Resumo

RAGA, A.C. et al. The Properties and Stability of Self-Gravitating, Polytropic Spheres with γ =1 to 1.4 Specific Heat Ratios. Rev. mex. astron. astrofis [online]. 2020, vol.56, n.1, pp.55-62.  Epub 19-Mar-2021. ISSN 0185-1101.  https://doi.org/10.22201/ia.01851101p.2020.56.01.07.

We study self-gravitating, hydrostatic spheres with a polytropic equation of state ECUACION (where γ is the specific heat ratio of the gas), considering structures with γ ≈ 1 as a model for molecular cloud cores with small departures from isothermality. We derive the properties (i.e., mass, radius and center to edge density ratio) as a function of for the maximal stable sphere through an application of \Bonnor's stability criterion". We find that in the γ ≈ 1 = 1 → 4/3 range the mass of the maximal sphere (for a given central temperature) is almost constant, and that its radius and center to edge density ratio are growing functions of . We therefore have maximal stable, self-gravitating spheres with similar masses, but with increasing center to edge density contrasts for increasing departures from isothermality.

Palavras-chave : ISM: clouds; ISM: kinematics and dynamics; stars: formation.