Specific angular momentum (top panel) and velocity gradient (bottom panel) at different radii traced by the available molecular line data. Small red and blue stars correspond to the H¹³CO⁺ and C¹⁷O ALMA line data presented in this work, respectively. Black five-point stars: NH₃ (1,1) and CS (2–1) line data from Little et al. (1985). Black filled circles: H¹³CN (1–0) and H¹³CO⁺ (1–0) line data from Gibb et al. (2003). Black eight-point star: C¹⁸O (2–1) line data from López-Sepulcre et al. (2009).