High-resolution H13CO+ observations toward the driving source of the HH 1-2 system

We observed the (HCO+)-C-13 J = 1 --> 0 line toward the driving source of the Herbig-Haro object HH 1-2 system using the Berkeley-Illinois-Maryland Association interferometer and the Taeduk Radio Astronomy Observatory telescope. Our map shows a 37 " (0.08 pc) scale elongation around VLA 2 and a bulge around VLA 1. The elongation is nearly perpendicular to the HH 1-2 axis as previously observed in the HCO+ 4 --> 3 line. We suggest that this molecular core is a toroidal structure around a newly formed star. While VLA 1 has been considered the central object of the system, because of its higher brightness, our map shows that VLA 2 is more closely associated with the molecular core.