Cool Stars 14 - Submitted Abstract # 48 This version created on 05 October 2006 Cool Stars in the Second XMM-Newton Serendipitous Source Catalogue (2XMM): Time Variability John Pye, University of Leicester Duncan Fyfe, University of Leicester Anja Schroeder, University of Leicester Natalie Webb, Centre d'Etude Spatiale des Rayonnements Toulouse Ian Stewart, University of Manchester A pre-release (2XMMp) of the second XMM-Newton Serendipitous Source Catalogue (2XMM) has recently (July 2006) been made public, with the full release due later in 2006. This comprehensive catalogue of serendipitous X-ray sources from the European Space Agency's (ESA) XMM-Newton observatory has been constructed by the XMM-Newton Survey Science Centre (SSC) on behalf of ESA. The catalogue contains more than 150,000 X-ray source detections which relate to more than 120,000 unique X-ray sources, making it the largest catalogue of astronomical X-ray sources ever produced (see e.g. http://xmmssc-www.star.le.ac.uk/ or http://xmm.esac.esa.int/external/xmm_data_acc/xsa/index.shtml ). The catalogue contains source detections drawn from most of the observations publicly available after ~6.5 years of operations. The total sky area covered is ~400 deg^2. The median flux (in the total photon energy band 0.2 - 12 keV) of the catalogue sources is ~2.4E-14 erg cm^-2 s^-1. X-ray spectra and lightcurves are generated for the brighter objects (~10% of the total catalogue). We will highlight the relevance of 2XMM for cool-star research, focussing on the time-domain aspects. ----------------------------------