Asymmetric silicate dust distribution toward the silicate carbon star BM Geminorum K. Ohnaka, H. Izumiura, Ch. Leinert, T. Driebe, G. Weigelt and M. Wittkowski A&A, 490 1 (2008) 173-178 Published online: 25 August 2008 DOI: 10.1051/0004-6361:200810229