15 December 2008
Kevin Covey (CfA)
"The Age of B59 and the Pipe Nebula: Implications for the Star Formation Timescale"
The Pipe Nebula is a valuable new laboratory for studying the earliest stages of star
formation. Containing only one small cluster (B59) of ~20 young stars, until recently
the Pipe had escaped detailed scrutiny despite its proximity (~130 pc) and size (~10^4
M_sun). Studies of dense cores in the Pipe (Rathborne et al. 2008, Muench et al. 2007,
Lada et al. 2008) find that thermal pressure provides the dominant source of support
against collapse, with non-thermal support constrained to sub-sonic flows. These cores
are also found to be stable, with minimum ages of 1 million years, suggesting that
they are evolving quasi-staticly. These observations run counter to the more rapid
evolution predicted by star formation theories where turbulence provides the dominant
means of support against collapse.
Understanding the nature of this seeming conflict between observations and theory is
essential to ensuring a proper description of time scale of star formation, and thus
the limit to which stellar populations can be considered co-evol. To shed light on the
age of the dense core population in the Pipe, we have made spectroscopic observations
of the stellar content of B59, the most evolved core in the Pipe. I will describe the
results of this observational program, and its broader implications for the star
formation timescale in the Pipe and beyond.