Topic: Formation and Evolution of Cool Stars and Brown Dwarfs
The presence or otherwise of significant age spreads in star-forming regions is hotly debated. Evidence for the existence of age spreads comes from the wide range of luminosities seen for stars of the same colour, although it has been argued that these are predominantly due to instrumental effects or variability. We present an analysis of the rotation of young stars in four young associations and discover a link between rotation rate and luminosity which cannot be reconciled with the interpretation of luminosity spreads as a spread in stellar ages. Instead, we argue that variable accretion histories for young stars can explain both the luminosity spread, and the link between rotation and luminosity presented here.