dictionary of Nomenclature of Celestial Objects. GD entry. SIMBAD. Centre de Données astronomiques de Strasbourg.
  11. ^ 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. S2CID 4358564.
  12. ^ 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. S2CID 119485007.
  13. ^ 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. S2CID 7184822.
  14. ^ 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. S2CID 4351772.
  15. ^ 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.
  16. ^ Allard, France; Hauschildt, Peter H.; Alexander, David R.; Tamanai, Akemi; Schweitzer, Andreas (July 2001). "The Limiting Effects of Dust in Brown Dwarf Model Atmospheres". Astrophysical Journal. 556 (1): 357–372. arXiv:astro-ph/0104256. Bibcode:2001ApJ...556..357A. doi:10.1086/321547. ISSN 0004-637X. S2CID 14944231.
  17. ^ Burgasser, Adam J.; Kirkpatrick, J. Davy; Brown, Michael E.; Reid, I. Neill; Burrows, Adam; Liebert, James; Matthews, Keith; Gizis, John E.; Dahn, Conard C.; Monet, David G.; Cutri, Roc M.; Skrutskie, Michael 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. S2CID 9273465.
  18. ^ Delfosse, Xavier; Tinney, Chris G.; Forveille, Thierry; Epchtein, Nicolas; Bertin, Emmanuel; Borsenberger, Jean; Copet, Éric; de Batz, Bertrand; Fouqué, Pascal; Kimeswenger, Stefan; Le Bertre, Thibaut; Lacombe, François; Rouan, Daniel; Tiphène, Didier (1997). "Field brown dwarfs found by DENIS". Astronomy and Astrophysics. 327: L25–L28. Bibcode:1997A&A...327L..25D.
  19. ^ 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 (2): L107–L110. Bibcode:1997ApJ...491L.107R. doi:10.1086/311070.