Extremely red stellar objects revealed by IPHAS
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Author
Wright, Nick
Greimel, R.
Barlow, M.J.
Drew, J.E.
Cioni, M-R.L.
Zijlstra, A.A.
Corradi, R.L.M.
Gonzalez-Solares, E.
Groot, P.
Irwin, J.
Irwin, M.J.
Mampaso, A.
Morris, R.A.H.
Steeghs, D.
Unruh, Y.C.
Walton, N.A.
Attention
2299/3318
Abstract
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 Survey (IPHAS) of the northern galactic plane. The vast majority of these objects have no previous identification. Analysis of optical, near- and midinfrared 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 filter used for IPHAS observations.