A deep multi-band investigation of IC2391

TL;DR

This study conducts a deep multi-wavelength survey of IC2391, uncovering new low-mass and sub-stellar members, and identifying debris disk candidates, thereby enhancing understanding of the cluster's population and disk properties.

Contribution

It provides the first deep optical and infrared survey of IC2391, discovering 29 new low-mass members and 10 debris disk candidates, and analyzes the sub-stellar fraction and brown dwarf deficit.

Findings

29 new low-mass member candidates identified

10 debris disk candidates detected via IR excess

Sub-stellar objects constitute 8-15% of the cluster population

Abstract

We report the outcome of a deep multi-wavelength study of the IC2391 young open cluster. We aim at uncovering new low-mass and sub-stellar members of the cluster and identifying new debris disk objects. A 30*30 square arcmin area in IC 2391 was observed using the wide-field imager at the ESO 2.2m telescope. The completeness limits of the photometry at 3 sigma level are V=24.7, Rc=23.7 and Ic=23.0, faint enough to reveal sub-stellar members down to about 0.03 solar masses. Our membership criteria are based on the use of our optical data, in combination with JHKs magnitudes from the 2MASS catalog. We also estimate the physical parameters of the selected candidates. Debris disk candidates are identified on the basis of their infrared excess emission using near- and mid-infrared photometry from the Spitzer Space Telescope. Our optical survey, which has a limiting magnitude at 3 sigma level 1-2 mag fainter than previous optical surveys conducted in IC2391, revealed 29 new low-mass member candidates of the cluster. We estimate the contamination to be at least 50%. We constrain the fraction of sub-stellar objects in the range 8-15% and discuss possible explanations for the deficit of brown dwarfs in this cluster. We also identified 10 candidates in the cluster showing IR excess emission consistent with the presence of debris disks.