Structure of the Atmosphere of Jupiter: Galileo Probe Measurements

• Published in: Science (American Association for the Advancement of Science) Vol. 272; no. 5263; pp. 844 - 845
• Main Authors: Seiff, Alvin, Kirk, Donn B., Tony C. D. Knight, Mihalov, John D., Blanchard, Robert C., Young, Richard E., Schubert, Gerald, von Zahn, Ulf, Lehmacher, Gerald, Milos, Frank S., Wang, Jerry
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 10.05.1996; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: Aerospace Education; Altitude; Astronomical and space-research instrumentation; Astronomy; Atmosphere; Atmospherics; Climate; Earth, ocean, space; Exact sciences and technology; Fractions; Fundamental astronomy and astrophysics. Instrumentation, techniques, and astronomical observations; Galileo Probes Jupiter's Atmosphere; Heat; Jovian atmosphere; Jupiter; Jupiter (Planet); Jupiter probes; Lapse rate; Lunar, planetary, and deep-space probes; Measurement; Motion; Neutral atmospheres; Observation; Observations; Occultation; Parachutes; Planetary atmospheres; Planetary, asteroid, and satellite characteristics and properties; Planets; Planets, their satellites and rings. Asteroids; Pressure; Pressure sensors; Scientific Concepts; Sensors; Solar system; Space flight; Space probes; Temperature; Water; Planetary atmospheres; Pressure distribution; Temperature distribution; Galileo space probes; Jupiter planet
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.272.5263.844

Temperatures and pressures measured by the Galileo probe during parachute descent into Jupiter's atmosphere essentially followed the dry adiabat between 0.41 and 24 bars, consistent with the absence of a deep water cloud and with the low water content found by the mass spectrometer. From 5 to 15 bars, lapse rates were slightly stable relative to the adiabat calculated for the observed H$_2$/He ratio, which suggests that upward heat transport in that range is not attributable to simple radial convection. In the upper atmosphere, temperatures of >1000 kelvin at the 0.01-microbar level confirmed the hot exosphere that had been inferred from Voyager occultations. The thermal gradient increased sharply to 5 kelvin per kilometer at a reconstructed altitude of 350 kilometers, as was recently predicted. Densities at 1000 kilometers were 100 times those in the preencounter engineering model.