1997A&A...317..898J

L 1521B is a dense core near B216 in one of the long filaments of the Taurus molecular cloud complex. The core is not associated with any known IR sources and shows no apparent signs of star formation. We have mapped the cloud in ¹³CO(1-0) and C¹⁸O(1-0) using a grid of 1'. This area, altogether some 140 square arc minutes, contains the density maximum as well as some parts of the filament north-west of the cloud centre. At the centre position we derive a column density N(C¹⁸O)=4x10¹⁵cm^–2 and an optical depth of about 1.3 for C¹⁸O. Using a value of r=140pc for the distance we estimate that the total mass contained within a radius of 3' around the density maximum is about 20 solar masses. The visual extinction has been estimated from the C¹⁸O column density and through star counts of two fields observed at 2.2µm. The extinction in the central region is A_V≃20mag. We have also mapped part of the B216 filament about one degree north-west of the centre of L 1521B in C¹⁸O(1-0). This area contains two IRAS point sources which are probably associated with class I protostars.