Improving the distances of post-AGB objects in the Milky Way

11th Pacific Rim Conference on Stellar Astrophysics: Physics and Chemistry of the Late Stages of Stellar Evolution

物理学;天文学

Vickers, Shane B.^1 ; Frew, David J.^2 ; Owers, Matt S.^1,3 ; Parker, Quentin A.^2,3 ; Bojii, Ivan S.^2

Department of Physics and Astronomy, Macquarie University, NSW

2109, Australia^1

Department of Physics, University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong^2

Australian Astronomical Observatory, PO Box 915, North Ryde

NSW

1670, Australia^3

关键词: Archival data;    Asymptotic giant branch;    Period-luminosity relations;    Physical characteristics;    Planetary nebulae;    Spectral energy distribution;    Stellar evolutions;    Wavelength ranges;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/728/7/072013/pdf
DOI  :  10.1088/1742-6596/728/7/072013

学科分类：天文学(综合)

来源: IOP

【 摘 要 】

Post-AGB (PAGB) stars are short-lived, low-intermediate mass objects transitioning from the asymptotic giant branch (AGB) to the white dwarf (WD) phase. These objects are characterised by a constant, core-mass dependent luminosity and a large infrared excess from the dusty envelope ejected at the top of the AGB. PAGB stars provide insights into the evolution of their direct descendants, planetary nebulae (PNe). Calculation of physical characteristics of PAGB are dependent on accurately determined distances scarcely available in the literature. Using the Torun catalogue for PAGB objects, supplemented with archival data, we have determined distances to the known population of Galactic PAGB stars. This is by modelling their spectral energy distributions (SED) with black bodies and numerically integrating over the entire wavelength range to determine the total integrated object flux. For most PAGB stars we assumed their luminosities are based on their positional characteristics and stellar evolution models. RV Tauri stars however are known to follow a period-luminosity relation (PLR) reminiscent of type-2 Cepheids. For these variable PAGB stars we determined their luminosities via the PLR and hence their distances. This allows us to overcome the biggest obstacle to characterising these poorly understood objects that play a vital part in Galactic chemical enrichment.