Details

Autor(en) / Beteiligte

• Szczerba, R.
• Hajduk, M.
• Pavlenko, Ya. V.
• Hrivnak, B. J.
• Kaminsky, B. M.
• Volk, K.
• Siódmiak, N.
• Gezer, I.
• Začs, L.
• Pych, W.
• Sarna, M.

Titel

Validating post-AGB candidates in the LMC and SMC using SALT spectra

Ist Teil von

• Astronomy and astrophysics (Berlin), 2020-09, Vol.641, p.A142

Ort / Verlag

Heidelberg: EDP Sciences

Erscheinungsjahr

2020

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• We selected a sample of post-AGB candidates in the Magellanic Clouds on the basis of their near- and mid-infrared colour characteristics. Fifteen of the most optically bright post-AGB candidates were observed with the South African Large Telescope in order to determine their stellar parameters and thus to validate or discriminate their nature as post-AGB objects in the Magellanic Clouds. The spectral types of absorption-line objects were estimated according to the MK classification, and effective temperatures were obtained by means of stellar atmosphere modelling. Emission-line objects were classified on the basis of the fluxes of the emission lines and the presence of the continuum. Out of 15 observed objects, only 4 appear to be genuine post-AGB stars (27%). In the SMC, 1 out of 4 is post-AGB, and in the LMC, 3 out 11 are post-AGB objects. Thus, we can conclude that the selected region in the colour-colour diagram, while selecting the genuine post-AGB objects, overlaps severely with other types of objects, in particular young stellar objects and planetary nebulae. Additional classification criteria are required to distinguish between post-AGB stars and other types of objects. In particular, photometry at far-IR wavelengths would greatly assist in distinguishing young stellar objects from evolved ones. On the other hand, we showed that the low-resolution optical spectra appear to be sufficient to determine whether the candidates are post-AGB objects.