1604 Tombaugh
1604 Tombaugh, provisional designation, is a rare-type Eos asteroid from the outer region of the asteroid belt, approximately 32 kilometers in diameter. It was discovered on 24 March 1931, by American astronomer Carl Otto Lampland at Lowell Observatory in Flagstaff, Arizona, in the United States. It was named after the discoverer of Pluto, Clyde Tombaugh.
Classification and orbit
Tombaugh is a member of the Eos family that orbits the Sun in the outer main-belt at a distance of 2.7–3.3 AU once every 5 years and 3 months. Its orbit has an eccentricity of 0.10 and an inclination of 9° with respect to the ecliptic. Its observation arc begins at Flagstaff, one year prior to its official discovery observation at Lowell Observatory. It had been previously identified at Heidelberg as in 1920, and as in 1930.Physical characteristics
Tombaugh is classified as an X-type asteroid. It is also classified as a rare XSCU type in the Tholen, and as a transitional Xc type in the SMASS taxonomy.Rotation period
In April 2010 and November 2012, rotational lightcurves of Tombaugh were obtained from photometric observations at Oakley Southern Sky Observatory, Australia, and at Bassano Bresciano Observatory, Italy. Lightcurve analysis gave a rotation period of 7.047 and 7.056 hours with a brightness variation of 0.16 and 0.35 magnitude, respectively.These periods supersede previous results obtained by astronomers Claes-Ingvar Lagerkvist, Richard P. Binzel and Krisztián Sárneczky.