The regulation of angular momentum is one of the key processes for our understanding of stellar evolution .
The rotational evolution of solar-mass stars is mainly determined by the magnetic interaction with their circumstellar disk and angular momentum loss through stellar winds , and In contrast to solar-mass stars , very low mass ( VLM ) objects and brown dwarfs are believed to be fully convective .
This may lead to major differences of rotation and activity , since fully convective objects may not host a solar-type dynamo .

Here , we report on our observational efforts to understand the rotational evolution of VLM objects .
By means of photometric monitoring , we determined 62 rotation periods for targets in three clusters , which form an age sequence from 3 to 125 Myr .
We find that VLM objects rotate faster than their solar-mass siblings in all evolutionary stages .
Their rotational evolution seems to be determined by hydrostatic contraction and exponential angular momentum loss .
The photometric amplitudes of the light curves are much lower than for solar-mass stars .
This may be explained as a consequence of smaller spot coverage , more symmetric spot distributions , or lower contrast between spots and their environment .
Most of these results can be explained with a change of the magnetic field properties with decreasing mass .
VLM objects possibly possess only small-scale , turbulent magnetic fields .