Extremely red stellar objects revealed by IPHAS
| Autor: | Wright, N. J., Greimel, R., Barlow, M. J., Drew, J. E., Cioni, M. -R. L., Zijlstra, A. A., Corradi, R. L. M., González-Solares, E. A., Groot, P., Irwin, J., Irwin, M. J., Mampaso, A., Morris, R. A. H., Steeghs, D., Unruh, Y. C., Walton, N. |
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| Rok vydání: | 2008 |
| Předmět: | |
| Zdroj: | MNRAS: Vol 390, 2008, Page 929 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1111/j.1365-2966.2008.13851.x |
| Popis: | We present photometric analysis and follow-up spectroscopy for a population of extremely red stellar objects extracted from the point-source catalogue of the INT Photometric H-Alpha Survey (IPHAS) of the northern galactic plane. The vast majority of these objects have no previous identification. Analysis of optical, near- and mid-infrared photometry reveals that they are mostly highly-reddened asymptotic giant branch stars, with significant levels of circumstellar material. We show that the distribution of these objects traces galactic extinction, their highly reddened colours being a product of both interstellar and circumstellar reddening. This is the first time that such a large sample of evolved low-mass stars has been detected in the visual and allows optical counterparts to be associated with sources from recent infrared surveys. Follow-up spectroscopy on some of the most interesting objects in the sample has found significant numbers of S-type stars which can be clearly separated from oxygen-rich objects in the IPHAS colour-colour diagram. We show that this is due to the positions of different molecular bands relative to the narrow-band H-alpha filter used for IPHAS observations. The IPHAS (r' - H-alpha) colour offers a valuable diagnostic for identifying S-type stars. A selection method for identifying S-type stars in the galactic plane is briefly discussed and we estimate that over a thousand new objects of this type may be discovered, potentially doubling the number of known objects in this short but important evolutionary phase. Comment: 18 pages, 20 figures, published in MNRAS. Minor text changes and Figure 17 replaced |
| Databáze: | arXiv |
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