2.1.2 Preliminary Results of the Micrometeoroid Experiment on Board Helios A

E. Grün, J. Kissel, H. Fechtig, P. Gammelin, H.-J. Hoffmann
1976 International Astronomical Union Colloquium  
AbstractFor the first time in situ measurements of interplanetary dust have been performed between 0.3 AU and 1 AU from the sun by the micrometeoroid experiment on board Helios A. The measured particle masses are between 10−15g and 10−8g and their measured speeds are between 2 km/sec and 20 km/sec. Particle impacts are identified by the time-of-flight spectra of the ions released upon impact. 15 large particles (m ≥ 10−12g) were detected from Dec. 15, 1974 to Sept. 5, 1975. They show a strong
more » ... hey show a strong increase of the impact rate (appr. a factor of 10) between 1 AU and 0.3 AU. The directions from which they impacted the sensor are concentrated between the solar direction and the apex direction of the Helios spacecraft.
doi:10.1017/s0252921100051642 fatcat:q3hvx4vpcbbghcbuhn7dweguyy