Circumstellar discs in the young sigma Orionis cluster

Abstract

We present new K- and L'-band imaging observations for members of the young (3-5 Myr) sigma Orionis cluster, obtained with UIST at UKIRT. We determine (K-L') colour excesses with respect to the photospheres, finding evidence for warm circumstellar dust around 27 out of 83 cluster members that have masses between 0.04 Msun and 1.0 Msun. This indicates a circumstellar disc frequency of at least (33 +/- 6)% for this cluster, consistent with previous determinations from smaller samples (Oliveira et al. 2004) and also consistent with the 3 Myr disc half-life suggested by Haisch et al. (2001). There is marginal evidence that the disc frequency declines towards lower masses, but the data are also consistent with no mass-dependence at all. There is no evidence for spatial segregation of objects with and without circumstellar discs.

accepted by MNRAS main journal, 10 pages and 5 figures

References in corpus (1)

• Rotation and accretion of very low mass objects in the SigmaOri cluster

Cited by in corpus (11)

• Empirical isochrones and relative ages for young stars, and the radiative-convective gap
• FLAMES spectroscopy of low-mass stars in the young clusters sigma Ori and lambda Ori
• Kinematic structure in the young Sigma Orionis association
• The brightest stars of the sigma Orionis cluster
• Stars and brown dwarfs in the sigma Orionis cluster: the Mayrit catalogue
• Spatial distribution of stars and brown dwarfs in sigma Orionis
• Dynamical parallax of sigma Ori AB: mass, distance and age
• High-Resolution Chandra X-ray Imaging and Spectroscopy of the Sigma Orionis Cluster
• Accretion properties of T Tauri stars in sigma Ori
• Low-resolution spectroscopy and spectral energy distributions of selected sources towards sigma Orionis
• An Infrared Census of Star Formation in the Horsehead Nebula