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In the young system of WASP-18 the coronal emission is almost two orders of magnitude lower than expected for a star of its spectral type openParF6closePar and age openPar 800 MyrclosePar. The puzzling behavior could be explained as due to tidal interaction with its very massive hot Jupiter openPar10 M J closePar that prevents the formation of a magnetic dynamo in the shallow convective zone of the star and of thus of the corona. Here we want to observe the system of KELT-24 which is very similar to WASP-18. It is formed by an F5 star orbited by a massive hot Jupiter every 5 days. A measurement of its X-ray flux and luminosity derived from a 25 ks XMM-EPIC exposure can tell us if KELT-24 behaves like a young F type star of Hyades or if its X-ray activity is quenched by the interaction with its 5 M_J hot Jupiter.

在WASP-18年轻恒星系统中，其日冕辐射（coronal emission）相较于光谱型为F6、年龄为800百万年的恒星，几乎低了两个数量级。这种反常现象可通过该系统与质量达10倍木星质量（M_J）的大质量热木星（hot Jupiter）之间的潮汐相互作用加以解释：该相互作用会抑制恒星浅对流区内磁发电机（magnetic dynamo）的形成，进而无法产生日冕结构与辐射。本文旨在观测与WASP-18极为相似的KELT-24系统，该系统由一颗F5型恒星与一颗每5天绕其公转一次的大质量热木星构成。通过25千秒（ks）的XMM-EPIC曝光获取的观测数据，对其X射线通量与光度进行测量，即可判断KELT-24是表现出毕星团（Hyades）中年轻F型恒星的X射线活动特征，还是其X射线活动因与质量为5倍木星质量的热木星之间的相互作用而被淬灭。