A new histogram-free likelihood method applied to simulated JWST observations of brown dwarfs shows that globular cluster ages can be determined with formal errors under 0.2 Gyr.
Multiple Stellar Populations in Globular Clusters
6 Pith papers cite this work. Polarity classification is still indexing.
abstract
Globular Clusters (GCs) exhibit star-to-star variations in specific elements (e.g., He, C, N, O, Na, Al) that bare the hallmark of high temperature H burning. These abundance variations can be observed spectroscopically and also photometrically, with the appropriate choice of filters, due to the changing of spectral features within the band pass. This phenomenon is observed in nearly all of the ancient GCs, although, to date, has not been found in any massive cluster younger than 2~Gyr. Many scenarios have been suggested to explain this phenomenon, with most invoking multiple epochs of star-formation within the cluster, however all have failed to reproduce various key observations, in particular when a global view of the GC population is taken. We review the state of current observations, and outline the successes and failures of each of the main proposed models. The traditional idea of using the stellar ejecta from a 1st generation of stars to form a 2nd generation of stars, while conceptually straight forward, has failed to reproduce an increasing number of observational constraints. We conclude that the puzzle of multiple populations remains unsolved, hence alternative theories are needed.
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High-resolution zoom-in simulation of a z~10 galaxy produces over 10^5 star clusters with scale-free mass function, 90% of star formation in clusters, global SFE 0.2-0.3, and reproduces JWST super-bright galaxies via feedback-free bursts.
HST photometry reveals radial color gradients in two ETGs that match predictions from the multiple-population scenario linking the UV upturn to second-generation stars from dissolved globular clusters.
JWST NIRCam survey of 11 globular clusters detects multiple populations in low-mass stars, showing discrete sequences in some clusters and continuous distributions or helium/oxygen variations in others, plus an M-dwarf gap in NGC 104.
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New Way to Date Globular Clusters: Brown Dwarf Cooling Sequences
A new histogram-free likelihood method applied to simulated JWST observations of brown dwarfs shows that globular cluster ages can be determined with formal errors under 0.2 Gyr.