Jovian stratospheric temperature during the two months following the impacts of comet Shoemaker-Levy 9

We present millimeter heterodyne observations of Jupiter performed at the I RAM 30-m telescope during and immediately after the infall of comet Shoemak er-Levy 9 on the planet. Rotational lines of CO and CS were first observed in emission during the impacts. They faded rapidly and turned into absorpti on features after July 28, 1994. The shapes of the lines imply that persist ent layers of newly created molecular compounds remained in the upper strat osphere. Modeling of these lines was performed by taking into account the s pecific geometry of the impact sites. The main results concern: (i) the CO mass at the impact site G 10.5 h after impact, which is found in the range 0.5-2 x 10(14) g, iii the CS mass derived on the Q1+R+S complex, which is b etween 0.9 and 2.5 x 10(12) g one week after the impacts, (iii) the tempora l evolution of the stratospheric temperature through July and September 199 4. Assuming an exponential decrease of the perturbed temperature in the upp er stratosphere, a cooling time constant of 29 h is found for the 10-mu bar region. Moreover, the temperature near 10-mu bar became colder than in pre -impact conditions between 2 and 3 weeks after the impacts, before returnin g to unperturbed values. Comparison is presented with published temperature evolution models of the SL9 sites. (C) 2001 Elsevier Science Ltd. All righ ts reserved.