HD 59686

HD 59686
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Gemini
Right ascension 07h 31m 48.40415s
Declination +17° 05 09.7695
Apparent magnitude (V) +5.45
Characteristics
Evolutionary stage red clump
Spectral type K2III
B−V color index 1.126±0.006
Astrometry
Radial velocity (Rv)−33.55±0.18 km/s
Proper motion (μ) RA: +39.712 mas/yr
Dec.: -76.077 mas/yr
Parallax (π)11.1741±0.0911 mas
Distance292 ± 2 ly
(89.5 ± 0.7 pc)
Absolute magnitude (MV)0.52
Orbit
Period (P)11,680+234
−173
 d
Semi-major axis (a)13.56+0.18
−0.14
AU
Eccentricity (e)0.729+0.004
−0.003
Argument of periastron (ω)
(secondary)
149.4±0.2°
Semi-amplitude (K1)
(primary)
4.014+0.010
−0.008
km/s
Details
A
Mass1.43±0.23 M
Radius11.22±0.70 R
Luminosity57.5+14.9
−11.8
 L
Surface gravity (log g)2.63±0.09 cgs
Temperature4,670±34 K
Metallicity [Fe/H]0.01±0.03 dex
Rotational velocity (v sin i)1.03±0.23 km/s
Age2.73±1.11 Gyr
B
Mass≥0.53 M
Other designations
BD+17°1596, GC 10073, HD 59686, HIP 36616, HR 2877, SAO 96985, GSC 01364-01582
Database references
SIMBADdata

HD 59686 is a binary star system in the northern constellation of Gemini. It is visible to the naked eye as a dim point of light with an apparent visual magnitude of +5.45. The distance to this system is approximately 292 light years based on parallax, but it is drifting closer with a radial velocity of −34 km/s.

This is a single-lined spectroscopic binary system with an orbital period of 32.0 years and a high eccentricity of 0.73. The visible component is an aging giant star with a stellar classification of K2III. It is most likely fusing helium in its core in a position on the H-R diagram called the red clump. The stellar radius is very large: 11.2 times that of the Sun. The star is around 2.7 billion years old with 1.4 times the mass of the Sun. It is radiating 58 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,670 K.

The secondary component has a minimum mass 53% that of the Sun, which indicates it must be a star rather than a brown dwarf or a planet.