Orbital properties of binary post-AGB stars
| العنوان: | Orbital properties of binary post-AGB stars |
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| المؤلفون: | Onno R. Pols, Gijs Nelemans, Hans Van Winckel, R. Manick, Christoffel Waelkens, Ana Escorza, Glenn-Michael Oomen, Devika Kamath |
| المصدر: | Astronomy & astrophysics, 620 Astronomy & Astrophysics, 620, pp. 1-21 Astronomy & Astrophysics, 620, 1-21 |
| سنة النشر: | 2018 |
| مصطلحات موضوعية: | Astronomy, Monte Carlo method, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, spectroscopic [Binaries], 0103 physical sciences, Asymptotic giant branch, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysique, Astrophysics::Galaxy Astrophysics, Physics, Orbital elements, Mass distribution, 010308 nuclear & particles physics, Astronomy and Astrophysics, Circumstellar matter, AGB and post-AGB [Stars], Astronomie, Accretion (astrophysics), Sciences de l'espace, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Circumbinary planet |
| الوصف: | Binary post-Asymptotic giant branch (post-AGB) stars are thought to be the products of a strong but poorly understood interaction during the AGB phase. The aim of this contribution is to update the orbital elements of a sample of galactic post-AGB binaries observed in a long-Term radial-velocity monitoring campaign by analysing these systems in a homogeneous way. Radial velocities are computed from high signal-To-noise spectra via a cross-correlation method. The radial-velocity curves are fitted by using both a least-squares algorithm and a Nelder-Mead simplex algorithm. We use a Monte Carlo method to compute uncertainties on the orbital elements. The resulting mass functions are used to derive a companion mass distribution by optimising the predicted to the observed cumulative mass-function distributions, after correcting for observational bias. As a result, we derive and update orbital elements for 33 galactic post-AGB binaries, among which 3 are new orbits. The orbital periods of the systems range from 100 to about 3000 days. Over 70% (23 out of 33) of our binaries have significant non-zero eccentricities ranging over all periods. Their orbits are non-circular even though the Roche-lobe radii are smaller than the maximum size of a typical AGB star and tidal circularisation should have been strong when the objects were on the AGB. We derive a distribution of companion masses that is peaked around 1.09 Mâ with a standard deviation of 0.62 Mâ. The large spread in companion masses highlights the diversity of post-AGB binary systems. Post-AGB binaries are often chemically peculiar, showing in their photospheres the result of an accretion process of circumstellar gas devoid of refractory elements. We find that only post-AGB stars with high effective temperatures (> 5500 K) in wide orbits are depleted in refractory elements, suggesting that re-Accretion of material from a circumbinary disc is an ongoing process. It appears, however, that depletion is inefficient for the closest orbits irrespective of the actual surface temperature. SCOPUS: ar.j info:eu-repo/semantics/published |
| وصف الملف: | 1 full-text file(s): application/pdf; application/pdf |
| اللغة: | English |
| تدمد: | 1432-0746 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a2d396fe1e24579fb431a742e8571235 http://arxiv.org/abs/1810.01842 |
| Rights: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....a2d396fe1e24579fb431a742e8571235 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 14320746 |
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