Cadelano, M, Dalessandro, E, Salaris, M, Bastian, N, Mucciarelli, A, Saracino, S, Martocchia, S and Cabrera-Ziri, I (2021) Expanding the Time Domain of Multiple Populations: Evidence of Nitrogen Variations in the similar to 1.5 Gyr Old Star Cluster NGC 1783. ASTROPHYSICAL JOURNAL LETTERS, 924 (1). ISSN 2041-8205

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Abstract

We present the result of a detailed analysis of Hubble Space Telescope UV and optical deep images of the massive and young (∼1.5 Gyr) stellar cluster NGC 1783 in the Large Magellanic Cloud. This system does not show evidence of multiple populations (MPs) along the red giant branch (RGB) stars. However, we find that the cluster main sequence (MS) shows evidence of a significant broadening (50% larger than what is expected from photometric errors) along with hints of possible bimodality in the MP sensitive (mF343N − mF438W, mF438W) color–magnitude diagram (CMD). Such an effect is observed in all color combinations including the mF343N filter, while it is not found in the optical CMDs. This observational evidence suggests we might have found light-element chemical abundance variations along the MS of NGC 1783, which represents the first detection of MPs in a system younger than 2 Gyr. A comparison with isochrones including MP-like abundances shows that the observed broadening is compatible with a N abundance enhancement of Δ([N/Fe]) ∼ 0.3. Our analysis also confirms previous results about the lack of MPs along the cluster RGB. However, we find that the apparent disagreement between the results found on the MS and the RGB is compatible with the mixing effects linked to the first dredge up. This study provides new key information about the MP phenomenon and suggests that star clusters form in a similar way at any cosmic age.

Item Type:	Article
Uncontrolled Keywords:	ABUNDANCE PATTERNS; AGE; ANOMALIES; Astronomy & Astrophysics; GLOBULAR-CLUSTERS; HIGH-REDSHIFT; MAGELLANIC-CLOUD; NO EVIDENCE; Physical Sciences; ROTATION; Science & Technology; STELLAR POPULATIONS; SUPERMASSIVE STARS; Science & Technology; Physical Sciences; Astronomy & Astrophysics; GLOBULAR-CLUSTERS; STELLAR POPULATIONS; ABUNDANCE PATTERNS; SUPERMASSIVE STARS; MAGELLANIC-CLOUD; HIGH-REDSHIFT; NO EVIDENCE; AGE; ANOMALIES; ROTATION; Astronomy & Astrophysics; 0201 Astronomical and Space Sciences
Subjects:	Q Science > QB Astronomy
Divisions:	Astrophysics Research Institute
Publisher:	IOP PUBLISHING LTD
SWORD Depositor:	A Symplectic
Date Deposited:	12 Oct 2022 09:49
Last Modified:	12 Oct 2022 10:00
DOI or ID number:	10.3847/2041-8213/ac424a
URI:	https://researchonline.ljmu.ac.uk/id/eprint/17821

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