An Empirical Model for Protostellar Collapse

By A. Whitworth, D. Ward-Thompson. 2000

140 citations recorded by the source corpus.

We propose a new analytic model for the initial conditions of protostellar collapse in relatively isolated regions of star formation. The model is nonmagnetic and is based on a Plummer-like radial density profile as its initial condition. It fits: the observed density profiles of prestellar cores and class 0 protostars; recent observations in prestellar cores of roughly constant contraction velocities over a wide range of radii; and the lifetimes and accretion rates derived for class 0 and class I protostars. However, the model is very simple, having in effect only two free parameters, so it should provide a useful framework for interpreting observations of prestellar cores and protostars and for calculations of radiation transport and time-dependent chemistry. As an example, we model the prestellar core L1544.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/358a7c8940d83c23301e9fff1450701558f804e2

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In Astronomy and Astrophysics

Citations in the corpus

Simulating star formation in molecular cloud cores. I. The influence of low levels of turbulence on fragmentation and multiplicity (2003, background): “The accretion rate at very early times is slightly inexcess of the Whitworth & Ward-Thompson (2001) value due to the SPH particles having finite mass.”
The James Clerk Maxwell Telescope Legacy Survey of Nearby Star‐forming Regions in the Gould Belt (2007, background): “Alternatively, if the Class 0 duration is only one-tenth of the Class I duration, as is currently suspected (André et al. 2000), then accretion must start very rapidly and decrease over time (e.g., Whitworth & Ward-Thompson 2001), implying a very different collapse scenario.”
Control of star formation by supersonic turbulence (2000, methodology): “For the collapse of a Plummer-type sphere with specifications such as to fit the protostellar core L1544, the time evolution of Ṁ is illustrated in Figure 3 (see Whitworth & Ward-Thompson 2001).”
Cold Dark Clouds: The Initial Conditions for Star Formation (2007, background): “The logotropic density profile of McLaughlin & Pudritz (1996) is too flat at large radii (r−1) to fit most cores (Bacmann et al. 2000), while the Plummer-like profile (Whitworth & Ward-Thompson 2001) seems asymptotically too steep (r−4).”
Systematic Molecular Differentiation in Starless Cores (2001, background): “(Whitworth & Ward-Thompson 2001 have recently proposed a similar expression, although they require 4, which seems outside the range of our empirically determined values.”
Interpreting Spectral Energy Distributions from Young Stellar Objects. I. A Grid of 200,000 YSO Model SEDs (2006, background): “In the outer regions, magnetic fields, turbulence, and other non-ideal initial conditions could affect the density distributions (Foster & Chevalier 1993; Bacmann et al. 2000; Whitworth & Ward-Thompson 2001; Allen et al. 2003; Goodwin et al. 2004; Galli 2005).”
A “Starless” Core that Isn't: Detection of a Source in the L1014 Dense Core with the Spitzer Space Telescope (2004, methodology): “If we consider accretion rates appropriate for the BE or “Plummer-like” sphere (e.g., 3 × 10−5 M⊙ yr −1) as in Whitworth & Ward-Thompson (2001), the disparity between the predicted and observed luminosity is greatly amplified.”
The initial conditions of isolated star formation — VI. SCUBA mapping of pre-stellar cores (2005, background): “For example, a decreasing accretion rate is obtained when the initial radial density profile is relatively flat in the centre, and steepens towards the edge (Foster & Chevalier 1993; Henriksen, André & Bontemps 1997; Whitworth & Ward-Thompson 2001).”