Chemically peculiar stars in eclipsing binary systems are rare objects that allow the derivation of fundamental stellar parameters and important information on evolutionary status and the origin of the observed chemical peculiarities. Here we present an investigation of the known eclipsing binary system BD+09 1467 = V680 Mon. Using spectra from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and own observations, we identify the primary component of the system as a mercury–manganese (HgMn/CP3) star (spectral type kB9 hB8 HeB9 V HgMn). Furthermore, photometric time series data from the Transiting Exoplanet Survey Satellite (TESS) indicate that the system is a ‘heartbeat star’, a rare class of eccentric binary stars with short-period orbits that exhibit a characteristic signature near the time of periastron in their light curves due to the tidal distortion of the components. Using all available photometric observations, we present an updated ephemeris and binary system parameters as derived from a modelling of the system with the elisa code, which indicate that the secondary star has an effective temperature of Teff = $8300_{-200}^{+200}$ (spectral type ∼A4). V680 Mon is only the fifth known eclipsing CP3 star, and the first one in a heartbeat binary. Furthermore, our results indicate that the star is located on the zero-age main sequence and a possible member of the open cluster NGC 2264. As such, it lends itself perfectly for detailed studies and may turn out to be a keystone in the understanding of the development of CP3 star peculiarities.

中文翻译：

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V680 Mon——一颗年轻的水银-锰星，处于食相心跳系统中

食双星系统中的化学特殊恒星是罕见的天体，可以推导基本恒星参数以及有关演化状态和观察到的化学特征起源的重要信息。在这里，我们对已知的食双星系统 BD+09 1467 = V680 Mon 进行了调查。使用来自大天空区域多目标光纤光谱望远镜 (LAMOST) 的光谱和自己的观察，我们确定该系统的主要成分是一颗汞-锰 (HgMn/CP3) 星（光谱类型 kB9 hB8 HeB9 V HgMn）。此外，来自凌日系外行星调查卫星 (TESS) 的光度时间序列数据表明，该系统是一颗“心跳星”，一类罕见的具有短周期轨道的偏心双星，由于成分的潮汐畸变，在其光变曲线中表现出接近近星点时间的特征特征。使用所有可用的光度观测，我们提供了更新的星历和双星系统参数，这些参数源自使用 elisa 代码的系统建模，这表明次星的有效温度为 Teff = $8300_{-200}^{+ 200}$（光谱类型~A4）。V680 Mon 只是已知的第五颗食 CP3 恒星，也是心跳双星中的第一颗。此外，我们的结果表明，这颗恒星位于零年龄主序带上，可能是疏散星团 NGC 2264 的成员。因此，