3 Monocerotis

3 Monocerotis is a binary star system in the equatorial constellation of Monoceros, located approximately 780 light years away from the Sun based on parallax. It is visible to the naked eye as a faint, blue-white hued star with a combined apparent visual magnitude of 4.92. The system is moving further from the Earth with a heliocentric radial velocity of +39 km/s.

The magnitude 4.98 primary, designated component A, has a stellar classification of B5 III, matching an evolved blue giant star. It has 5.85 times the mass of the Sun and is radiating 1,105 times the Sun's luminosity from its photosphere at an effective temperature of 15,000 K. The companion, component B, is magnitude 7.96 with an angular separation of $-8.282$ from the primary.