504 Cora

Cora (minor planet designation: 504 Cora), provisional designation, is a metallic asteroid from the middle region of the asteroid belt, approximately 30 kilometers in diameter. It was discovered by American astronomer Solon Bailey at Harvard's Boyden Station in Arequipa, Peru, on 30 June 1902. It was later named after Cora, a figure in Inca mythology.

Classification and orbit
Cora orbits the Sun in the middle main-belt at a distance of 2.1–3.3 AU once every 4 years and 6 months (1,640 days). Its orbit has an eccentricity of 0.22 and an inclination of 13° with respect to the ecliptic. The body's observation arc begins 4 years after its discovery with the first used observation made at Heidelberg in 1906.

Spectral type
On the Tholen taxonomic scheme, as well as by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), Cora is classified as a metallic M-type asteroid.

Mineralogic observations in the near-infrared with the NASA IRTF telescope using its SpeX spectrograph, showed that its surface is that of an X-type asteroid, with absorption features indicating the presence of pyroxene minerals. In 2004, the body's spectrum was also obtained in the SMASSII survey at the U.S. MDM Observatory, Kitt Peak, Arizona.

Rotation period
Several rotational lightcurves of Cora were obtained for this asteroid by astronomers Maria A. Barucci, David Higgins, Axel Martin, and the Palomar Transient Factory. With one exception, they all gave a rotation period close to 7.59 hours. Among these, David Higgins' observation made in September 2010, at the Hunters Hill Observatory (E14) in Ngunnawal, Australia – gave the best rated lightcurve with a period of $27.19$ hours and a brightness variation of 0.20 magnitude (U=3-).

Diameter and albedo
According to the space-based surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and NASA's WISE telescope with its subsequent NEOWISE mission, Cora's surface has a high albedo between 0.239 and 0.341. Combined with their respective absolute magnitudes, this results in a diameter estimate of 27.2 to 35.0 kilometers. In contrast, the Collaborative Asteroid Lightcurve Link derives a much lower albedo of 0.19 and a diameter of 29.1 kilometers, based on an absolute magnitude of 10.1.

Naming
This minor planet was named after Cora, a figure in Inca mythology (AN&thinsp;169).