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Entry Flashes of Cometary Fragments in Jovian Upper Atmosphere

Published online by Cambridge University Press:  14 August 2015

S. Takeuchi ,
H. Hasegawa  and
J. Watanabe
S. Takeuchi
Affiliation:
National Space Development Agency of Japan Sengen, Tsukuba, Ibaraki 305, Japan
H. Hasegawa
Affiliation:
ASTEC, Inc. Minami-cho, Shinjuku, Tokyo 162, Japan
J. Watanabe
Affiliation:
National Astronomical Observatory of Japan Osawa, Mitaka, Tokyo 181, Japan

Extract

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Short lasting flashes, called as First Precursor (PC1), were observed by some ground-based near-infrared observations for the impacts of large-sized fragments of comet Shoemaker-Levy 9 (SL9) in July 1994. The impact detections by the spacecraft Galileo [2, 7] about 10 seconds after the PC1 detections by ground based telescopes, combined with the far-side impacts of SL9 fragments as viewed from Earth, suggest that the source of the PC1 should be located in the Jovian upper atmosphere above the limb, at which the atmospheric pressure is extremely low. Thus, an important problem on the PC1 is how does the falling cometary fragment, which is a huge meteorite, emit near-infrared in the extremely thin atmosphere. The ablation model, which is usually used for an impact bolide, can only estimate flux from the bolide in a dense atmosphere at visible wavelength. In this paper, we assume that the PC1s are thermal radiation from the fragments and attempt quantitative estimations of the PCI fluxes using a simple entry flash model.

Type
II. Joint Discussions
Information
Highlights of Astronomy , Volume 11 , Issue 1: Highlights of Astronomy. As presented at the XXIIIrd General Assembly of the IAU (Part A), 1997 , 1998 , pp. 266 - 269
Copyright
Copyright © Kluwer 1998

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