Examples of spectra showing two emission peaks at different velocities that are not due to self-absorption, in Cha I (a) and in Cha III (b). a) Cha1-C7 and Cha1-C52 have two velocity components in C¹⁸O 2−1 (black) and in the optically thin C¹⁷O 2−1 and C³⁴S 2−1 (red), respectively. Cha1-C15 (dashed) and Cha1-C12 (dotted) are located on either side of Cha1-C7 (see Fig. 2a). They both have only one emission peak that roughly coincides with either the lower velocity or the higher velocity peak of Cha1-C7. b) Cha3-C11 and Cha3-C21 have two velocity components in ¹³CO 2−1 (black) and in the optically thin C¹⁸O 2−1 (red), as well as in CS 2−1 for Cha3-C11.