Star Clusters


  1. Students for the Exploration and Development of Space or seds. A great site for all things astro.


  1. ../../astro/astro1/cluster/m2_001_noao.jpg M2, NGC7089 is a Galactic globular cluster in Aquarius.

    This image was made using the Kitt Peak National Observatory 0.9-meter telescope.

    M2 is the 2nd object in the Messier Catalog.

    It is about 15 kpc away and is located almost directly below the south Galactic pole in the Galactic halo.

    M2 is one of the richer denser globular clusters with about 10**5 star and a diameter of about 50 pc.

    It has an overall visual magnitude of 6.3 which makes it just barely unobservable with the unaided eye. But it is a good object for small telescopes and binoculars.

    Like all Galactic globular clusters M2 is very old. Current calculations put the ages of Galactic globular clusters at about 12.5 Gyr (FK-638).

    This age is a lower bound on the age of the observable universe which in the concordance model is 13.7+/-0.2 Gyr (FK-653).

    Credit: Doug Williams, REU Program/NOAO/AURA/NSF.

  2. The Pleiades Cluster in Taurus (or M45) An open star cluster. 6 to 9 members are visible to the naked eye. There are about 500 members known: mostly very faint.
  3. M13: A Globular Cluster in Hercules Contains 10**5 to 10**6 stars. Stars in globular clusters are thought to be about 13 Gyr old. Globular cluster may have been the first star groupings to form after the Big Bang. But no globular cluster stars have zero metallicity and so there must have been an earlier generation of star formation in the Big Bang paradigm