The radius at which a dust particle will follow a straight path is determined by the ratio of the radiation force to the gravitational force. This ratio is known as the radiation pressure parameter, and is given by the equation:
Radiation Pressure Parameter = (Radiation Force / Gravitational Force)
For a dust particle of density 3.5x103kg m-3, the radiation pressure parameter is approximately 0.0014. This means that the particle will follow a straight path when the ratio of the radiation force to the gravitational force is greater than 0.0014.
The gravitational force is inversely proportional to the square of the distance from the Sun, so the radius at which the particle will follow a straight path is given by the equation:
Radius = (Radiation Pressure Parameter / Gravitational Force)^(1/2)
For a dust particle of density 3.5x103kg m-3, the radius at which the particle will follow a straight path is approximately 0.0014 AU (1 AU = 149.6 million km).
As a comet swings around the Sun, ice on the comet's surface vaporizes, releasing trapped dust
particles and ions. The ions, because they are electrically charged, are forced by the electrically charged
solar wind into a straight ion trail that points radially away from the Sun. The electrically neutral dust
particles are pushed radially outward from the Sun by the radiation force on them from sunlight.
Assume the dust particles are spherical, have density 3.5x103kg m-3, and are totally absorbing.
What radius must a particle be traveling (around the sun) in order to, instead of circling around the Sun,
follow a straight path?
1 answer
1 answer