194 Prokne
Prokne (minor planet designation: 194 Prokne) is a main-belt asteroid that was discovered by German-American astronomer C. H. F. Peters on March 21, 1879, in Clinton, New York, and named after Procne, the sister of Philomela in Greek mythology. Stellar occultations by Prokne have been observed twice, in 1984 from Italy and again in 1999 from Iowa (United States). Observations from the W. M. Keck Observatory show the asteroid to be around 151 km across, with a size ratio of between the major and minor axes. For comparison, observations by the IRAS observatory gave a diameter  of 164 km. The spectrum matches a classification of a C-type asteroid, indicating it has a primitive carbonaceous composition. Judging from radar data, the near surface solid density of the asteroid is 3.6. Based upon a light curve that was generated from photometric observations of this asteroid at Pulkovo Observatory, it has a rotation period of hours and varies in brightness by in magnitude.