Cold Disks around Nearby Stars. A Search for Edgeworth-Kuiper Belt Analogues

We will use the unique photometric capabilities provided by Herschel to perform a deep and systematic survey for faint, cold debris disks around nearby stars.

Our sensitivity-limited Key Programme aims at finding and characterizing faint exo-solar analogues to the Edgeworth-Kuiper Belt in an unbiased, statistical sample of nearby FGK main-sequence stars. Our sample is volume-limited (distances < 20 pc) and spans a broad range of stellar ages – from ~0.1 to ~10 Gyr. All stars with known extrasolar planets within that distance are included; additionaly, some M- and A-type stars will be observed in collaboration with the DEBRIS Herschel OTKP, so that the whole sample covers a decade in stellar mass from 0.2 to 2 solar masses.

We will perform PACS and SPIRE photometric observations covering the wavelength range from 70 to 500 micron. PACS observations at 100 micron have been designed to detect the stellar photospheres down to the confusion noise with a signal to noise ratio at least 5. Observations in the other Herschel bands will allow us to characterize, model, and constrain the disks. As a result, it will be possible for us to reach fractional luminosities L_dust / L_★ of a few times 10^-7, close to the EKB level in our solar system.

This will provide an unprecedented lower limit to the fractional abundance of planetesimal systems, and act as a proxy to assess the presence of giant planets resembling the roles played by Neptune and Jupiter in the solar system. The proposed observations will provide new and unique evidence for the presence of mature planetary systems in the solar neighbourhood and, in turn, will address the universality of planets/planetary systems formation in disks around young stars.