Colour-magnitude diagrams of star forming regions
I am interested in using observations of large samples of young stars to
understand planet and star formation.
The primary tool I am using is the colour-magnitude diagram, and
comparing such diagrams from many different associations is proving
to be a powerful diagnostic of the underlying physics.
For example, there is currently a hot debate as to whether star
formation is a slow (~10 million years) or a rapid (~1 million year) process.
The colour-magnitude diagrams indicate it is a slow process, as the
stars in a given association seem to have a large range of ages.
However, this spread could have other explanations, and we have
investigated whether mis-identification of members or binarism and
short term (~1 year) variability can explain the spread (
Burningham et al 2005b
The short answer is the apparent spreads in colour-magnitude space are
not caused by any of these processes, and so we are now investigating
the effects of longer term differences in accretion rate.
We have already found stars that can change their accretion rate
drastically on timescales of ~10 years
(Littlefair et al 2004
but are also investigating using rotation rate as an
(Littlefair et al 2005