Cloud disruption via ionized feedback: tracing pillar dynamics in Vulpecula

Abstract

The major physical processes responsible for shaping and sculpting pillars in the clouds surrounding massive stars (i.e. the ‘Pillars of Creation’) are now being robustly incorporated into models quantifying the ionizing radiation from massive stars. The detailed gas dynamics within these pillars can now be compared with observations. Our goal is to quantify the gas dynamics in a pillar being sculpted by a nearby massive star. To do this, we use the CO, 13CO and C18O J = 1–0 emission towards a pillar in the Vulpecula Rift. These data are a combination of Combined Array for Research in Millimeter-Wave Astronomy and Five College Radio Astronomy Observatory observations providing high-resolution (∼5) imaging of large-scale pillar structures (>100 arcsec). We find that this cold (∼18 K), low-density (8 × 103 cm−3) material is fragmenting on Jeans scales, has very low velocity dispersions (∼0.5 km s−1), and appears to be moving away from the ionizing source. We are able to draw direct comparisons with three models from the literature, and find that those with lower velocity dispersions best fit our data, although the dynamics of any one model do not completely agree with our observations. We do, however, find that our observed pillar exhibits many of the characteristics expected from simulations.