Young stars in Dragonfish

We derived the physical properties for some of these from their spectral energy distributions (SEDs). For the cloud images and YSOs, the three-dimensional fractal dimension (Df) was calculated using previously developed and calibrated algorithms. The fractal dimension of the Dragonfish Nebula (Df=2.6-2.7) agrees very well with values previously obtained for the Orion, Ophiuchus, and Perseus clouds.

On the other hand, YSOs exhibit on average a significantly smaller value (Df=1.9-2.0) that indicates a much more clumpy structure than the material from which they formed. This is a clear and direct evidence that the clustering degree of the newly born stars is significantly higher than that of the parent cloud from which they formed, but the physical mechanism behind this behaviour is still not clear. Additionally, younger Class I and Class II sources have smaller values (Df=1.7+/-0.1) than more evolved Transition Disk objects (Df=2.2+/-0.1), evidencing a certain evolutionary effect where an initially clumpy structure tends to gradually disappear over time.

The structure of the Dragonfish complex is similar to that of other molecular clouds in the Galaxy. However, we found clear and direct evidence that the clustering degree of the newly born stars is significantly higher than that of the parent cloud from which they formed. The physical mechanism behind this behaviour is still not clear.