Asteroid 2212, a member of the Apollo group, discovered in 1978 by the Russian astronomer Lyudmila Ivanovna Chernykh (1935–2017). Hephaistos is 5.7 km in diameter. Its orbit has a semimajor axis of 2.16 au, period 3.17 years, perihelion 0.35 au, aphelion 3.97 au, and inclination 11°.6. These orbital elements are similar to those of Comet Encke, and it has been speculated that Hephaistos and Comet Encke, as well as some other asteroids in similar orbits, may be remnants of a giant comet which split up within the past 20 000 years.