2008/06/11 by Kazunari Iwasaki, Toru Tsuribe
Mathematics · Physics and Astronomy · #Astrophysics and Star Formation Studies #Condensation #Differential Equations and Numerical Methods #Dust and Plasma Wave Phenomena #Isobaric process #Isochoric process #Radiative cooling #Radiative transfer #Thermal #Volume (thermodynamics) #astro-ph #physics.flu-dyn
paper · pdf · doi:10.1111/j.1365-2966.2008.13294.x
Accepted for Monthly Notices of the Royal Astronomical Society: 9 pages, 7 figures
openalex publication_date 2008/06/11 · arxiv created 2008/06/17 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
A new self-similar solution describing the dynamical condensation of a radiative gas is investigated under a plane-parallel geometry. The dynamical condensation is caused by thermal instability. The solution is applicable to generic flow with a net cooling rate per unit volume and time ∝ρ2Tα, where ρ, T and α are the density, temperature and a free parameter, respectively. Given α, a family of self-similar solutions with one parameter η is found in which the central density and pressure evolve as follows: ρ(x= 0, t) ∝ (tc−t)−η/(2−α) and P(x= 0, t) ∝ (tc−t)(1−η)/(1−α), where tc is the epoch at which the central density becomes infinite. For η∼ 0 the solution describes the isochoric mode, whereas for η∼ 1 the solution describes the isobaric mode. The self-similar solutions exist in the range between the two limits; that is, for 0 < η < 1. No self-similar solution is found for α > 1. We compare the obtained self-similar solutions with the results of one-dimensional hydrodynamical simulations. In a converging flow, the results of the numerical simulations agree well with the self-similar solutions in the high-density limit. Our self-similar solutions are applicable to the formation of interstellar clouds (H i clouds and molecular clouds) by thermal instability.