Download Lecture 23: Jovian Planets II - Lecture Notes | ASTR 105G and more Study notes Astronomy in PDF only on Docsity! Lecture 23 Jovian Planets II ASTR 105G: The Planets November 18, 2008 Announcements 1. HOMEWORK 10 DUE TODAY Last time ... • We talked about general characteristics of Jovian planets • Mostly H, He, and hydrogen compounds • They rotate fast • Jupiter has H gas, liquid H, metallic H, and rocky core 1 Jovian Atmospheres 1.1 Jupiter Jupiter - Composition • Jupiter’s interior is mostly H and He, but it has different layers or zones • These are distinguished by different phases of the hydrogen • Its “crust” is gaseous H because it’s cold and not dense (125K) • Below the crust it is warmer, 2000K, and is liquid H • Its “mantle” is hot and dense, and the H is metallic (solid) - conducting • The core is very hot and dense and we have rock, metals, H compounds • Cutaway of Jupiter’s interior1 Internal Heating • Jupiter has a lot of internal heat but loses a small fraction because it is so big • Accretion, differentiation, and radioactive decay are not enough to explain its large heat reserves • It heats up by contracting (2 cm/year) • Convert gravitational potential energy to thermal energy 1http://en.wikipedia.org/wiki/Image:Jupiter interior.png Lecture 23 November 18, 2008 2 / 6 Figure 1: Stratification of Jupiter’s atmosphere. Weather • Remember, next to H and He, C, O, and N are the most common elements, that’s why atmospheres typically have compounds like CH4, NH3, and H2O • Atmosphere is somewhat similar to Earth’s temperature stratification • Gases rise by convection and condense into clouds in 3 layers in the troposphere: – Lowest layer (cooler): water droplets – Then ammonium hydrosulfide – Top layer: ammonia Jupiter’s Atmosphere Source of Figure 1: http://www.britannica.com/EBchecked/topic-art/308403/71526/Profile-of-Jupiters-atmosphere- as-deduced-from-accelerometer-data-and Storms • Fast rotation and Coriolis effect creates many cells or bands of circulating air
