The CFHT Open Cluster Survey : NGC 2099

Embargoed until 10:00 EDT  June 5, 2000

These images were presented at the American Astronomical Society meeting in Rochester, NY  on June 5, 2000.

Figure 1 :  True-color portrait of the rich open star cluster NGC 2099, located at about 5000 light-years from the Sun, and containing over 2000 stellar members.  The images were taken with the CFH12K mosaic camera at the Canada-France-Hawaii Telescope.  The field size is roughly 1/2 degree top to bottom, and almost 3/4 degrees left-to-right.

PHOTO CREDIT : Harvey Richer, Patrick Durrell, Gregory Fahlman, Jason Kalirai, Francesca D'Antona, Gianni Marconi -- Images obtained at the Canada-France-Hawaii Telescope

Figure 2 : Image of the CFH12K mosaic CCD camera at the Canada-France-Hawaii Telescope.  This mosaic camera is the largest such array available for astronomy in the world, and contains 100 million picture elements.  The field size of the camera is so large that the Full Moon could easily be imaged with it.

PHOTO CREDIT : The  Canada-France-Hawaii Telescope Corporation

NGC 2099 color-magnitude diagram

Figure 3 : This diagram (called a color-magnitude diagram, or CMD)  shows the brightnesses of the stars in NGC 2099 plotted against their colors.  The left-hand panel shows the existing data obtained with photographic plates in 1967 by West while the right-hand plot exhibits the new data just recently obtained with the large mosaic imager on the Canada-France-Hawaii Telescope.  The stars belonging to the cluster are those lying along the thin sequence in the upper part of the figure.  The remaining stars are those in the disk of the Milky Way and are unrelated to the cluster.  These data yield the cluster age (250 million years), its distance (5000 light-years), and a few stellar corpses (white dwarfs) located  in the lower left section of the diagram.  This is the first time that such dead stars have been seen in this cluster.

PHOTO CREDIT : The University of British Columbia and the Canada-France-Hawaii Telescope Corporation

For more information, contact :

  Dr. Harvey Richer  (UBC)    604-822-4134          email :
  Dr. Patrick Durrell  (UBC)    604-822-5564          email :
  Dr. Gregory Fahlman (CFHT)   808-885-7944   email :