Summary: | Data collected in H and K bands from Gemini North observatory using
the NIRI/ALTAIR adaptive optics (AO) system, have been used to draw a
number of new conclusions about the globular cit ster M71. K band obser
vations were made in 2 epochs, separated by a 1.81 year baseline, allowing
for the separation of field stars from cluster stars based on proper motion.
A color-magnitude diagram (CMD) made using only cluster stars agrees
well with current models. A stellar density profile was also constructed and
appears to flatten at small radii, suggesting that a multimass King profile
does describe the cluster quite accurately, a result contrary to that found in
other work. Most significantly, the distance to M71 was calculated using the
measured velocity dispersion compared to the radial dispersion measured for
giant stars. The distance measured was 3.36 ± 0.71 kpc.
|