Gliese 65

Gliese 65 A/B
Gliese 65 is located in the constellation Cetus.
Gliese 65 is located in the constellation Cetus.
     Gliese 65
Location of Gliese 65 in the constellation Cetus

Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cetus
Gliese 65 A (BL Ceti)
Right ascension 01h 39m 01.3773s[1]
Declination –17° 57′ 02.587″[1]
Apparent magnitude (V) 12.8[2]
Gliese 65 B (UV Ceti)
Right ascension 01h 39m 01.6377s[3]
Declination –17° 57′ 01.001″[3]
Apparent magnitude (V) 12.8[2]
Characteristics
Gliese 65 A (BL Ceti)
Spectral type M5.5V[4]
U−B color index 1.10
B−V color index 1.87
Variable type UV Cet[5]
Gliese 65 B (UV Ceti)
Spectral type M6 V[4]
Variable type UV Cet[6]
Astrometry
Parallax (π)371.92 ± 0.42 mas[7]
Distance8.770 ± 0.010 ly
(2.689 ± 0.003 pc)
Gliese 65 A (BL Ceti)
Proper motion (μ) RA: 3385.316[1] mas/yr
Dec.: 544.386[1] mas/yr
Absolute magnitude (MV)15.7[2]
Gliese 65 B (UV Ceti)
Proper motion (μ) RA: 3178.694[3] mas/yr
Dec.: 584.061[3] mas/yr
Absolute magnitude (MV)15.7[2]
Orbit[7]
Period (P)26.38±0.002 yr
Semi-major axis (a)2.0584±0.0097[8]"
(5.459±0.002 AU)
Eccentricity (e)0.6172±0.0001
Inclination (i)128.0±0.1°
Longitude of the node (Ω)325.9±0.1°
Periastron epoch (T)41333±8 MJD
(17 January 1972)
Argument of periastron (ω)
(secondary)		103.2±0.1°
Details
Gliese 65 A
Mass0.122±0.002[7] M☉
Radius0.165±0.006[8] R☉
Luminosity0.00147±0.00005[9] L☉
Surface gravity (log g)5.092±0.015[8] cgs
Temperature2784±58[9] K
Metallicity [Fe/H]−0.03±0.20[8] dex
Rotation0.2430±0.0005[10] days
Rotational velocity (v sin i)28.2±2[8] km/s
Gliese 65 B
Mass0.116±0.002[7] M☉
Radius0.159±0.006[8] R☉
Luminosity0.00125±0.00005[9] L☉
Surface gravity (log g)5.113±0.015[8] cgs
Temperature2728±60[9] K
Metallicity [Fe/H]−0.12±0.20[8] dex
Rotation0.2268±0.0003[10] days
Rotational velocity (v sin i)30.6±2[8] km/s
Other designations
GJ 65, G 272-61, L 726-8, PLX 343.1
Gliese 65 A: BL Ceti, LHS 9, LP 768-27
Gliese 65 B: UV Ceti, LHS 10, LP 768-26
Database references
SIMBADThe system
A (BL Cet)
B (UV Cet)

Gliese 65, also known as Luyten 726-8, is a binary star system that is one of Earth's nearest neighbors, at 8.8 light-years (2.7 parsecs) from Earth in the constellation Cetus. The two component stars are both flare stars with the variable star designations BL Ceti and UV Ceti.

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