Young stars and their circumstellar disks in the Sigma Orionis cluster

Abstract

The sigma Orionis cluster is a young association evolving under the disruptive influence of its massive O-star namesake. We are analysing this cluster as part of a program to characterise the influence of O-stars on the early stages of stellar evolution. At an age of approximately 4 Myr, this cluster is at a crucial stage in terms of disk evolution and therefore it is a key case to better constrain disk dissipation timescales. We have obtained RI photometry and optical spectroscopy of the sigma Ori cluster; we have analysed the Li I and Na I features to establish cluster membership. We have thus gathered a unique sample of spectroscopically confirmed low-mass cluster members and brown dwarfs. Disk frequencies from K-band excesses from 2MASS suggest that less than 7% of the very low-mass sigma Ori members have disks, in stark contrast with even younger clusters (e.g. Trapezium). However, near-infrared disk frequencies have to be taken with caution. We are currently undertaking an L-band (imaging) and mid-infrared (imaging and spectroscopy) program to identify and probe the properties of circumstellar disks around young stars in this cluster. Preliminary results indicate that at least 30% of cluster members have circumstellar disks.

Citation

M. Oliveira, J., D. Jeffries, R., Th. van Loon, J., & J. Kenyon, M. (2004). Young stars and their circumstellar disks in the Sigma Orionis cluster. In Open Issues in Local Star Formation (55–62). https://doi.org/10.1007/1-4020-2600-5_6

• Conference Name: Open Issues in Local Star Formation and Early Stellar Evolution
• Conference Location: Ouro Preto, Minas Gerais, Brazil
• Start Date: Apr 5, 2003
• End Date: Apr 10, 2003
• Online Publication Date: Apr 18, 2006
• Publication Date: Dec 31, 2004
• Publicly Available Date: May 26, 2023
• Publisher: Springer
• Pages: 55–62
• Series Title: Astrophysics and Space Science Library
• Series ISSN: 0067-0057
• Book Title: Open Issues in Local Star Formation
• ISBN: 978-1-4020-1755-1
• DOI: https://doi.org/10.1007/1-4020-2600-5_6
• Keywords: astrophysics, stars, Cluster Member, Stellar Evolution, Young Star, Circumstellar Disk, Brown Dwarf