REENTRY AND ABLATION OF COMETARY DUST IN THE IMPACT PLUMES OF SHOEMAKER-LEVY-9

Citation
A. Fitzsimmons et al., REENTRY AND ABLATION OF COMETARY DUST IN THE IMPACT PLUMES OF SHOEMAKER-LEVY-9, Nature, 379(6568), 1996, pp. 801-804
Citations number
17
Categorie Soggetti
Multidisciplinary Sciences
Journal title
NatureACNP
ISSN journal
00280836
Volume
379
Issue
6568
Year of publication
1996
Pages
801 - 804
Database
ISI
SICI code
0028-0836(1996)379:6568<801:RAAOCD>2.0.ZU;2-1
Abstract
Collisions between small bodies (such as asteroids and comets) and the terrestrial planets are known to throw ejecta far beyond the point of impact. But until the fragments of comet Shoemaker-Levy 9 hit Jupiter in July 1994 (refs 1, 2), there had been no opportunity to study the effects of such collisions on gas-giant planets. Here we present optic al spectra obtained during the collision of fragments L and Q(1), with Jupiter. We observed emission lines from sodium, magnesium, calcium, iron, manganese and chromium as the ejecta plume fell back onto Jupite r's atmosphere. All of these elements are expected to occur only very deep in Jupiter's atmosphere-considerably below the depth to which the fragments penetrated--, suggesting that the material responsible for the emissions originated almost entirely in the comet itself. The init ial. phase of emission is associated with heating of the impact ejecta as it fell back onto the planet. A second, later phase of emission wa s also observed, which we associate with grains of silicate dust that condensed within the cooling fireball and subsequently re-entered, met eor-like, into Jupiter's atmosphere.