SDSS J212531.92–010745.9 – the first definite PG 1159 close binary system T. Nagel, S. Schuh, D.-J. Kusterer, T. Stahn, S. D. Hügelmeyer, S. Dreizler, B. T. Gänsicke and M. R. Schreiber A&A, 448 2 (2006) L25-L28 Published online: 24 February 2006 DOI: 10.1051/0004-6361:200600009