Dynamical evolution of titanium, strontium, and yttrium spots on the surface of the HgMn star HD 11753
Dynamical evolution of titanium, strontium, and yttrium spots on the surface of the HgMn star HD 11753
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HgMn星HD 11753表面钛、锶和钇斑点的动力学演化
DOI：
10.1051/0004-6361/200913775
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发表时间：
2010
影响因子：
6.5
通讯作者：
T. Hackman
中科院分区：
文献类型：
--
作者：
M. Briquet;H. Korhonen;J. F. González;S. Hubrig;T. Hackman
目标。我们收集了三颗典型的HgMn（汞锰）星HD 11753，HD 53244和HD 221507的大约100个高分辨率光谱，以寻找缓慢脉动的B类脉动和各种化学元素的表面不均匀分布。方法.经典的频率分析方法被用来检测线轮廓的变化，并确定变化的周期。进行多普勒成像重建，获得恒星表面化学元素丰度图。结果对于HD 11753，这是星星与最显着的变化，不同的光谱线轮廓的变化被检测到的Ti，Sr，Y，Zr和Hg，而对于HD 53244和HD 221507最可变的线轮廓分别属于元素Hg和Y。我们从径向速度的变化和属于非均匀分布元素的谱线的等效宽度推导出这三颗星的自转周期：Prot（HD 11753）= 9.54 d，Prot（HD 53244）= 6.16 d，Prot（HD 221507）= 1.93 d。对于HD 11753，多普勒成像技术被应用于使用相隔65天的两个数据集导出最易变元素Ti、Sr和Y的分布。多普勒成像重建的结果显示了显着的变化，表面分布的Ti二，S三，和YII之间的数据集，表明迄今没有很好地理解的物理过程中的恒星辐射信封，导致一个相当快的动态化学斑点的演变。
Aims. We gathered about 100 high-resolution spectra of three typical HgMn (mercury-manganese) stars, HD 11753, HD 53244, and HD 221507, to search for slowly pulsating B-like pulsations and surface inhomogeneous distribution of various chemical elements. Methods. Classical frequency analysis methods were used to detect line profile variability and to determine the variation period. Doppler imaging reconstruction was performed to obtain abundance maps of chemical elements on the stellar surface. Results. For HD 11753, which is the star with the most pronounced variability, distinct spectral line profile changes were detected for Ti, Sr, Y, Zr, and Hg, whereas for HD 53244 and HD 221507 the most variable line profiles belong to the elements Hg and Y, respectively. We derived rotation periods for all three stars from the variations of radial velocities and equivalent widths of spectral lines belonging to inhomogeneously distributed elements: Prot (HD 11753) = 9.54 d, Prot (HD 53244) = 6.16 d, and Prot (HD 221507) = 1.93 d. For HD 11753 the Doppler imaging technique was applied to derive the distribution of the most variable elements Ti, Sr, and Y using two datasets separated by ∼65 days. Results of Doppler imaging reconstruction revealed noticeable changes in the surface distributions of Ti ii ,S rii ,a nd Yii between the datasets, indicating the hitherto not well understood physical processes in stars with radiative envelopes that cause a rather fast dynamical chemical spot evolution.