helena (minor planet designation: 101 helena) is a large, rocky main-belt asteroid.it was discovered by canadian-american astronomer j. c. watson on august 15, 1868, and was named after helen of troy in greek mythology.this object is orbiting the sun with a period of 4.16 years and an eccentricity of 0.14.its orbital plane is inclined by 10.2° to the plane of the ecliptic.radar observations were made of this object on oct 7 and 19, 2001 from the arecibo observatory.analysis of the data gave an estimated ellipsoidal diameter of 71×63×63 ± 16% km.the mean diameter estimated from iras infrared measurements is 66 km, in agreement with the radar findings.it is classified as an s-type asteroid in the tholen system, suggesting a predominantly silicate composition.101 helena is spinning on its axis with a period of 23 hours.
101 helena | discoverer | james craig watson <tsp> james craig watson | nationality | canada
no related information