标题： 一颗位于半径谷的超地球和HD 307842周围的外行星候选体 显示英文标题

标题： A Transiting Super-Earth in the Radius Valley and An Outer Planet Candidate Around HD 307842

摘要： 我们报告了通过TESS发现的一颗凌星超级地球行星HD 307842 (TOI-784)的确认。 该行星周期为2.8天，径向速度（RV）测量限制其质量为9.67+0.83/-0.82 [地球质量]。 我们还报告了在外轨道上发现的另一个可能非凌星的行星候选者。 该行星候选者的可能周期约为20至63天，对应的RV半振幅预计在3.2到5.4 m/s之间，最小质量从12.6到31.1 [地球质量]。 凌星行星（行星b）的半径为1.93+0.11/-0.09 [地球半径]，导致平均密度为7.4+1.4/-1.2 g/cm^3，表明TOI-784b很可能是一颗岩石行星，尽管它的半径与亚海王星相当。 我们发现TOI-784b位于所谓的“半径谷”的下边缘，在半径与辐射平面中，这与光蒸发或核心驱动的质量损失预测一致。 TESS数据未揭示该行星候选者的显著凌星信号，我们的分析显示行星b和行星候选者的轨道倾角分别为88.60+0.84/-0.86度和<= 88.3-89.2度。 需要更多的径向速度观测来确定第二个物体的周期和质量，并搜索该系统中的额外行星。 显示英文摘要

摘要： We report the confirmation of a TESS-discovered transiting super-Earth planet orbiting a mid-G star, HD 307842 (TOI-784). The planet has a period of 2.8 days, and the radial velocity (RV) measurements constrain the mass to be 9.67+0.83/-0.82 [Earth Masses]. We also report the discovery of an additional planet candidate on an outer orbit that is most likely non-transiting. The possible periods of the planet candidate are approximately 20 to 63 days, with the corresponding RV semi-amplitudes expected to range from 3.2 to 5.4 m/s and minimum masses from 12.6 to 31.1 [Earth Masses]. The radius of the transiting planet (planet b) is 1.93+0.11/-0.09 [Earth Radii], which results in a mean density of 7.4+1.4/-1.2 g/cm^3 suggesting that TOI-784b is likely to be a rocky planet though it has a comparable radius to a sub-Neptune. We found TOI-784b is located at the lower edge of the so-called ``radius valley'' in the radius vs. insolation plane, which is consistent with the photoevaporation or core-powered mass loss prediction. The TESS data did not reveal any significant transit signal of the planet candidate, and our analysis shows that the orbital inclinations of planet b and the planet candidate are 88.60+0.84/-0.86 degrees and <= 88.3-89.2 degrees, respectively. More RV observations are needed to determine the period and mass of the second object, and search for additional planets in this system.