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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

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Vieira, R. G. [1] ; Gregorio-Hetem, J. [1] ; Hetem, Jr., A. [2] ; Stasinska, G. [3] ; Szczerba, R. [4]
Total Authors: 5
[1] Univ Sao Paulo, IAG, BR-05508900 Sao Paulo - Brazil
[2] Univ Fed ABC, CECS, BR-09210170 Santo Andre, SP - Brazil
[3] Observ Meudon, LUTH, F-92190 Meudon - France
[4] Nicholas Copernicus Astron Ctr, PL-87100 Torun - Poland
Total Affiliations: 4
Document type: Journal article
Source: Astronomy & Astrophysics; v. 526, FEB 2011.
Web of Science Citations: 7

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. (AU)

FAPESP's process: 08/01533-4 - Circumstellar envelopes of intermediate mass young stars
Grantee:Rodrigo Georgetti Vieira
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 05/00397-1 - Chemical evolution and galactic and extragalactic stellar populations by spectroscopy and imaging
Grantee:Beatriz Leonor Silveira Barbuy
Support type: Research Projects - Thematic Grants