Rotating Stellar Models Can Account for the Extended Main-sequence Turnoffs in Intermediate-age Clusters
Article
Article Title | Rotating Stellar Models Can Account for the Extended Main-sequence Turnoffs in Intermediate-age Clusters |
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ERA Journal ID | 1057 |
Article Category | Article |
Authors | Brandt, Timothy D. (Author) and Huang, Chelsea X. (Author) |
Journal Title | The Astrophysical Journal: an international review of astronomy and astronomical physics |
Journal Citation | 807 (1), pp. 1-7 |
Article Number | 25 |
Number of Pages | 7 |
Year | 2015 |
Publisher | IOP Publishing |
Place of Publication | United States |
ISSN | 0004-637X |
1538-4357 | |
Digital Object Identifier (DOI) | https://doi.org/10.1088/0004-637x/807/1/25 |
Web Address (URL) | https://iopscience.iop.org/article/10.1088/0004-637X/807/1/25 |
Abstract | We show that the extended main-sequence turnoffs seen in intermediate-age Large Magellanic Cloud (LMC) clusters, often attributed to age spreads of several 100 Myr, may be easily accounted for by variable stellar rotation in a coeval population. We compute synthetic photometry for grids of rotating stellar evolution models and interpolate them to produce isochrones at a variety of rotation rates and orientations. An extended main-sequence turnoff naturally appears in color-magnitude diagrams at ages just under 1 Gyr, peaks in extent between ∼1 and 1.5 Gyr, and gradually disappears by around 2 Gyr in age. We then fit our interpolated isochrones by eye to four LMC clusters with very extended main-sequence turnoffs: NGC 1783, 1806, 1846, and 1987. In each case, stellar populations with a single age and metallicity can comfortably account for the observed extent of the turnoff region. The new stellar models predict almost no correlation of turnoff color with rotational v{sin}i. The red part of the turnoff is populated by a combination of slow rotators and edge-on rapid rotators, while the blue part contains rapid rotators at lower inclinations. |
Keywords | galaxies: clusters: general; galaxies: clusters: individual (NGC 1783, NGC 1806, NGC 1846, NGC 1987); Hertzsprung-Russell and C-M diagrams; Magellanic Clouds; Astrophysics - Solar and Stellar Astrophysics; Astrophysics - Astrophysics of Galaxies |
Contains Sensitive Content | Does not contain sensitive content |
ANZSRC Field of Research 2020 | 510109. Stellar astronomy and planetary systems |
Public Notes | For access to this article, please click on the URL link provided. |
Byline Affiliations | Princeton University, United States |
Institution of Origin | University of Southern Queensland |
https://research.usq.edu.au/item/q726x/rotating-stellar-models-can-account-for-the-extended-main-sequence-turnoffs-in-intermediate-age-clusters
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