Gliese 521

Gliese 521
Observation data
Epoch J2000      Equinox J2000
Constellation Canes Venatici
Right ascension 13h 39m 24.10228s
Declination +46° 11 11.3631
Apparent magnitude (V) +10.26
Characteristics
Spectral type M1V
Apparent magnitude (J) 7.05
Apparent magnitude (H) 6.51
Apparent magnitude (K) 6.26
Astrometry
Radial velocity (Rv)−65.72±0.15 km/s
Proper motion (μ) RA: −42.332±0.012 mas/yr
Dec.: 389.167±0.014 mas/yr
Parallax (π)74.7985±0.0153 mas
Distance43.605 ± 0.009 ly
(13.369 ± 0.003 pc)
Absolute magnitude (MV)10.243
Details
Mass0.506±0.021 M
0.47±0.05 M
Radius0.619±0.030 R
0.47±0.05 R
Luminosity0.033+0.008
−0.007
 L
Surface gravity (log g)4.79±0.04 cgs
Temperature3,493±50 K
Metallicity [Fe/H]−0.34 dex
−0.09±0.09 dex
Rotation49.5±3.5 d
Rotational velocity (v sin i)0.85 km/s
Other designations
BD+46 1889, GJ 521, HIP 66625, SAO 44697, WDS 13394+4611, LTT 13979, TYC 3463-00063-1, 2MASS J13392410+4611114
Database references
SIMBADdata

Gliese 521 is a double star in the northern constellation of Canes Venatici. The system is located at a distance of 43.6 light-years from the Sun based on parallax measurements, but is drawing closer with a radial velocity of −65.6 km/s. It is predicted to come as close as 15.70 light-years from the Sun in 176,900 years. This star is too faint to be visible to the naked eye, having an apparent visual magnitude of +10.26 and an absolute magnitude of 10.24.

The primary is an M-type main-sequence star with a stellar classification of M1V. It is only about half the size and mass of the Sun. The star is rotating slowly with a projected rotational velocity of 0.85 km/s and a rotation period of roughly 49.5 days. The star has a lower metal-content compared to the Sun. It is radiating just 3% of the luminosity of the Sun from its photosphere at an effective temperature of 3,493 K.

A faint stellar companion was announced by E. Jódar and associates in 2013. The companion has an angular separation of 521 mas along a position angle of 352.1°±1.4° from the primary. This is equivalent to a projected separation of 7.24±0.14 AU.