HD 8673 hosts a massive exoplanet in a highly eccentric orbit (e = 0.723). Based on two epochs of speckle interferometry a previous publication identified a candidate stellar companion. We observed HD 8673 multiple times with the 10 m Keck II telescope, the 5 m Hale telescope, the 3.63 m Advanced Electro-Optical System telescope, and the 1.5 m Palomar telescope in a variety of filters with the aim of confirming and characterizing the stellar companion. We did not detect the candidate companion, which we now conclude was a false detection, but we did detect a fainter companion. We collected astrometry and photometry of the companion on six epochs in a variety of filters. The measured differential photometry enabled us to determine that the companion is an early M dwarf with a mass estimate of 0.33–0.45 M. The companion has a projected separation of 10 AU, which is one of the smallest projected separations of an exoplanet host binary system. Based on the limited astrometry collected, we are able to constrain the orbit of the stellar companion to a semimajor axis of 35–60 AU, an eccentricity 0.5, and an inclination of 75°–85°. The stellar companion has likely strongly influenced the orbit of the exoplanet and quite possibly explains its high eccentricity.
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机译：HD 8673在一个高度偏心的轨道（e = 0.723）中拥有一颗大型系外行星。基于斑点干涉测量的两个时代，以前的出版物确定了候选恒星伴侣。我们使用10 m Keck II望远镜，5 m Hale望远镜，3.63 m先进电子光学系统望远镜和1.5 m Palomar望远镜在各种滤镜中多次观察了HD 8673，以确认和表征恒星伴侣。我们没有检测到候选同伴，我们现在得出结论是错误的检测，但是我们确实检测到了较暗的同伴。我们在六个过滤器的六个时期收集了同伴的天体测量法和光度法。测得的差分光度法使我们能够确定该伴星是早期M矮星，其质量估计值为0.33-0.45M。该伴星的预计间隔为10 AU，这是系外行星宿主双星系统的最小预计间隔之一。 。基于收集的有限天文数据，我们能够将恒星伴星的轨道限制在35-60 AU的半长轴，0.5的偏心率和75°-85°的倾角上。恒星伴星可能强烈影响了系外行星的轨道，并很有可能解释了其高偏心率。
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