Thompson, Simon

Contact Email: sat@astro.keele.ac.uk
Institute: Keele University
Keele Staffordshire UK ST5 5BG
First Coauthor: Rob Jeffries
Institute: Keele University
Second Coauthor: Tim Naylor
Institute: Exeter University
Presenting Thesis: Yes
Subject Area: Star Clusters, Associations
Waveband: Optical
Technique: Photometry
Presentation: Poster Display
Title: A deep optical and infra-red survey of Cepheus OB3b
Abstract: Our initial analysis suggests a surprising dearth of stars below the hydrogen burning threshold in the young unbound stellar association, Cepheus OB3b. Evidence has been collected from two deep surveys of the area, covering 1.12 square degrees in the optical (RIZ) bands, and 0.13 square degrees in the near infra-red (JHK). Limiting magnitudes are $R\sim24.5$, $I\sim23.5$, $J\sim20.0$, $H\sim19.0$, $K\sim18.0$. Suspected cluster members have been selected initially from an I v I-Z colour magnitude diagram, then cross-referenced and confirmed in the corresponding I v R-I diagram. By matching the positions of these sources with the corresponding NIR counterparts, we have completed a catalogue of optical and NIR magnitudes for candidate members of the association. Following individual de-reddening of these stars, masses have been derived using a Baraffe98 model isochrone. Conclusions are complicated by both differential reddening and an apparent age spread.