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Title: | High-resolution spectroscopy of the high-velocity hot post-AGB star IRAS 18379–1707 (LS 5112) |
Authors: | Ikonnikova, N. P. Parthasarathy, M. Dodin, A. V. Hubrig, S. Sarkar, G. |
Keywords: | stars: abundances – stars AGB and post-AGB – stars tmospheres – stars early- type – stars evolution – star individual: IRAS 18379–1707, 62 Ori |
Issue Date: | Oct-2019 |
Publisher: | Oxford University Press on behalf of the Royal Astronomical Society |
Citation: | Monthly Notices of the Royal Astronomical Society, Vol. 491, No. 4 |
Abstract: | The high-resolution ( R ∼ 48 000) optical spectrum of the B-type supergiant LS 5112, identified as the optical counterpart of the post-AGB candidate IRAS 18379–1707 is analysed. We report the detailed identifications of the observed absorption and emission features in the wavelength range 3700–9200 Å for the first time. The absorption line spectrum has been analysed using non-LTE model atmosphere techniques to determine stellar atmospheric parameters and chemical composition. We estimate T eff = 18 000 ± 1000 K, log g = 2.25 ± 0.08, ξ t = 10 ± 4kms − 1 , and v sin i = 37 ± 6kms − 1 , and the derived abundances indicate a metal-deficient ([M/H] ≈− 0.6) post-AGB star. Chemical abundances of eight different elements were obtained. The estimates of the CNO abundances in IRAS 18379– 1707 indicate that these elements are overabundant with [(C + N + O)/S] =+ 0.5 ± 0.2 suggesting that the products of helium burning have been brought to the surface as a result of third dredge-up on the AGB. From the absorption lines, we derived heliocentric radial velocity of V r =− 124.0 ± 0.4 km s − 1 . We have identified permitted emission lines of O I ,N I ,Na I , S II ,Si II ,C II ,Mg II , and Fe III . The nebula forbidden lines of [N I ], [O I ], [Fe II ], [N II ], [S II ], [Ni II ], and [Cr II ] have also been identified. The Balmer lines H α ,H β , and H γ show P-Cygni behaviour clearly indicating post-AGB mass-loss process in the object with the wind velocity up to 170 km s − 1 . |
Description: | Restricted Access © Royal Astronomical Society https://academic.oup.com/mnras/article/491/4/4829/5647366 |
URI: | http://prints.iiap.res.in/handle/2248/7396 |
ISSN: | 1365-2966 |
Appears in Collections: | IIAP Publications |
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High-resolution spectroscopy of the high-velocity hot post-AGB star IRAS.pdf Restricted Access | Restricted Access | 1.11 MB | Adobe PDF | View/Open Request a copy |
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