All Figures

$\begin{figure} \par\includegraphics[width=4.7cm,clip]{0220fig1.eps} \end{figure}$ Figure 1: The distribution of specific angular momenta of prestellar cores formed in our simulations using model M6k2 (non-hatched histogram) is compared to the distribution of specific angular momenta of observed molecular cloud cores (hatched distributions). The observational data were taken in a) from Table 5 in Caselli et al. (2002), in b) from Table 2 in Goodman et al. (1993), Table 4 in Barranco & Goodman (1998) and Table A2 in Jijina et al. (1999) and in c) from Table 7 in Pirogov et al. (2003). We take f_j to represent the percentage of the total number of existing cores in a specific angular momentum bin.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0220fig2.eps} \end{figure}$ Figure 2: Distribution of specific angular momenta of the protostars or protostellar systems at different evolutionary phases of the numerical model M6k2 as denoted by the local star formation efficiency in percent, a)- d). We compare in e) with the j-distribution of binaries among nearby G-dwarf stars from Duquennoy & Mayor (1991) (for details see text) and in f) with the distribution of specific angular momenta of binaries in the Taurus star-forming region from Fig. 5 in Simon (1992). Again, f_j represents the normalized distribution function.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=13.5cm,clip]{0220fig3.eps} \end{figure}$ Figure 3: Absolute value of specific angular momentum (solid line) of our model M6k2 as a) a function of mass and as b) a function of time for five different protostellar objects with approximately equal final masses ( $M=0.94~M_{\odot}$ ). In a) the x-component (dotted line), the y-component (dashed line) and the z-component (dashed-dotted line) of the specific angular momenta are shown as well. For comparison the mass accretion rates onto the protostar are indicated in b) by a dashed line (associated y-axis on the right hand side).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0220fig4.eps} \end{figure}$ Figure 4: Absolute values of specific angular momenta (dotted lines) of all protostars (i.e. "sink particles'') from our model M6k2 as a function of mass. The specific angular momenta are averaged at certain mass values which are separated by $0.01~M_{\odot}$ and the resulting points are indicated by crosses. The solid line represents a fit of these averaged specific angular momenta in the mass range between 0 and $1.7~M_{\odot}$ In a) we fit with a function of the form: $j=\mathcal{A} {(M/ M_{\odot})^{2/3}}$ , $\mathcal{A}=(1.3\pm0.6)\times10^{20}~{\rm cm^2~s^{-1}}$ , and in b) we use a square root function: $j=\mathcal{B} \sqrt{M/ M_{\odot}}$ , $\mathcal{B}=(1.3\pm0.6)\times10^{20}~ {\rm cm^2~s^{-1}}$ . One standard deviation is marked by the dashed lines.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=14cm,clip]{0220fig5.eps} \end{figure}$ Figure 5: Distribution of $\beta$ obtained from our model M6k2 with $15 \%$ a), $30 \%$ b), $45 \%$ c) and $60 \%$ d) of the material accreted. For the collapsed protostellar cores in our models (solid lines) we calculate $\beta$ using Eq. (6), where we assume solid-body rotation of a uniform density sphere and take the calculated specific angular momentum j. For the prestellar cores (i.e. Jeans-unstable gas clumps; see the dashed lines) we derive $\beta$ self-consistently from the three-dimensional density and velocity structure, using Eq. (10). For comparison we also indicate with dotted lines the values reported by Goodman et al. (1993, see their Fig. 11) for observed molecular cloud cores. These were obtained with the same assumptions, and we use the same binning with $f_{\beta }$ representing the fraction of objects per $\beta$ bin.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=16cm,clip]{0220fig6.eps} \end{figure}$ Figure 6: Average specific angular momentum of protostellar objects in different turbulent environments as a function of the associated Mach number. Different shapes mark different driving scales k (circle - k=2.0, star - k=4.0, square - k=8.0). GA stands for the Gaussian collapse without driving (arrow pointing downward). Different shades represent different stages of accretion (white - 15% material accreted, gray - 30% material accreted, black - 45% material accreted). In a) all protostars (identified as "sink particle'' in the simulations) were used in calculating the average, in b) through d) only objects in the denoted mass bins were considered. The error bars show the standard deviation of $\langle j\rangle$ . For more clarity the symbols are distributed around the corresponding Mach number $\mathcal{M}$ with ${\Delta \mathcal{M}}/{\mathcal{M}}=5\%$ .
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=15.5cm,clip]{0220fig7.eps} \end{figure}$ Figure 7: The correlation of specific angular momenta of different protostellar cores in model M6k2 with respect to their orientation as a function of distance between the cores. As a measure for the correlation the scalar product of different cores was taken and averaged over cores that exhibit similar distances between each other. High positive values denote co-aligned and high negative values denote anti-aligned angular momenta. The three graphs a)- c) show three different times at which $15 \%$ , $30 \%$ and $45 \%$ of the available material was accreted. The error bars show the standard deviation of the averaged correlations.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=15.5cm,clip]{0220fig8.eps} \end{figure}$ Figure 8: Orientation of the angular momenta (arrows) and spatial distribution of the protostellar cores (diamonds) that formed in model M6k2. We present the projections on the xy, xz and yz-plane. The spatial distributions are compared for three different times at which $15 \%$ a), $30 \%$ b) and $45 \%$ c) of the available material is accreted. The length of the arrows scales with the specific angular momentum of the protostellar core.
Open with DEXTER

In the text