I looked on the maps, and then went to wikipedia, and yes, it is that
one. I recognised it from a photo, have been looking at it for years.
They said "The cluster core radius is about 8
light years and
tidal radius is about 43 light years. The cluster contains over 1,000 statistically confirmed members, although this figure excludes unresolved
binary stars.
[18] It is dominated by young, hot
blue stars, up to 14 of which can be seen with the naked eye depending on local observing conditions. The arrangement of the brightest stars is somewhat similar to
Ursa Major and
Ursa Minor. The total mass contained in the cluster is estimated to be about 800
solar masses.
[18]
The cluster contains many
brown dwarfs, which are objects with less than about 8% of the
Sun's mass, not heavy enough for
nuclear fusion reactions to start in their cores and become proper stars. They may constitute up to 25% of the total population of the cluster, although they contribute less than 2% of the total mass.
[19] Astronomers have made great efforts to find and analyse brown dwarfs in the Pleiades and other young clusters, because they are still relatively bright and observable, while brown dwarfs in older clusters have faded and are much more difficult to study".