Deflection of the Local Interstellar Dust Flow by Solar Radiation Pressure
M. Landgraf,
12*
K. Augustsson,
3
E. Grün,
4
B. Å. S. Gustafson
5
Interstellar dust grains intercepted by the dust
detectors on the Ulysses and Galileo spacecrafts at heliocentric
distances from 2 to 4 astronomical units show a deficit of grains with
masses from 1 × 10-17 to 3 × 10-16 kilograms relative to grains intercepted outside 4 astronomical units. To divert grains out of the 2- to 4-astronomical
unit region, the solar radiation pressure must be 1.4 to 1.8 times the
force of solar gravity. These figures are consistent with the optical properties of spherical or elongated grains that consist of
astronomical silicates or organic refractory material. Pure graphite
grains with diameters of 0.2 to 0.4 micrometer experience a solar
radiation pressure force as much as twice the force of solar gravity.
1 NASA Johnson Space Center, Mailcode SN2,
Houston, TX 77058, USA.
2 European Space
Agency (ESA), European Space Operation Center, Robert-Bosch-Strasse 5, 64293 Darmstadt, Germany.
3 Department of Computer
and System Sciences, Royal Institute of Technology and Stockholm
University, Electrum 230, 164 40 Kista, Sweden.
4 Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.
5 Department of Astronomy,
University of Florida, Gainesville, FL 32661, USA.
*
To whom correspondence should be addressed (at ESA). E-mail:
mlandgra{at}esoc.esa.de
