HD 40409

HD 40409 is a suspected astrometric binary star system in the southern constellation of Dorado. It is a faint system but visible to the naked eye with an apparent visual magnitude of 4.65. Based upon an annual parallax shift of $1.022$, it is located 88 light years away from the Sun. It is moving further away with a heliocentric radial velocity of +25 km/s. The system has a relatively high proper motion, traversing the celestial sphere at the rate of $25.1$ per year along a position angle of 14.51°.

Based on the stellar classification of K2 III assigned by Gray et al. (2006), the visible component is a K-type giant star. In contrast, Keenan and McNeil (1989) gave it a somewhat less evolved classification of K2 III–IV. It is about eight billion years old with 12% more mass than the Sun, and has expanded to 4.8 times the Sun's radius. The star is radiating 11 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,858 K.