Gliese 521
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 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 along a position angle of 352.1°° from the primary. This is equivalent to a projected separation of.