A group of asteroids that cross the Earth’s orbit, and whose average distances from the Sun are less than that of Earth; along with the more abundant Apollo group, they are termed Earth-crossing asteroids. Their aphelia are greater than 0.983 au (Earth’s perihelion distance) and their orbital periods are shorter than 1 year. The group is named after (2062) Aten, the first of the group to be discovered, by the American astronomer Eleanor Kay Helin, née Francis (1932–2009), in 1976. It is an S-type asteroid of diameter about 1 km. Aten's orbit has a semimajor axis of 0.967 au, period 0.95 years, perihelion 0.79 au, aphelion 1.14 au, and inclination 18°.9. Other major members of the group include (3753) Cruithne, diameter 3 km; Hathor; and Ra-Shalom. As of 2017, over 1100 Aten asteroids were known.