Spitzer Space Telescope study of disks in the young $σ$ Orionis cluster

Details Spitzer Space Telescope study of disks in the young $σ$ Orionis cluster Spitzer Space Telescope study of disks in the young $σ$ Orionis cluster

2007-01-16

arxiv.org/abs/astro-ph/0701476v1

Astrophys.J.662:1067-1081,2007

Astronomy and Astrophysics

Astrophysics

44pages, 17 figures. Sent to ApJ

Scientific paper

10.1086/513735

We report new Spitzer Space Telescope observations from the IRAC and MIPS instruments of the young (~ 3 Myr) sigma Orionis cluster. We identify 336 stars as members of the cluster using optical and near-infrared color magnitude diagrams. Using the spectral energy distribution (SED) slopes in the IRAC spectral range, we place objects in several classes: non-excess stars, stars with optically thick disks(like classical T Tauri stars), class I (protostellar) candidates, and stars with ``evolved disks''; the last exhibit smaller IRAC excesses than optically thick disk systems. In general, this classification agrees with the location expected in IRAC-MIPS color-color diagrams for these objects. We find that the evolved disk systems are mostly a combination of objects with optically thick but non-flared disks, suggesting grain growth and/or settling, and transition disks, systems in which the inner disk is partially or fully cleared of small dust. In all, we identify 7 transition disk candidates and 3 possible debris disk systems. As in other young stellar populations, the fraction of disks depends on the stellar mass, ranging from ~10% for stars in the Herbig Ae/Be mass range (>2 msun) to ~35% in the T Tauri mass range (1-0.1 msun). We find that the disk fraction does not decrease significantly toward the brown dwarf candidates (<0.1 msun). The IRAC infrared excesses found in stellar clusters and associations with and without central high mass stars are similar, suggesting that external photoevaporation is not very important in many clusters. Finally, we find no correlation between the X-ray luminosity and the disk infrared excess, suggesting that the X-rays are not strongly affected by disk accretion.

Affiliated with

Also associated with

No associations

Rating

Spitzer Space Telescope study of disks in the young $σ$ Orionis cluster does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Spitzer Space Telescope study of disks in the young $σ$ Orionis cluster, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spitzer Space Telescope study of disks in the young $σ$ Orionis cluster will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-188379