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Gd 165 across the universe
GD 165 is a system of a white dwarf and a brown dwarf of spectral types DA4 + L4, located in constellation Boötes at approximately 103 light-years from Earth.
Contents
- Gd 165 across the universe
- Name
- Discovery of component B
- Assignment of spectral type to component B
- Distance
- Physical properties
- References
Name
"GD" means "Giclas Dwarf".
Discovery of component B
GD 165 B was discovered in 1988 by Becklin and Zuckerman. It is the first L-type brown dwarf, and in general, the first dwarf cooler than M dwarfs 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.
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.
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.
GD 165 distance estimates
The best estimate is marked in bold.
Physical properties
Temperature of GD 165 B is 1800—1900 K.