В повестке семинара:

Tomas Kohout (Institute of Geology, Academy of Sciences of the Czech Republic and Department of Physics, University of Helsinki)

MAGNETIC PROPERTIES OF COMETARY BODIES AND DETECTION LIMITS OF THE ROSETTA SPACE MISSION

Comets are known to contain iron bearing sulfides within dusty fraction. Their surfaces are subject to temperature variations in the range of 100-200 K down to the depth of several meters while the cometary interior is thermally stable at several tens of Kelvin. The review of iron bearing sulfide magnetism shows that while at room temperature most of these sulfides are not significantly magnetic, they became significantly magnetic at temperatures typical for cometary bodies.

Thus not only FeNi metal, but also sulfides have to be considered in the interpretation of magnetic data from cometary objects. ESA (European Space Agency) Rosetta mission (launched in 2004) is equipped with magnetometer and will arrive to comet 67P/Churyumov Gerasimenko in May 2014. It will conduct magnetic observations during the approach the comet to the Sun.

Modeling indicates that magnetic interactions between cometary nucleus containing iron bearing sulfides and interplanetary magnetic field would be weak and difficult, but not impossible, to detect from orbit. Rosetta's Philae lander present on the surface can provide more reliable signal.