论文标题
分析五个热后AGB候选者的高分辨率光谱中的吸收线
Analysis of absorption lines in the high resolution spectra of five hot post-AGB candidates
论文作者
论文摘要
From an analysis of absorption lines in the high resolution spectra we have derived the radial velocities, stellar parameters (Teff, gravity, wind-strength parameter logQ and projected rotational velocity) and abundances (C, N, O, and Si ) of IRAS 17460-3114, IRAS 18131-3008, IRAS 19336-0400, LSE 45 and LSE 163.发现丰度是太阳能的，除了IRAS 19336-0400的SI丰度低，LSE 163中的轻度CNO模式，其光谱分类以异常大的旋转速度旋转。将恒星参数信息与GAIA DR2数据相结合，我们能够得出绝对的大小，半径和亮度，并阐明对象的可能后AGB性质。 IRAS 17460-3114和IRAS 18131-3008被认为是巨大的OB星，而IRAS 19336-0400被发现是后AGB恒星，已经显示了光谱中的雾线。但是，尽管它们的参数与大型恒星的参数更加不一致，但我们无法确认LSE 45和LSE 163的本质。在这两种情况下，我们都发现光谱质量与源自AGB后进化轨迹的预测得出的差异。此外，LSE 45缺少IRAS 19336-0400在类似温度下存在于IRA中的烟丝线。在LSE 163的情况下，旋转速度（259 +/- 15 km/s）对于变为CSPN的恒星将非常大。这种旋转速度，高银河纬度，略大的径向速度和轻度CNO增强的结合表明了二元相互作用的历史。
From an analysis of absorption lines in the high resolution spectra we have derived the radial velocities, stellar parameters (Teff, gravity, wind-strength parameter logQ and projected rotational velocity) and abundances (C, N, O, and Si ) of IRAS 17460-3114, IRAS 18131-3008, IRAS 19336-0400, LSE 45 and LSE 163. Abundances are found to be solar, except for a low Si abundance in IRAS 19336-0400 and a mild CNO pattern in LSE 163, that rotates at an unusual large rotational velocity for its spectral classification. Combining the stellar parameters information with Gaia DR2 data we are able to derive absolute magnitudes, radii and luminosities and clarify the possible post-AGB nature of the objects. IRAS 17460-3114 and IRAS 18131-3008 are found to be massive OB stars, whereas IRAS 19336-0400 is found to be a post-AGB star, already showing nebular lines in the spectrum. However, we could not confirm the nature of LSE 45 and LSE 163 as post-AGB stars, although their parameters are much more inconsistent with those of massive stars. In both cases, we find a discrepancy between the spectroscopic mass and that derived from the predictions of post-AGB evolutionary tracks. In addition, LSE 45 lacks nebular lines, that are present in IRAS 19336-0400 at a similar temperature. In the case of LSE 163 the rotational velocity (259+/-15 km/s) would be extremely large for a star evolving to CSPN. The combination of this rotational velocity, the high Galactic latitude, slightly large radial velocity and mild CNO enhancement suggests a history of binary interaction.
