The nearby evolved stars survey - I. JCMT/SCUBA-2 submillimetre detection of the detached shell of U Antliae
Ventura, Paolo; Goldman, Steven R.; Boyer, Martha L.; Greaves, Jane; Kemper, Francisca; Liu, Tie; Shinnaga, Hiroko; Izumiura, Hideyuki; Matsuura, Mikako; Cami, Jan; Scicluna, Peter; Toalá, Jesús A.; van Loon, Jacco Th; Kim, Hyosun; McDonald, Iain; Marshall, Jonathan P.; He, Jinhua; Zijlstra, Albert A.; Srinivasan, Sundar; Rau, Gioia; Lagadec, Eric; Holland, Wayne; Wallström, Sofia H. J.; Dharmawardena, Thavisha E.; Wouterloot, Jan G. A.; Trejo, Alfonso; Jones, Olivia
Taiwan, Germany, Mexico, United States, United Kingdom, China, Chile, Hong Kong SAR, Belgium, South Korea, Italy, France, Japan, Canada
Abstract
We present the highest resolution single-dish submillimetre observations of the detached shell source U Antliae to date. The observations were obtained at 450 and 850 {μ}m with SCUBA-2 instrument on the James Clerk Maxwell Telescope as part of the Nearby Evolved Stars Survey. The emission at 850 {μ}m peaks at 40 arcsec with hints of a second peak seen at ∼20 arcsec. The emission can be traced out to a radius of 56 arcsec at a 3σ level. The outer peak observed at 850 {μ}m 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 ± 0.3) × 10-5 M⊙ and established that the thermal pulse that gave rise to the detached shell occurred 3500 ± 500 yr ago.