High-resolution spectroscopic observations were taken of 29 extended main-sequence turnoff (eMSTO) stars in the young (similar to 200 Myr) Large Magellanic Cloud (LMC) cluster, NGC 1866, using the Michigan/Magellan Fiber System and MSpec spectrograph on the Magellan-Clay 6.5 m telescope. These spectra reveal the first direct detection of rapidly rotating stars whose presence has only been inferred from photometric studies. The eMSTO stars exhibit Ha emission (indicative of Be-star decretion disks), others have shallow broad H alpha absorption (consistent with rotation. greater than or similar to 150 km s(-1)), or deep Ha core absorption signaling lower rotation velocities (less than or similar to 150 km s(-1)). The spectra appear consistent with two populations of stars-one rapidly rotating, and the other, younger and slowly rotating.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/625815 |
| Date | 23 August 2017 |
| Creators | Dupree, A. K., Dotter, A., Johnson, C. I., Marino, A. F., Milone, A. P., Bailey, J. I., Crane, J. D., Mateo, M., Olszewski, E. W. |
| Contributors | Univ Arizona |
| Publisher | IOP PUBLISHING LTD |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | © 2017. The American Astronomical Society. All rights reserved. |
| Relation | http://stacks.iop.org/2041-8205/846/i=1/a=L1?key=crossref.cd5fd4fe9d11b2401f35a59de98d4756 |
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