The Nearby Evolved Stars Survey: I. JCMT/SCUBA-2 Sub-millimetre
  detection of the detached shell of U Antliae
  We present the highest resolution single-dish submillimetre observations of
the detached shell source U Antliae to date. The observations were obtained at
$450~\micron$ and $850~\micron$ with SCUBA-2 instrument on the James Clerk
Maxwell Telescope as part of the Nearby Evolved Stars Survey. The emission at
$850~\micron$ peaks at $40\arcsec$ with hints of a second peak seen at $\sim
20\arcsec$. The emission can be traced out to a radius of $56\arcsec$ at a
$3\sigma$ level. The outer peak observed at $850~\micron$ aligns well with the
peak observed at Herschel/PACS wavelengths. With the help of spectral energy
distribution fitting and radiative transfer calculations of multiple-shell
models for the circumstellar envelope, we explore the various shell structures
and the variation of grain sizes along the in the circumstellar envelope. We
determine a total shell dust mass of $(2.0 \pm 0.3) \times 10^{-5}$ M$_{\odot}$
and established that the thermal pulse which gave rise to the detached shell
occurred 3500 $\pm$ 500 years ago.
