Brown Dwarfs, White Dwarfs and Planetary Disks in an Ancient Stellar System
Abstract
Globular clusters are the oldest assemblages of stars in our Galaxy. Their roughly coeval populations, sharing the same composition and distance from Earth, are ideal laboratories to test out theories of stellar evolution. We here propose to observe the globular cluster 47 Tucanae, one of the richest and most carefully observed clusters in our Galaxy, to observe for the first time the cooling brown dwarf sequence and to hunt for ancient planetary systems around white dwarfs. A sample of brown dwarfs that are well characterized in age, distance and metal content will help break the degeneracies that plague current brown dwarf observations and will provide an important test sample for theoretical models of these objects. Additionally, the location of the brown dwarf sequence in the JWST CMD presents a new method for estimating the age of the cluster itself. With the same observations, we will have a large sample of hot white dwarfs, between 9,500~K and 25,000~K, of which about 5% are expected to show the presence of a debris disk if the population is similar to that of the field. On the other hand, observing the faint end of the white dwarf cooling sequence in the infrared will lead to a better understanding of atmospheric properties and systematic issues in our current models.
- Publication:
-
JWST Proposal. Cycle 1
- Pub Date:
- March 2021
- Bibcode:
- 2021jwst.prop.2559C