Large Binocular Telescope Hunt for Observable Signatures of Terrestrial Planetary Systems (LBTI-HOSTS)
Why look for observable signatures of terrestrial planetary systems?
About 20% of field stars have cold debris disks created by the collisions and evaporation of planetesimals. Much less is known about warm circumstellar dust, such as that found in the vicinity of the Earth in our own system. This dust is generated in asteroidal collisions and cometary breakups, and current detection limits are at best ~500 times our system's level, i.e. 500 zodi. LBTI-HOSTS will be the first survey capable of measuring exozodi at the 10 zodi level (3). Exozodi of this brightness would be the major source of astrophysical noise for a future space telescope aimed at direct imaging and spectroscopy of habitable zone terrestrial planets. Detections of warm dust will also reveal new information about planetary system architectures and evolution.
The survey will enter operation in early 2014 and continue for four years in order to survey about 50 nearby stars. Some stars have known outer disks, and we will find out if there is a connection between the cold planetesimal belts that produce the known dust and inner dust. In some cases, we may be able to infer the presence of otherwise undetected planets in the systems from the geometry of the dust belts.