A 1.2 mm MAMBO survey of post-AGB stars

¹ INAF, Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania, Italy e-mail: cbuemi@oact.inaf.it
² INAF, Istituto di Radioastronomia, Sezione di Noto, CP 161, 96017 Noto (SR), Italy

Received: 24 March 2006
Accepted: 26 September 2006

Abstract

Aims.We performed a millimetric survey of a sample of 24 post-AGB stars aimed at searching for emission from circumstellar matter, in order to investigate the physical properties of the outer parts of the envelopes.

Methods.The observations were conducted using the 37-channel Max-Planck Millimeter Bolometer array at the 30-meter IRAM telescope. The continuum emission toward the detected sources was used to quantify the mass of the emitting dust. We combined our observations with data available in the literature to construct the spectral energy distribution (SED) of the sources. When the observational data covered a spectral range wide enough, some properties of circumstellar envelopes were derived by comparison with spectra computed using a radiative transfer code.

Results.Of the 24 objects in our sample, we detected millimetric continuum emission toward 11 sources. Two other sources were detected at a flux level close to 3σ. The derived circumstellar dust masses range between 0.4 and  , but these results are affected by the uncertainty about the source distances. The parameters derived from the SED fits are consistent with the values characteristic of this kind of object. As confirmed from the flux density extrapolated in the first light channels of the Atacama Large Millimetric Array, these sources could be good targets for future high-resolution mapping with the ALMA facility.