M15: Dense Globular Star Cluster
Life might get dull
at the core of M15 but the
sky would always be
bright with stars!
In fact, only 40,000 light-years away in the constellation Pegasus, M15
is one of the most densely packed
globular star clusters
in our Milky Way Galaxy.
This stunning Hubble Space Telescope
image
of M15 shows
thousands of individual stars across the
central 10 or so light-years of the cluster,
also cataloged as NGC 7078.
Yet even the Hubble's sharp
vision
can't clearly separate the stars
at this cluster's
core.
Globular star clusters harbor
from a hundred thousand up to a million stars and roam
the
Milky Way halo.
Like most globulars,
M15 is filled with ancient stars, about 12 billion
years old compared to the Sun's estimated 4.5 billion years.
Its cool red giant stars appear yellowish in this color composite image.
Unlike most globulars, M15 displays
a planetary
nebula, the briefly
visible gaseous shroud of a dying star.
Can you pick it out?
Cataloged as Kuestner 648,
M15's planetary nebula is the
round pinkish cloud at the upper left.