The James Webb Space Telescope (JWST) has captured a new, vibrant image of the Westerlund 2 star cluster, revealing intricate details of a stellar nursery located 20,000 light-years from Earth in the constellation Carina. This cluster resides within the star-forming nebula Gum 29.
Westerlund 2 is a compact cluster, measuring between 6 and 13 light-years in diameter, and hosts approximately 3,000 stars. At an estimated age of 2 million years, it contains some of the galaxy's hottest, brightest, and most massive stars. A decade ago, the Hubble Space Telescope also observed Westerlund 2, providing a view in visible and near-infrared light.
The latest JWST portrait combines infrared data from the telescope's Near-Infrared Camera and Mid-Infrared Instrument. This advanced imagery highlights young, massive stars, along with the surrounding clouds and walls of dust sculpted by their intense light. The scene also shows wisps of orange and red gas, and blue and pink material drifting off, alongside tiny stars still embedded in their formation clouds.
The star cluster is characterized by a continuous cycle of star formation, where young stars emit intense radiation, heating the nebula and triggering the birth of new stars.
Crucially, the new JWST observations, taken across various infrared wavelengths, included bands sensitive to methane and polycyclic aromatic hydrocarbon (PAH) emission. This allowed astronomers to identify a population of brown dwarfs, often called 'failed stars,' some with masses only about 10 times that of Jupiter. Brown dwarfs are objects with masses between typical stars and planets (10 to 90 times Jupiter's mass) that lack sufficient mass to initiate nuclear fusion in their cores.
These new observations are expected to provide valuable insights into the different stages of a star's life and the mechanics of planet-forming disks around massive stars.