36th DPS Meeting, 8-12 November 2004
Session 18 Outer Planets
Poster I, Tuesday, November 9, 2004, 4:00-7:00pm, Exhibition Hall 1A

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[18.17] A Behaviour of the Methane-Ammonia Absorption Bands on Jupiter in 2004

V.G. Tejfel, A.M. Karimov (Fessenkov Astrophysical Institute)

New CCD-spectrophotometric observations of Jupiter carried out during March-May 2004 as continuing many years program of the Jupiter's methane-ammonia bands behaviour watch. We used grid spectrograph SGS with 4.3 A/pxl dispersion and CCD-camera ST-7XE, both manufactured by SBIG Company. There were recorded during nine nights more 300 CCD-spectrograms of the central meridian and equator of Jupiter and reference spectra of Ganymed. The profiles and equivalent widths (EW) of four absorption bands centered at 619(CH4), 668(NH3), 725(CH4) and 798 (CH4 +NH3) nm were measured for 145-175 points of S-N and W-E cross sections of Jovian disk as well as the depths (Rv) of bands at 619, 668, 702, 725, 787 and 798 nm . General view of the latitudinal variations of the absorptions is similar with the same for preceding years. The 725 nm band (Rv =0.58) shows a depression about 7-10 percent of Rv in EZ, small variations on temperate latitudes, increasing at 15-30 deg and decreasing at 35-50 deg in both hemispheres. A noticeable growth of absorption is observed near 60 deg latitude, especially in N-hemisphere. Then on higher latitudes the absorption is sharply decreased towards the poles to Rv=0.4 or less. Latitudinal variations of Rv for other bands ( besides polar latitudes) are about the limits +/- 5-10 percent and some more irregular than at 725 nm.

The changes of the equivalent widths along equator are noticeably different for bands 725 nm and 798 nm. EW 798 nm is more then EW 725 nm in the center of disk but decreases steeply towards the limbs. There are no W-E asymmetry in the center-to-limb variations even at 10 deg phase angle.

To reveal longitudinal variations we have calculated averaged means of Rv for latitudes -50 to 50 deg. These variations for all bands are no more than 5 percent. All data are presented as an graphic atlas of the Rv and EW latitudinal and longitudinal distribution and will be used later for next analysis and interpretation.

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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.