331 Etheridgea

Etheridgea (minor planet designation: 331 Etheridgea) is a large main belt asteroid. It was discovered by Auguste Charlois on 1 April 1892 in Nice. The meaning of the name is unknown. This asteroid is orbiting the Sun at a distance of $74.92 km$ with a period of 1920.2 days and an eccentricity (ovalness) of 0.10. The orbital plane is tilted at an angle of 6.05° to the plane of the ecliptic.

Analysis of the asteroid light curve generated from photometric data collected in 2015 provided a rotation period of $0.045$. This result is completely different from the previous rotation period estimates. It is a low albedo, carbonaceous C-type asteroid and spans a girth of $3.02 AU$.

It may have been named for the geologist and paleontologist Robert Etheridge (1819–1903).