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Article Dans Une Revue Astronomy and Astrophysics - A&A Année : 2011

Distinguishing post-AGB impostors in a sample of pre-main sequence stars

Résumé

Context. A sample of 27 sources, cataloged as pre-main sequence stars by the Pico dos Dias Survey (PDS), is analyzed to investigate a possible contamination by post-AGB stars. The far-infrared excess due to dust present in the circumstellar envelope is typical of both categories: young stars and objects that have already left the main sequence and are suffering severe mass loss.
Aims: The two known post-AGB stars in our sample inspired us to seek for other very likely or possible post-AGB objects among PDS sources previously suggested to be Herbig Ae/Be stars, by revisiting the observational database of this sample.
Methods: In a comparative study with well known post-AGBs, several characteristics were evaluated: (i) parameters related to the circumstellar emission; (ii) spatial distribution to verify the background contribution from dark clouds; (iii) spectral features; and (iv) optical and infrared colors.
Results: These characteristics suggest that seven objects of the studied sample are very likely post-AGBs, five are possible post-AGBs, eight are unlikely post-AGBs, and the nature of seven objects remains unclear.

Dates et versions

hal-03785275 , version 1 (23-09-2022)

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Citer

R. G. Vieira, J. Gregorio-Hetem, A. Hetem, Grazyna Stasinska, Ryszard Szczerba. Distinguishing post-AGB impostors in a sample of pre-main sequence stars. Astronomy and Astrophysics - A&A, 2011, 526, pp.24. ⟨10.1051/0004-6361/201015592⟩. ⟨hal-03785275⟩
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