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: Homework # 4 Solutions 1. In this problem, you are asked to calculate the expected extinction from a cool cloud. Assume it is spherical and located at a distance of 100 pc from the Earth. Assume the cloud is isothermal with a temperature of 10 K. Assume it is embedded in a warm diffuse ISM with temperature 10,000 K and a density of 1 cm 3 . Use the Bonnor-Ebert critical spherical configuration to estimate the total cloud mass. What is the mass? (You do not have to solve the differential equations, use the known expression.) For diffuse ISM, p o = 1 . 38 10 12 erg cm 3 . The Bonnor-Ebert critical configuration has p o = 1 . 4 G 3 M 2 parenleftbigg N o kT parenrightbigg 4 , M 5 . 1 M We used = 2 because the cloud is molecular. Assuming the density profile in the cloud has the form of the isothermal singular sphere, compute an expression for the visual extinction as a function of angular distance from the cloud center from stars located behind the cloud as seen from the Earth. You may use the relation between visual extinctionas seen from the Earth....
View Full Document
- Spring '11