1. Multiple power-law tails in the density and column-density distribution in contracting star-forming clumps.
- Author
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Veltchev, Todor V, Girichidis, Philipp, Marinkova, Lyubov, Donkov, Sava, Stanchev, Orlin, and Klessen, Ralf S
- Subjects
TIDAL forces (Mechanics) ,FORCE density ,ACCRETION disks ,DENSITY ,GRAVITY ,PROTOSTARS - Abstract
We present a numerical study of the evolution of power-law tails (PLTs) in the (column-)density distributions (N -PDF, ρ-PDF) in contracting star-forming clumps in primordial gas, without and with some initial rotational and/or turbulent support. In all considered runs multiple PLTs emerge shortly after the formation of the first protostar. The first PLT (PLT 1) in the ρ-PDF is a stable feature with slope q
1 ≃ −1.3 which corresponds – under the condition of preserved spherical symmetry – to the outer envelope of the protostellar object with density profile ρ ∝ l−2 in the classical Larson–Penston collapse model, where l is the radius. The second PLT (PLT 2) in the ρ-PDF is stable in the pure-infall runs but fluctuates significantly in the runs with initial support against gravity as dozens of protostars form and their mutual tidal forces change the density structure. Its mean slope, 〈 q2 〉 ≃ −2, corresponds to a density profile of ρ ∝ l−3/2 which describes a core in free fall in the classical Larson–Penston collapse model or an attractor solution at scales with dominating protostellar gravity. PLT 1 and PLT 2 in the N -PDFs are generally consistent with the observational data of Galactic low-mass star-forming regions from Herschel data. In the runs with initial support against gravity a third PLT (PLT 3) in the ρ-PDFs appears simultaneously with or after the emergence of PLT 2. It is very shallow, with mean slope of 〈 q3 〉 ≃ −1, and is associated with the formation of thin protostellar accretion discs. [ABSTRACT FROM AUTHOR]- Published
- 2024
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