Star formation in the most extreme environments of the Milky Way with JWST: the case of Westerlund 1
Abstract
JWST has opened the window to the study of the most massive clusters in the Milky Way, venturing into a mass regime previously unexplored: the brown dwarf domain. These clusters, also known as supermassive star clusters, were far more common in the early Universe, but they are rare in our Galaxy and are typically located at prohibitively large distances for the ground-based instrumentation (>4 kpc). One of such regions is Westerlund 1, located at a distance of 4 kpc and with an estimated mass of 52000 Msun, it is the closest supermassive star cluster to the Sun and possibly the most massive cluster in the Milky Way. The environment of Westerlund 1 is far more extreme than that found in nearby regions in terms of both the stellar density and UV energetic field, which is caused by the presence of a rich population of massive stars. Theories of brown dwarf formation suggest that high gas or stellar densities, as well as the presence of massive OB stars, may stimulate the formation of brown dwarfs compared to stars. Furthermore, the timescale of the dispersion of protoplanetary disks, and therefore the formation of planets, may also be severely affected in these environments.
We have recently obtained deep JWST/NIRCAM and MIRI observations of Westerlund 1 within the EWOCS (Extended Westerlund 1 and 2 Open Clusters Survey) project. These observations are targeted to provide for the first time constraints on the formation of brown dwarfs, and the dispersion of protoplanetary disks in such an extreme environment. In this contribution, I will present the NIRCAM and MIRI images and the first results on the (sub)stellar initial mass function of the cluster as well as the presence of protoplanetary disks.
- Publication:
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EAS2024, European Astronomical Society Annual Meeting
- Pub Date:
- July 2024
- Bibcode:
- 2024eas..conf..544A