A Tale of Three Cities: OmegaCAM discovers multiple sequences in the color-magnitude diagram of the Orion Nebula Cluster
| Autor: | Beccari, G., Petr-Gotzens, M. G., Boffin, H. M. J., Romaniello, M., Fedele, D., Carraro, G., De Marchi, G., de Wit, W. -J., Drew, J. E., Kalari, V. M., Manara, C. F., Martin, E. L., Mieske, S., Panagia, N., Testi, L., Vink, J. S., Walsh, J. R., Wright, N. J. |
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| Rok vydání: | 2017 |
| Předmět: | |
| Zdroj: | A&A 604, A22 (2017) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1051/0004-6361/201730432 |
| Popis: | 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. Comment: A&A in print |
| Databáze: | arXiv |
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