| Description |
Nearly all young stars harbour circumstellar disks, that serve as the reservoir
for mass accretion onto the star, and later become the birthplace of planetary
systems. After the disappearance of the gas component from the disk a dusty
debris disk is formed that is believed to mark the location of the planetesimal
belt as well. For outlining the evolution of such debris disks traditionally open
clusters and field stars were studied, however we argue that the recently
discovered young moving groups are more suitable objects for such analyses, due
to their proximity and good coverage of the first 50 Myr period of the planetary
system evolution. In this proposal we request 70/160 um Herschel/PACS photometric
observations for so-far unobserved moving group members. These observations will
provide a complete coverage of all known members within 80 pc of five nearby
young moving groups (beta Pic Moving Group, Tucana-Horologium, Carina, Columba,
and Argus), in the A to K spectral range. Based on the new observations we will
identify new debris disks, characterize the disk population within individual
moving groups, and study disk evolution by comparing the groups of different
ages. The results will be used to verify predictions of the self-stirring model
of the evolution of planetesimal disks. We will also compare the properties of
debris disks in groups of the same age, looking for additional .environmental.
parameters that affect disk structure over a whole moving group. Our study will
be a significant contribution to the census of debris disks in young moving
groups, increasing the number of observed sources by a factor of 1.5. Since
Spitzer could perform only a limited census and the so-far approved Herschel
programs added very few additional moving group obervations, our programme is
expected to have a high legacy value. |
