Properties of dust in the high-latitude translucent cloud L1780 - I. Spatially distinct dust populations and increased dust emissivity from ISO observations*M. Ridderstad, M. Juvela, K. Lehtinen, D. Lemke and T. LiljeströmA&A, 451 3 (2006) 961-971DOI: https://doi.org/10.1051/0004-6361:20053467