GALILEO PROBE MEASUREMENTS OF D/H AND 3HE/4HE IN JUPITER's ATMOSPHERE

    loading  Checking for direct PDF access through Ovid

Abstract

The Galileo Probe Mass Spectrometer measurements in the atmosphere of Jupiter give

These ratios supercede earlier results by Niemann et al. (1996) and are based on a reevaluation of the instrument response at high count rates and a more detailed study of the contributions of different species to the mass peak at 3 amu. The D/H ratio is consistent with Voyager and ground based data and recent spectroscopic and solar wind (SW) values obtained from the Infrared Spectroscopic Observatory (ISO) and Ulysses. The 3He/4He ratio is higher than that found in meteoritic gases (1.5 ± 0.3) × 10−4. The Galileo result for D/H when compared with that for hydrogen in the local interstellar medium (1.6 ± 0.12) × 10−5 implies a small decrease in D/H in this part of the universe during the past 4.55 billion years. Thus, it tends to support small values of primordial D/H - in the range of several times 10−5 rather than several times 10−4. These results are also quite consistent with no change in (D+3He)/H during the past 4.55 billion years in this part of our galaxy.

Related Topics

    loading  Loading Related Articles