Spectroscopic detection of multiple populations in the ∼2 Gyr old cluster Hodge 6 in the LMC
Abstract
We report the spectroscopic discovery of abundance spreads (i.e. multiple populations) in the ∼2 Gyr old cluster in the LMC, Hodge 6. We use low-resolution VLT FORS2 spectra of 15 member stars in the cluster to measure their CN and CH band strengths at ≃3883 and 4300 Å, respectively, as well as [C/Fe] and [N/Fe] abundances. We find a subpopulation of two stars that are enriched in nitrogen, and we conclude that this subpopulation is evidence of multiple populations in Hodge 6. This is the second ∼2 Gyr old cluster (the first being NGC 1978 in the LMC) to show multiple populations and the first spectroscopic detection of MPs in a cluster of this age. This result is interesting as it hints at a possible relationship between the disappearance of extended main sequence turn-offs in clusters younger than ∼2 Gyr and the onset of multiple populations at ∼2 Gyr, which should be explored further.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 2019
- DOI:
- 10.1093/mnras/stz317
- arXiv:
- arXiv:1902.02297
- Bibcode:
- 2019MNRAS.484.4718H
- Keywords:
-
- Magellanic Clouds;
- galaxies: star clusters: individual: Hodge 6;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 10 pages, accepted for publication in MNRAS