J. Kauffmann — Page 3

arXiv2004

A "Starless" Core that Isn't: Detection of a Source in the L1014 Dense Core with the Spitzer Space Telescope

We present observations of L1014, a dense core in the Cygnus region previously thought to be starless, but data from the Spitzer Space Telescope shows the presence of an embedded source. We propose a model for this source that includes a cold core, heated by the interstellar radiation field, and a low-luminosity internal source. The low luminosity of the internal source suggests a substellar object. If L1014 is representative, other "starless" cores may turn out to harbor central sources.

astro-ph↗

arXiv2004

Structure and Stability of Prestellar Cores

Following an approach initially outlined by McKee & Holliman, we investigate the structure and stability of dense, starless molecular cloud cores. We model those as spherical clouds in hydrostatic equilibrium and supported against gravity by thermal, turbulent, and magnetic pressure. We determine the gas pressure by solving for thermal equilibrium between heating and cooling, while the turbulent and magnetic pressures are assumed to obey polytropic equations of state. In comparing the models to observed cloud cores we find that the observed peak column densities often exceed the limit for stable equilibria supported by thermal pressure alone, suggesting significant non-thermal pressure if the cores are to be stable. Non-thermal support is also needed to stabilize cores embedded in molecular clouds with high average pressures. Since the observed molecular linewidths of cores suggest that the turbulent pressure is lower than the thermal pressure, magnetic field are likely a dominant pressure component in many such cores.

astro-ph↗