Data reported in Figure 1 correspond to newly detected C<SUB>2</SUB>O and lines towards: L1544 (panels A, B, C, D, E and F); L1498 (panels G and H); and Elias 18 (panels I and J). Each panel reports the molecule and its transition. The detection reported in panel G (performed with the Noto-32m telescope) was acquired with a lower resolution than that used for the observations reported in the other panels (IRAM-30m telescope). For clarity we give a larger VLSR scale that allows a better evaluation of the baseline. <P />Table 1 and Table 2 in the paper report information on the spectroscopic parameters and telescope used. <P />Further details are given in Section 2 in the paper. <P />Files are given in FITS and ASCII format for each panel. <P />(3 data files).