Comet Tempel 1.
Comet Tempel 1 close up.
Comet Tempel 1.

Comet Tempel 1.

Courtesy of NASA/University of Maryland

http://nmp.jpl.nasa.gov/ds1/


Comet Tempel 1, discovered on April 3, 1867 by French astronomer Ernst Wilhelm Leberecht Tempel, had a period of 5.68 years when discovered, but its orbit occasionally brings it close enough to Jupiter to be altered, which happened in 1881when the orbital period increased to 6.5 years. Later close approaches to Jupiter in 1941 and 1953 decreased the orbital period ultimately to to 5.55 years. Its size was measured with Hubble Space Telescope and Spitzer Space Telescope to be 14 by 4 km (8.7 by 2.5 mi). A two-day rotation rate was also determined. Tempel 1 was impacted by the NASA Deep Impact probe, one day before its closet approach to the Sun, and formed a crater about 200 meters in diameter and 30-50 meters deep. Tempel 1 will be visited again in 2011 by the Stardust spacecraft