GD 165 is a binary white dwarf and brown dwarf system located in the Boötes constellation, roughly 109 light-years from Earth.[7] Neither of the stars have any known exoplanets.
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] |
Characteristics | |
Evolutionary stage | white dwarf + brown dwarf |
Spectral type | DA4[2]+L4[3] |
Astrometry | |
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] |
Distance | 109.0 ± 0.2 ly (33.41 ± 0.06 pc) |
Details | |
GD 165 A | |
Mass | 0.64 ± 0.02[6] M☉ |
Radius | 0.0124 ± 0.0003[6] R☉ |
Luminosity | 0.0030 ± 0.0006[6] L☉ |
Surface gravity (log g) | 8.052 ± 0.035[6] cgs |
Temperature | 12,130 ± 450[6] K |
Rotation | 57.29 ± 0.34 hours[6] |
Age | 1.2-5.5[7] Gyr |
GD 165 B | |
Mass | 62.58 ± 15.57[8] MJup |
Radius | 1.00 ± 0.08[8] RJup |
Surface gravity (log g) | 5.19 ± 0.21[8] cgs |
Temperature | 1755 ± 102[8] K |
Age | 1.2-5.5[7] Gyr |
Other designations | |
Database references | |
SIMBAD | GD 165 A |
GD 165 B |
The system GD 165 is named after Henry L. Giclas, an American Astronomer who lived throughout the 20th century.[9]
GD 165 B was discovered in 1988 by Becklin and Zuckerman at the University of California, Los Angeles.[10] GD 165 B was the first brown dwarf discovered to be cooler than M-Type stars[11] and was initially assigned the spectral type ≥M10. It would not be recognized as a brown dwarf until 1999, when new spectral types L-Type and T-Type for objects cooler than M-type stars were established, reclassifying GD 165 B as L4.[3]
GD 165 A is a pulsating white dwarf with a temperature of about 12,100 K, a mass of 0.64 M☉, and a radius of 0.0124 R☉.[6] GD 165 A has an extremely dim luminosity of 0.0030L☉,[6] making it completely invisible to the naked eye.
GD 165 B is an L-Type Brown Dwarf with a temperature of about 1,750 K, a mass of about 63 MJ, and a radius of 1.00 RJ.[8] GD 165B is separated by 123±12 astronomical units from its host white dwarf. It is the second closest spacially resolved brown dwarf after PHL 5038, which has a separation of around 69 AU.[12] It produces almost no light and is completely invisible to the naked eye.
Other cooler than M brown dwarfs, discovered before 1998: