Deficit of wide binaries in the eta Chamaeleontis young cluster

Details Deficit of wide binaries in the eta Chamaeleontis young cluster Deficit of wide binaries in the eta Chamaeleontis young cluster

2006-08-16

arxiv.org/abs/astro-ph/0608352v1

Astrophys.J.652:1572-1584,2006

Astronomy and Astrophysics

Astrophysics

Accepted by ApJ. 13 pages, 10 figures

Scientific paper

10.1086/508483

We have carried out a sensitive high-resolution imaging survey of stars in the young (6-8 Myr), nearby (97 pc) compact cluster around eta Chamaeleontis to search for stellar and sub-stellar companions. Given its youth and proximity, any sub-stellar companions are expected to be luminous, especially in the near infrared, and thus easier to detect next to their parent stars. Here, we present VLT/NACO adaptive optics imaging with companion detection limits for 17 eta Cha cluster members, and follow-up VLT/ISAAC near-infrared spectroscopy for companion candidates. The widest binary detected is ~0.2", corresponding to the projected separation 20 AU, despite our survey being sensitive down to sub-stellar companions outside 0.3", and planetary mass objects outside 0.5". This implies that the stellar companion probability outside 0.3" and the brown dwarf companion probability outside 0.5" are less than 0.16 with 95% confidence. We compare the wide binary frequency of eta Cha to that of the similarly aged TW Hydrae association, and estimate the statistical likelihood that the wide binary probability is equal in both groups to be < 2e-4. Even though the eta Cha cluster is relatively dense, stellar encounters in its present configuration cannot account for the relative deficit of wide binaries. We thus conclude that the difference in wide binary probability in these two groups provides strong evidence for multiplicity properties being dependent on environment. In two appendices we derive the projected separation probability distribution for binaries, used to constrain physical separations from observed projected separations, and summarize statistical tools useful for multiplicity studies.

Affiliated with

Also associated with

No associations

Rating

Deficit of wide binaries in the eta Chamaeleontis young 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 Deficit of wide binaries in the eta Chamaeleontis young cluster, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Deficit of wide binaries in the eta Chamaeleontis young cluster will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-389141