Year: 1995
Type: article
Abstract: The I R T F carried out a wide variety of programs related to the impacts of comet P/Shoemaker-Levy 9 into Jupiter.Images of the comet showed t h a t fragment K had faded to invisibility in the J and K bandpasses a week before impact but there is a tentative detection of a feature that may be a much brighter fragment K a few hours before impact.Effects due to fragments B and F were undetectable near the limb of Jupiter using the MIRAC2 (Mid-InfarRed Array Camera 2 -built by the University of Arizona and the Smithsonian Astrophysical Observatory) at the same wavelengths used for studies of the effects of fragments C, G, and R. Lightcurves were obtained for the impact sites of fragment C at 2.248 /xm, of fragment G at several wavelenghts severely limited by fog, and of fragment R at 7.85, 10.3, and 12.2 \im.The emission at site R is thermal in origin although it may not have a black-body spectrum.Observations at 7.85 fim (dominated by CH 4 lines) show that the stratosphere above several sites was several K warmer than elsewhere one rotation after the impacts.The characteristic cooling time is about 2 days.Observations at wavelengths sensitive to the 150 to 400 mbar pressure levels showed several K enhancements, although site E was barely detectable.At 400 mbar, the temperature excess disappeared rapidly while at 150 mbar it remained visible for two weeks at site L.Emission by NH3 was strong over the impact sites with a different morphology than the thermal emission.The NH3 is estimated to be at the 1 to 30 mbar level.PH3 was either depleted or significantly warmed.A sharp emission line of CO was observed that is probably at the 10 yhar level and which requires enhanced CO in the stratosphere.Observations at 3.41, 2.27, and 2.10 fim show that the particles in the clouds must be at an altitude corresponding to no more t h a n a few mbar.The clouds are not visible at 1.60 fim, suggesting that their optical depth is small in the near infrared.The clouds above site K spread at a zonal speed of 6 m s _ 1 to yield a feature roughly 44deg in longitude and 15deg in latitude by July 28.This implies a decreasing velocity field with altitude.Prior to the impacts, the southern auroral zone had been slightly brighter available at https://www.
Source: Highlights of Astronomy
Institutions: University of Maryland, College Park, Jet Propulsion Laboratory, Goddard Space Flight Center, National Aeronautics and Space Administration, Massachusetts Institute of Technology, Northern Arizona University, University of Arizona, University of Hawaii System, University College London, Ames Research Center
Language: English
Topic: Astro and Planetary Science
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W126454125