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.
(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.
Kutner P26.1, P26.6 (remember, Problems, not Questions!)
(b) What is the gravitational acceleration on the grain?
(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.