A new component of cosmic rays?

Recent direct measurements of the energy spectra of the major mass components of cosmic rays have indicated the presence of a 'kink' in the region of 200 GeV per nucleon. The kink, which varies in magnitude from one element to another, is much sharper than predicted by our cosmic ray origin model in which supernova remnants are responsible for cosmic ray acceleration and it appears as though a new, steeper component is responsible. The component amounts to about 20 percent of the total at 30 GeV/nucleon for protons and helium nuclei and its magnitude varies with nuclear charge; the unweighted fraction for all cosmic rays being 36%. The origin of the new component is subject to doubt but the contenders include O, B. A, supergiant and Wolf-Rayet stars, by way of their intense stellar winds. Another explanation is also in terms of these particles as the sources but then being trapped, and even further accelerated, in the Local Bubble. (C) 2011 Elsevier B.V. All rights reserved.