ANALYSIS OF THE PICO DOS DIAS SURVEY HERBIG Ae/Be CANDIDATES
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
---|---|
Data(s) |
18/04/2012
18/04/2012
2010
|
Resumo |
A large sample of Herbig Ae/Be (HAeBe) candidates, distributed in different Galactic regions south to declination +30 degrees, were identified by the Pico dos Dias Survey (a search for young stellar objects based on IRAS colors). Most of the candidates are nearby or associated with star-forming clouds, but several others are considered isolated objects. Aiming to verify the young nature of 93 HAeBe candidates, we searched for additional information that could be useful to confirm if they are pre-main-sequence (PMS) stars or evolved objects, which coincidentally show similar IRAS colors. By adopting a spectral index that is related to the amount of infrared excess and the shape of the spectral energy distribution, we have classified the sample according to three groups, which are analyzed on the basis of (1) circumstellar luminosity; (2) spatial distribution; (3) optical polarization; (4) near-infrared colors; (5) stellar parameters (mass, age, effective temperature); and (5) intensity of emission lines. Our analysis indicates that only 76% of the studied sample, mainly the group with intermediate to low levels of circumstellar emission, can be more confidently considered PMS stars. The nature of the remaining stars, which are in the other group that contains the highest levels of infrared excess, remains to be confirmed. They share the same characteristics of evolved objects, requiring complementary studies in order to correctly classify them. At least seven objects show characteristics typical of post-asymptotic giant branch or proto-planetary nebulae. FAPESP[00/06954-6] FAPESP[2005/00397-1] FAPESP[2001/12589-1] |
Identificador |
ASTRONOMICAL JOURNAL, v.139, n.1, p.27-38, 2010 0004-6256 http://producao.usp.br/handle/BDPI/15678 10.1088/0004-6256/139/1/27 |
Idioma(s) |
eng |
Publicador |
IOP PUBLISHING LTD |
Relação |
Astronomical Journal |
Direitos |
closedAccess Copyright IOP PUBLISHING LTD |
Palavras-Chave | #circumstellar matter #stars: fundamental parameters #stars: pre-main sequence #T-TAURI STARS #NEAR-INFRARED PHOTOMETRY #INTERMEDIATE-MASS STARS #YOUNG STELLAR OBJECTS #POINT-SOURCE CATALOG #POLARIZATION #DUST #AE #CLASSIFICATION #POLARIMETRY #Astronomy & Astrophysics |
Tipo |
article original article publishedVersion |