Astronomy and Astrophysics, volume 352, 228-238 (1999/12-1)
Transitional YSOs: candidates from flat-spectrum IRAS sources.
MAGNIER E.A., VOLP A.W., LAAN K., VAN DEN ANCKER M.E. and WATERS L.B.F.M.
Abstract (from CDS):
We are searching for Young Stellar Objects (YSOs) near the boundary between protostars and pre-main-sequence objects, what we term Transitional YSOs. We have identified a sample of 125 objects as candidate transitional YSOs on the basis of IRAS colors and the optical appearance on POSS plates. We have obtained optical and near-IR imaging of 82 objects accessible from the Northern Hemisphere and optical images of 62 sources accessible from the South. We also created deconvolved 60µm IRAS images of all sources. We have classified the objects on the basis of their morphology in the optical and near-IR images. We find that the majority of our objects are associated with star-forming regions, confirming our expectation that the bulk of these objects are YSOs. Of the 125 objects, 28 have a variety of characteristics very similar to other transitional YSOs, while another 22 show some of these characteristics. Furthermore we have found seven objects to be good candidates for members of the Herbig Ae/Be stellar group, of which three are newly identified as such. We have placed a set of images for each of the objects in the archives of the Centre de Donnees astronomique de Strasbourg (CDS).