Examples of Globular Clusters
We collect here several examples of globular clusters in our galaxy and others.
M80 in Scorpius
The adjacent right figure shows a
Hubble Space Telescope image of the globular cluster M80 in the constellation
Scorpius.
M80,
also known as NGC 6093, is slightly below naked-eye visibility at
apparent magnitude 7.3, and can be found a little
north of the bright red star Antares (the "eye" of the Scorpion).
This globular cluster is at
a distance of 8.4 kpc. It is not far from the center of the galaxy, which
lies about 8 kpc
from the Sun in the direction of Sagittarius, which is next to Scorpius.
M3 in Canes Venatici
The adjacent image shows the globular cluster M3 (also named NGC 5272),
which is about 9.4 kpc away in the
direction of the constellation Canes Venatici.
It contains more than half a million
stars. More variable stars have been identified in it than for any other cluster.
Around
170 RR Lyrae variables alone have been found in this cluster (see the discussion of RR
Lyrae variables in Chapter 21). In this image,
cooler red giant stars appear as yellow, while variable stars and hotter giants appear more blue.
