ABSTPJCT TIMMI is the ESO infrared camera dedicated to 10 jim high angular resolution imaging of the austral sky. This camera, built for the European Southern Observatory (ESO) by the Service d'Astrophysique at Saclay (SAp), has been successfully commissioned during 2 observing runs at the ESO 3.6-rn telescope: one in july 92 and the other in january 93. Based on a LIR 64*64 pixel Si:Ga/DVR detector array optimized for ground-based broad-band 10-jim astronomical observations, the camera, operated at a frame rate of 120 Hz, has achieved a noise equivalent flux density of 0.01 Jy m1n1"2 pixel1 (la) during N2-band observations with a pixel field of view of 0.48 arcsec. Two other fields of view are available: 0.32 and 0.65 arcsec. A filter wheel allows to select between 14 broad-band and narrow-band filters covering the atmospheric window (8-13 jim) ; a M filter allows observations in the 4 im atmospheric window with substantial sensitivity. The instrument is now available to visiting astronomers.
Light curves of the 12 µm emission following the collision of Shoemaker‐Levy 9 fragments A, E, H, L, Q1 with Jupiter are presented. Impacts F, P2, Q2, T, U were monitored, but not detected. The observations were carried out with the Saclay CAMIRAS camera mounted on the 2.56 m Nordic Optical Telescope located at La Palma (Canary Island, Spain).
Of particular interest is the light curve of the L impact (the brightest impact), where 3 different regions can be observed. A precursor flash (the debris cloud rising above the limb) is detected about 1 min 30 s after the detection from the Galileo spacecraft. Twelve minutes later, a huge infrared spot at a temperature of about 700 K appears at its peak intensity: 13 000 Jy. A new change of behaviour is observed 20 min after impact: a secondary bump appears, after which the flux decreases at a slower rate. Light curves of impacts Q1, H, E and A, up to more than one order of magnitude fainter than the L impact, are quite similar.
Ballistic re‐entry of dust‐gas in the atmosphere must be considered in the interpretation of the IR spot.
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