Abstract We have observed the three low-mass protostars, IRAS 15398−3359, L1527 IRS, and TMC-1A, with ALMA 12 m array, ACA 7 IRAM-30 APEX telescopes in C 18 O J = 2–1 emission. Overall, emission shows clear velocity gradients at radii of ∼100–1000 au, which likely originate from rotation envelopes, while are less structures more perturbed on scales ∼1000–10,000 au. 15398−3359 IRS show a break ∼...
