The Gaia-ESO Survey: pre-main-sequence stars in the young open cluster NGC 3293

A. J. Delgado, J. Sampedro, E. J. Alfaro, M. T. Costado, J. L. Yun, A. Frasca, A. C. Lanzafame, J. E. Drew, J. Eislöffel, R. Blomme, T. Morel, A. Lobel, T. Semaan, S. Randich, R. D. Jeffries, G. Micela, A. Vallenari, V. M. Kalari, G. Gilmore, E. Flaccomio, G. Carraro, C. Lardo, L. Monaco, L. Prisinzano, S. G. Sousa, L. Morbidelli, J. Lewis, S. Koposov, A. Hourihane, C. Worley, A. Casey, E. Franciosini, G. G. Sacco, L. Magrini

Abstract
The young open cluster NGC3293 is included in the observing program of the Gaia-ESO survey (GES). The radial velocity values provided have been used to assign cluster membership probabilities by means of a single-variable parametric analysis. These membership probabilities are compared to the results of the photometric membership assignment of NGC3293, based on UBVRI photometry. The agreement of the photometric and kinematic member samples amounts to 65 per cent, and could increase to 70 per cent as suggested by the analysis of the differences between both samples. A number of photometric PMS candidate members of spectral type F are found, which are confirmed by the results from VPHAS photometry and SED fitting for the stars in common with VPHAS and GES data sets. Excesses at mid- and near-infrared wavelengths, and signs of Hα emission, are investigated for them. Marginal presence of Hα emission or infilling is detected for the candidate members. Several of them exhibit moderate signs of U excess and weak excesses at mid-IR wavelengths. We suggest that these features originate from accretion discs in their last stages of evolution.

Keywords
stars: pre-main-sequence, open clusters and associations: general, open clusters and associations: individual: NGC 3293

Monthly Notices of the Royal Astronomical Society
Volume 460, Page 3305
May 2016

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