This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Spectral information We can measure the visible and infra-red radiation separately with a radiometer. The visual brightness is proportional to A and the cross-sectional area, the infra-red brightness is proportional to (1-A) and the cross-sectional area. Thus by measuring both we can get A and the radius. Neglecting latitude effects the absorbed radiation must equal the emitted: Most materials we will come across will have absorption bands in the visible or near infra-red, so the spectrum of the body (ie the power response as a function of wavelength) tells us something about the material of which it is made. Originally it was only possible to make observations in crude colour bands, so the astronomical "UVB" system of classification was used. Nowadays, however, it is possible to measure spectra with much more precision, virtually, often, to the extent of getting almost continous spting almost continous spectral response curves. With this information, it was possible even before satellite flybys of the Jovian satellites to say that Io,...
View Full Document
This note was uploaded on 12/15/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.
- Fall '10