Massive clumps in the W3-Main cloud core

We present high‐resolution (30‘;0.3 pc) 12CO(2−1), 13CO(2−1), and C18O(2−1) observations of the 7’×5’ region comprising the W3‐Main molecular cloud core. An analysis of velocity channel‐maps of 13CO optical depth and column density reveals seven major clumps, ranging in mass from 180 M⊙ to 965 M⊙. The total H2 mass of the mapped region is ∼6500 M⊙; 58% of the total mass of the mapped region is contained within these seven major clumps, and 26% within just two clumps, one centered on IRS‐4 and the other 30‘ south of that position. The IRS‐4South clump is coincident with a recently discovered peak in submillimeter (350–800 μm) continuum emission, but appears not to be associated with previously identified IRS or radio continuum sources. IRS‐4South is likely the newest center of massive star formation activity in W3‐Main.