Physical effects of gas envelopes with different extension on the collapse of a gas core

Abstract

In this paper we study the gravitational collapse of a molecular hydrogen gas cloud composed of a core plus a gas envelope surrounding the core. We numerically simulate the collapse of four cloud models to take a glimpse to the time evolution of several dynamic variables, such as the angular momentum and the $aem$ ratio, as well as the ratios between the thermal and rotational energies with respect to the potential gravitational energy, denoted as $\alpha$ and $\beta$, respectively, among others. We re-take those models introduced by Arreaga et.al (Astronomy and Astrophysics, {\bf Vol. 509}, (2010), pag. A96.) in the present paper in order to produce different outcomes of the collapsing cloud characterized in terms of the aforementioned dynamical variables. Such characterization was missing in the paper by Arreaga et.al (Astronomy and Astrophysics, {\bf Vol. 509}, (2010), pag. A96.), and here we show that the gas envelope extension effects on the collapsing core can be quantitatively compared.