Infrared photometry of low-mass stars in Praesepe |
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| Authors: | S T Hodgkin D J Pinfield R F Jameson I A Steele M R Cossburn N C Hambly |
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| Institution: | Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH; APS Division, Department of Pure and Applied Physics, Queen's University, Belfast BT7 1NN; Astrophysics Research Institute, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF; Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ |
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| Abstract: | We present follow-up infrared photometry for a sample of low-mass and very low-mass stars in the Praesepe open cluster. Our sample is selected from two sources: (i) 90 stars selected from the Hambly et al. photometric and proper-motion survey of Praesepe; (ii) 17 stars selected from the CCD imaging survey presented by Pinfield et al. We investigate cluster membership using infrared colour–magnitude and colour–colour diagrams. We find 81 likely and two possible members in the Hambly et al. sample, in line with predictions. Contamination in the Pinfield et al. sample is higher, and we find nine probable cluster members. We investigate the non-grey models of Baraffe et al., which are found to be in good agreement with the data. Multiplicity in Praesepe is also examined, and we find the multiple star fraction to be 0.51 from analysis of the I , I ? K diagram. We investigate individual object masses, and find that the faintest candidate cluster members have masses close to the substellar limit. |
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| Keywords: | techniques: photometric binaries: general stars: low-mass brown dwarfs open clusters and associations: individual: Praesepe infrared: stars |
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