Phaethon approaches the Sun closer than any other numbered asteroid. Its perihelion (closest approach to the Sun) is only 0.140 AU – less than half Mercury's perihelion distance. It is a Mercury-, Venus-, Earth- and Mars-crosser. The surface temperature at perihelion could reach ~1025 K, or 1400 F. For this reason, it was named after the Greek myth of Phaëton, son of the sun god Helios.
Phaethon approached to 18.1 Gm on December 10,2007. It will draw nearer in 2017, 2050, 2060, and closer still on December 14, 2093, passing within 0.0198 AU (3.0 Gm).