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


Full text
Sartori, Marilia J. [1] ; Gregorio-Hetem, Jane [2] ; Rodrigues, Claudia V. [3] ; Hetem, Jr., Annibal [4] ; Batalha, Celso [5]
Total Authors: 5
[1] MCT, Lab Nacl Astrofis, BR-37504364 Itajuba, MG - Brazil
[2] Univ Sao Paulo, IAG, BR-05508900 Sao Paulo - Brazil
[3] MCT, Inst Nacl Pesquisas Espaciais, BR-12227010 Sao Jose Dos Campos, SP - Brazil
[4] FAENG, Fundacao Santo Andre, BR-09060650 Santo Andre, SP - Brazil
[5] Evergreen Valley Coll, San Jose, CA 95135 - USA
Total Affiliations: 5
Document type: Journal article
Source: ASTRONOMICAL JOURNAL; v. 139, n. 1, p. 27-38, JAN 2010.
Web of Science Citations: 14

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. (AU)

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
FAPESP's process: 01/12589-1 - Stars, the interstellar medium and their interrelationships
Grantee:Antônio Mário Magalhães
Support type: Research Projects - Thematic Grants