next up previous contents
Next: Heterodyne millimeter observations Up: Observation reports: Jupiter Previous: Observation reports: Jupiter

Interferometric Observations of HCN J=1-0 during the SL9 Crash on Jupiter

Report by: J. Wink, R. Lucas, S. Guilloteau and A. Dutrey
IRAM, Grenoble
We report here the detection of HCN J=1-0 after the crash of the comet Shoemaker-Levy 9 on Jupiter. The observations were performed with the IRAM Interferometer from July 16th to July 24th. Since Jupiter was strongly resolved by the interferometer beam but not by the primary beam, we chose to observe the planet center and we applied a very specific data reduction method. First, Jupiter was used to calibrate the radio frequency passband and the relative phase. Then the amplitude was calibrated by fitting spline functions to Jupiter visibilities. The data phases were then corrected for the position offset from the planet center to the impact site. To correct for residual instrumental ripples in the phase passband of the system, we finally added to the impact data, the data corresponding to the symmetrical point with respect to the planet center.

Figure 1: Plateau de Bure Interferometer J=1-0 HCN emission (Jy) observed on Fragment A on July 20th 1994. The geocentric velocities are corrected from Jupiter rotation.

In fig. 1, we present some preliminary results concerning fragment A on July 20th. The HCN J=1-0 line appears in emission and is particularly narrow: kms . Comparison with the HCN J=4-3 emission observed at the JCMT implies an optically thin J=1-0 line.

Robert Lucas
Thu Mar 9 12:42:24 MET 1995