This figure shows a schematic representation of the stars in the center of
the dense globular cluster M30. The stellar density is approximately
one million solar masses per cubic parsec in the central regions.
Colors indicate stellar type: a red dot indicates a red giant branch or
a subgiant star, green dots are horizontal branch
stars, blue represents blue straggler stars and, white dots
represent main sequence
stars. The size of each dot is proportional to the stars brightness, with
the biggest dots corresponding to V magnitude 14 stars and the
faintest dots corresponding to V magnitude 21.5 stars.
The cluster M30 contains a higher proportion of blue straggler stars
in it's center than any other known globular cluster.
The green cross marks the dynamical center of the cluster.
This image was may by processing a set of multi-color exposures from
the WFPC-2 camera of the HST.
Details may be found in the paper:
WFPC-2 Observations of the Globular Cluster M30,
by Yanny, B., Guhathakurta, P., Schneider, D. P., & Bahcall,
J. N. 1994, ApJL, 435, L59.
Back to John Bahcall HST Images
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HST Image of the Stars in the Center of the Dense Globular Cluster M30.