Problem set 3 for ASTR 221: Stars and Planets

Due in class Thursday Sept 25

(1)(a) Assume that a spherical dust grain located 1AU from the Sun has a radius of 0.1 micron and a density of 3 g/cm**3. In the absence of gravity, estimate the acceleration of that grain due to radiation pressure. Assume that the solar radiation is completely absorbed.
(b) What is the gravitational acceleration on the grain?

(2) Comet 1943I, which last passed through perihelion on Feb 27, 1991, has an orbital period of 512 years and an orbital eccentricity of 0.999914 (!). This is one of a class of so-called sun-grazing comets.
(a) What is the comet's semi-major axis?
(b) Determine its perihelion and aphelion distances from the Sun.
(c) What is the most likely source of this object, the Oort Cloud or the Kuiper belt?
Carroll and Ostlie (on reserve in the library) p 29, 30 may be useful here.

Kutner P26.1, P26.6 (remember, Problems, not Questions!)