Clyde Tombaugh : biography
Clyde William Tombaugh (February 4, 1906January 17, 1997) was an American astronomer. Although he is best known for discovering the dwarf planet Pluto in 1930, the first object to be discovered in what would later be identified as the Kuiper belt, Tombaugh also discovered many asteroids; he also called for the serious scientific research of unidentified flying objects.
Discovery of Pluto
While a young researcher working for the Lowell Observatory in Flagstaff, Arizona, Tombaugh was given the job to perform a systematic search for a trans-Neptunian planet (also called Planet X), which had been predicted by Percival Lowell and William Pickering.
Tombaugh used the observatory’s 13-inch astrograph to take photographs of the same section of sky several nights apart. He then used a blink comparator to compare the different images. When he shifted between the two images, a moving object, such as a planet, would appear to jump from one position to another, while the more distant objects such as stars would appear stationary. Tombaugh noticed such a moving object in his search, near the place predicted by Lowell, and subsequent observations showed it to have an orbit beyond that of Neptune. This ruled out classification as an asteroid, and they decided this was the ninth planet that Lowell had predicted. The discovery was made on Tuesday, February 18, 1930, using images taken the previous month. The name "Pluto" was reportedly suggested by Venetia Burney, then an 11-year-old English school girl, who died in April 2009, having lived to see the reclassification of Pluto as a dwarf planet. It won out over numerous other suggestions because it was the name of the Roman god of the underworld, who was able to render himself invisible, and because Percival Lowell’s initials PL formed the first 2 letters. The name Pluto was officially adopted on May 1, 1930.
Following the discovery, starting in the 1990s, of other Kuiper belt objects, Pluto began to be seen not as a planet orbiting alone at 40 AU, but as the largest of a group of icy bodies in that region of space. After it was shown that at least one such body was larger than Pluto, on August 24, 2006 the International Astronomical Union (IAU) reclassified Pluto, grouping it with two similarly sized "dwarf planets" rather than with the eight "classical planets".
Tombaugh’s widow Patricia stated after the IAU’s decision that while Clyde may have been disappointed with the change since he had resisted attempts to remove Pluto’s planetary status in his lifetime, he would have accepted the decision now if he were alive. She noted that he "was a scientist. He would understand they had a real problem when they start finding several of these things flying around the place."
Tombaugh discovered nearly 800 asteroids during his search for Pluto and years of follow-up searches looking for another candidate for the postulated Planet X. Tombaugh is also credited with the discovery of periodic comet 274P/Tombaugh–Tenagra. He also discovered hundreds of variable stars, as well as star clusters, galaxy clusters, and a galaxy supercluster.
|2839 Annette||October 5, 1929|
|2941 Alden||December 24, 1930|
|3310 Patsy||October 9, 1931|
|3583 Burdett||October 5, 1929|
|3754 Kathleen||March 16, 1931|
|3775 Ellenbeth||October 6, 1931|
|3824 Brendalee||October 5, 1929|
|4510 Shawna||December 13, 1930|
|4755 Nicky||October 6, 1931|
|5701 Baltuck||November 3, 1929|
|(6618) 1936 SO||September 16, 1936|
|7101 Aldering||October 17, 1930|
|7150 McKellar||October 11, 1929|
|(8778) 1931 TD|3}}||October 10, 1931|