RITROVATO IL PIANETINO “HERMES” (1937 UB)
Il Pianetino 1937 UB (Hermes) che andò perduto subito dopo la scoperta avvenuta nel 1937.
E' stato riscoperto nel 2003 (fine Agosto), ma non si era certi che si trattasse
proprio di tale pianetino perché l' orbita iniziale era molto imprecisa,
inoltre tale orbita era, ed e', molto perturbata da Giove, Marte e dalla Terra
stessa.
Con le osservazioni del 15-10-2003 fatte da Pianoro , ed altre osservazioni
fatte da alti osservatori, e' stato possibile risalire all' identificazione.
Il documento allegato, in inglese, si riferisce a tale identificazione.
The orbit above is based on a computation linking the 1937 and 2003 observations by S. R. Chesley and P. W. Chodas of NASA's NEO Program Office at the Jet Propulsion Laboratory, Pasadena, California. They note that the trajectory of 1937 UB is very chaotic due to frequent and close planetari encounters. Between the 1937 October encounter at 0.00495 AU and the present encounter, 1937 UB made eight intervening close approaches to the Earth or Venus at distances less than 0.06 AU, includine an approach to within 0.0043 AU of Earth on 1942 April 26.7. These perturbations dramatically narrowed the region of convergence for differential corrections, so that very precise initial conditions were required to permit a least-squares fit. With the use of just the 2003 astrometry the JPL Sentry impact monitoring software (which was specifically developed to cope with such extreme nonlinearity) identified twelve dynamically distinct routes from 2003 to the 1937 encounter. Comparing target plane projections of these possibilities with that of the observed 1937 encounter enabled them to derive suitable initial conditions permitting a general orbital solution using all data, with appropriata weighting of the low-quality 1937 data.
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Animazione del pianetino Hermes ripresa da Vittorio Goretti |