发现两颗造父变星的蓝色伴星：WW Car和FN Vel
Discovery of blue companions to two southern Cepheids: WW Car and FN Vel
摘要：
在Ca Ⅱ H+K谱线区域获得了大量经典造父变星的高色散谱。这些光谱的分析使我们能够检测到一个强大的巴耳末线的存在，H $ε$，为几个造父变星，解释为一个蓝色的伴侣的签名：一个足够明亮的蓝色伴侣造父变星的存在下，在一个可辨别的加强CaII H + Hepatine线相对于CaII K线。我们调查了103颗造父变星，包括那些已知的热伴星（B5-B6主序星），以测试该方法。我们可以确认WW Car和FN Vel的伴星的存在（前者的存在以前只是怀疑），我们发现这些伴星是蓝热星。当双星系统中轨道速度的变化不能被揭示，而其他的双星检测方法效率不高时，该方法仍然有效。
英文摘要：
A large number of high-dispersion spectra of classical Cepheids were obtained in the region of the CaII H+K spectral lines. The analysis of these spectra allowed us to detect the presence of a strong Balmer line, H$ε$, for several Cepheids, interpreted as the signature of a blue companion: the presence of a sufficiently bright blue companion to the Cepheid results in a discernible strengthening of the CaII H + Hepsilon line relative to the CaII K line. We investigated 103 Cepheids, including those with known hot companions (B5-B6 main-sequence stars) in order to test the method. We could confirm the presence of a companion to WW Car and FN Vel (the existence of the former was only suspected before) and we found that these companions are blue hot stars. The method remains efficient when the orbital velocity changes in a binary system cannot be revealed and other methods of binarity detection are not efficient.
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