Constraints on Inner Disk Evolution Timescales: A Disk Census of the Eta Chamaeleontis Young Cluster

Author(s)

K. E., Jr. Haisch, R. Jayawardhana, J. Alves

Abstract

We present new L-prime band (3.8 micron) observations of stars in the

nearby ( 97pc) young ( 6 Myr) compact cluster around Eta Chamaeleontis,

obtained with the European Southern Observatory's Very Large Telescope

in Paranal, Chile. Our data, combined with JHKs photometry from the

2-Micron All Sky Survey, reveal that only two of the 12 members surveyed

harbor L-prime band excesses consistent with optically thick inner

disks; both are also likely accretors. Intriguingly, two other stars

with possible evidence for on-going accretion, albeit at very low rates,

do not show significant infrared excess. This may imply substantial

grain growth and/or partial clearing of the inner disk region, as

expected in planet formation scenarios. Our findings suggest that Eta

Cha stars are in an epoch when disks are rapidly evolving, perhaps due

to processes related to planet building, and provide further constraints

on inner disk lifetimes.

Organisation(s)

External organisation(s)

University of Toronto, Utah Valley State College, European Southern Observatory (Germany)

Journal

Bulletin of the American Astronomical Society

Volume

Pages

1365

ISSN

0002-7537

Publication date

12-2004

Peer reviewed

Yes

Austrian Fields of Science 2012

103004 Astrophysics

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