LAMOST views δ Scuti pulsating stars
LAMOST views δ Scuti pulsating stars
复制标题
DOI：
10.1093/mnras/stx3185
复制
发表时间：
2017-07
影响因子：
4.8
通讯作者：
Sheng-Bang Qian;L.-J. Li;J. He;Junke Zhang;Li-ying Zhu;Zhaobin Han
中科院分区：
文献类型：
--
作者：
Sheng-Bang Qian;L.-J. Li;J. He;Junke Zhang;Li-ying Zhu;Zhaobin Han
截至2017年6月16日，LAMOST观测到约766颗盾牌座δ星。确定了525个变量的恒星大气参数，同时获得了所有样本的光谱类型。本文对这些光谱数据进行了编目。我们探测到一组不寻常的冷变星（UCV），它们与正常的盾牌座δ星（NDST）不同。在H-R图和对数g-T图上，UCV都远远超出了脉动不稳定性跳变的红边。它们的有效温度均低于6700 K，周期在0.09 ~ 0.22 d之间。正如预期的那样，NDST的金属丰度接近太阳的金属丰度，而UCV的金属丰度略低于NDST。周期和恒星大气参数分布的双峰都是由UCV的存在引起的。在排除这些UCV的情况下，发现有效温度、引力加速度和金属丰度都与NDST的脉动周期相关，并讨论了它们的物理性质和演化状态。对这些UCV的探测表明，大约25%的已知盾牌座δ恒星可能被错误分类。然而，如果其中一些被证实是脉动星，它们将是一种新型的对流子，它们的研究将有助于揭示理论上的不稳定域和太阳型恒星的脉动与对流之间的相互作用理论。同时，还探测到88颗盾牌座δ星可能是双星或多星系统的候选者。
About 766 delta Scuti stars were observed by LAMOST by 2017 June 16. Stellar atmospheric parameters of 525 variables were determined, while spectral types were obtained for all samples. In the paper, those spectroscopic data are catalogued. We detect a group of unusual and cool variable stars (UCVs) that are distinguished from the normal delta Scuti stars (NDSTs). On the H-R diagram and the log g-T diagram, the UCVs are far beyond the red edge of pulsational instability trip. Their effective temperatures are lower than 6700 K with periods in the range from 0.09 to 0.22 d. NDSTs have metallicity close to that of the Sun as expected, while UCVs are slightly metal poor than NDSTs. The two peaks on the distributions of the period and stellar atmospheric parameters are all caused by the existence of UCVs. When those UCVs are excluded, it is discovered that the effective temperature, the gravitational acceleration, and the metallicity all are correlated with the pulsating period for NDSTs and their physical properties and evolutionary states are discussed. Detection of those UCVs indicates that about 25 per cent of the known delta Scuti stars may be misclassified. However, if some of them are confirmed to be pulsating stars, they will be a new-type pulsator and their investigations will shed light on theoretical instability domains and on the theories of interacting between the pulsation and the convection of solar-type stars. Meanwhile, 88 delta Scuti stars are detected to be the candidates of binary or multiple systems.