Earth-mass exoplanets are difficult to detect. The Dispersed Matter Planet Project (DMPP) identifies stars that are likely to host the most detectable low-mass exoplanets. The star DMPP-3 (HD 42936) shows signs of circumstellar absorption, indicative of mass loss from ablating planets. Here, we report the radial velocity discovery of a highly eccentric 507 d binary companion and a hot super-Earth-mass planet in a 6.67 d orbit around the primary star. DMPP-3A is a solar-type star while DMPP-3B is just massive enough to fuse hydrogen. The binary, with semi-major axis 1.22 ± 0.02 au, is considerably tighter than others known to host planets orbiting only one of the component stars. The configuration of the DMPP-3 planetary system is rare and indicates dynamical interactions, though the evolutionary history is not entirely clear. DMPP-3A b is possibly the residual core of a giant planet precursor, consistent with the inferred circumstellar gas shroud.

地球质量系外行星很难被发现。分散物质星球计划（DMPP）确定了可能携带最可探测的低质量系外行星的恒星。DMPP-3（HD 42936）恒星显示出星际吸收的迹象，表明消融行星造成了质量损失。在这里，我们报告了一个高偏心507 d双星伴星和一个热的超地球质量行星在一次恒星周围的6.67 d轨道上的径向速度发现。DMPP-3A是太阳型恒星，而DMPP-3B刚好足以融合氢。半长轴为1.22±0.02 au的双星比已知的仅容纳一颗组成恒星绕行运行的行星要紧密得多。DMPP-3行星系统的构造很少见，并表明存在动力学相互作用，尽管进化史还不十分清楚。