Research output: Contribution to journal › Article › peer-review
- G. Beccari
- M.G. Petr-Gotzens
- H.M.J. Boffin
- M. Romaniello
- D. Fedele
- G. Carraro
- G. De Marchi
- W.J. de Wit
- J. E. Drew
- V. M. Kalari
- Carlo Felice Manara
- Eduardo L. Martin
- S. Mieske
- N. Panagia
- L. Testi
- Jorick S. Vink
- J. R. Walsh
- N. J. Wright
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Original language | English |
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Article number | A22 |
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Number of pages | 8 |
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Journal | Astronomy & Astrophysics |
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Volume | 604 |
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Issue | A&A |
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Early online date | 27 Jul 2017 |
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DOIs | |
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Publication status | E-pub ahead of print - 27 Jul 2017 |
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Abstract
As part of the Accretion Discs in H$\alpha$ with OmegaCAM (ADHOC) survey, we imaged in r, i and H-alpha a region of 12x8 square degrees around the Orion Nebula Cluster. Thanks to the high-quality photometry obtained, we discovered three well-separated pre-main sequences in the color-magnitude diagram. The populations are all concentrated towards the cluster's center. Although several explanations can be invoked to explain these sequences we are left with two competitive, but intriguing, scenarios: a population of unresolved binaries with an exotic mass ratio distribution or three populations with different ages. Independent high-resolution spectroscopy supports the presence of discrete episodes of star formation, each separated by about a million years. The stars from the two putative youngest populations rotate faster than the older ones, in agreement with the evolution of stellar rotation observed in pre-main sequence stars younger than 4 Myr in several star forming regions. Whatever the final explanation, our results prompt for a revised look at the formation mode and early evolution of stars in clusters.
Notes
Reproduced with permission from Astronomy & Astrophysics, © 2017 ESO. Published by EDP Sciences.
ID: 12322690