Transient dust in warm debris disks - Detection of Fe-rich olivine grains J. Olofsson, A. Juhász, Th. Henning, H. Mutschke, A. Tamanai, A. Moór and P. Ábrahám A&A, 542 (2012) A90 Published online: 13 June 2012 DOI: 10.1051/0004-6361/201118735