Chromospherically active stars in CoRoT fields

We give an accurate MK classification of all targets, which is valuable information on both the main CoRoT project and additional science programs, by means of cross-correlation with MK standard stars, by using artificial neural networks. The presence or absence of excess H{alpha} emission, determined using spectral subtraction technique, is used to characterize the chromospheric activity level.

In most cases our MK classification agrees with the spectral classification reported in the SIMBAD database; however, there are a few stars that are found to have very different MK classes. Our survey reveals that ~7% of late-type stars in our sample indeed possess a very active chromosphere. The measured H{alpha} excess and the presence of the 6708{AA}, Li line allow us to confirm the membership of 5 targets in the young open cluster NGC 2264.