Detalles de publicación
PP 07034
The ACS Survey of Galactic Globular Clusters. III. The Double Subgiant Branch of NGC 1851
(1) Universita di Padova, (2) Space Telescope Science Institute, (3) Rice University, (4) University of Florida, (6) Dartmouth College, (7) IAC, (8) University of Virginia, (9) University of Texas
Photometry with HST’s ACS reveals that the subgiant branch (SGB) of the
globular cluster NGC 1851 splits into two well-defined branches. If the split is
due only to an age effect, the two SGBs would imply two star formation episodes
separated by ? 1 Gyr. We discuss other anomalies in NGC 1851 which could
be interpreted in terms of a double stellar population. Finally, we compare the
case of NGC 1851 with the other two globulars known to host multiple stellar
populations, and show that all three clusters differ in several important respects.
globular cluster NGC 1851 splits into two well-defined branches. If the split is
due only to an age effect, the two SGBs would imply two star formation episodes
separated by ? 1 Gyr. We discuss other anomalies in NGC 1851 which could
be interpreted in terms of a double stellar population. Finally, we compare the
case of NGC 1851 with the other two globulars known to host multiple stellar
populations, and show that all three clusters differ in several important respects.