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The 10 October 1999 HIP 9369 occultation by the northern polar region of Jupiter: ingress and egress lightcurves analysis
The occultation of bright star HIP9369 by the northern polar region ofJupiter was observed from four locations in North and South America,providing four data sets for ingress and egress. The inversion of theeight occultation lightcurves provides temperature profiles at differentlatitudes ranging from 55°N to 73.2°N. We estimate the errors onthe profiles due to the uncertainties of the inversion method andcompare the value of the temperature at the deepest level probed (~ 50μbar) with previous observations. The shape of the temperaturegradient profile is found similar to previous investigations ofplanetary atmospheres with propagating and breaking gravity waves. Weanalyze the small scale structures in both lightcurves and temperatureprofiles using the continuous wavelet transform. The calculated powerspectra of localized fluctuations in the temperature profiles showslopes close to -3 for all eight profiles. We also isolate andreconstruct the three-dimensional geometry of a single wave mode withvertical and horizontal wavelengths of respectively 3 and 70 km. Theidentified wave is consistent with the gravity wave regime, with ahorizontal phase speed nearly parallel to the planetary meridian.Nevertheless, the dissipation of the corresponding wave in Jupiter'sstratosphere should preclude its detection at the observed levels and anacoustic wave cannot be ruled out.
| The Tokyo PMC catalog 90-93: Catalog of positions of 6649 stars observed in 1990 through 1993 with Tokyo photoelectric meridian circle
The sixth annual catalog of the Tokyo Photoelectric Meridian Circle(PMC) is presented for 6649 stars which were observed at least two timesin January 1990 through March 1993. The mean positions of the starsobserved are given in the catalog at the corresponding mean epochs ofobservations of individual stars. The coordinates of the catalog arebased on the FK5 system, and referred to the equinox and equator ofJ2000.0. The mean local deviations of the observed positions from theFK5 catalog positions are constructed for the basic FK5 stars to comparewith those of the Tokyo PMC Catalog 89 and preliminary Hipparcos resultsof H30.
| The occultation of SAO 78505 by Jupiter
On 13 December 1989, Jupiter occulted a star with visual magnitude 8.7and an estimated K magnitude of 7. We observed the event from Kitt Peak,Arizona, using a 64 x 64 infrared camera at a wavelength of 2.16microns. The resulting data on refractive defocusing of the stellarsignal give information on the temperature of the jovian atmosphere atpressures approximately 2 to 10 microbar, at near-equatorial latitudes.These are the first new stellar-occulation data for the high jovianatmosphere since the widely observed occulation of beta Sco A and C in1971. Because of improvements in instrumental capability, our data arecomparable to the best beta Sco A data though the star is six magnitudesfainter. We derive a mean atmospheric temperature of 176 +/- 12 K on alevel surface corresponding to an equatorial radius of 71,880 km and apressure of 1.8 microbar at a jovi- centric latitude of 8 deg. Thisresult complements the beta Sco results by providing improved precisionat low jovicentric latitudes where the fainter star beta Sco C was usedin 1971.
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