论文标题
TOI-2196 b：热海王星沙漠中的稀有星球过渡G型星星
TOI-2196 b: Rare planet in the hot Neptune desert transiting a G-type star
论文作者
论文摘要
热海王星沙漠中高度辐照的行星通常很小（后部r <2），岩石是岩石巨人，或者是半径> 1 rjup的气体巨头。在这里，我们报告了苔丝在27区发现的G型星的1.2天轨道上的中型行星TOI-2196。我们用竖琴光谱仪收集了42个径向速度测量值，以确定质量。 TOI-2196 b的半径为3.51 +/- 0.15后部，结合质量为26.0 +/- 1.3 mearth，导致大量密度为3.31 +0.51-0.43 g/cm3。因此，半径意味着该行星是一个亚nepune，尽管密度是海王星的密度的两倍。 HARPS径向速度的显着趋势表明，存在较低的距离，质量分别为220天和0.65 MJUP，假设零偏心率为零。行星B的短期表示，对于零反照率和各向同性发射，高平衡温度为1860 +/- 20 K。这将行星放在热海王星沙漠中，加入了近年来发现的这个参数空间中的一群行星。这些行星表明，热海王星沙漠可以分为两部分，用于平衡温度> 1800 k的行星：一个热的亚北北泥沙漠，没有行星，半径为1.8-3后方，而后jovian s沙漠则是5-12的半径。需要在此参数空间中更多的行星来进一步研究这一发现。 TOI-2196 B的行星内部结构模型与H/HE大气质量分数在0.4％至3％之间一致，其平均值为岩石内部的0.7％。我们估计了这个星球可能在年轻时损失的质量数量，我们发现，尽管群众损失可能很大，但地球没有改变特征：它是诞生的，它是一个小挥发性富裕的星球，目前仍然是一个。
Highly irradiated planets in the hot Neptune desert are usually either small (R < 2 Rearth) and rocky or they are gas giants with radii of >1 Rjup. Here, we report on the intermediate-sized planet TOI-2196 on a 1.2 day orbit around a G-type star discovered by TESS in sector 27. We collected 42 radial velocity measurements with the HARPS spectrograph to determine the mass. The radius of TOI-2196 b is 3.51 +/- 0.15 Rearth, which, combined with the mass of 26.0 +/- 1.3 Mearth, results in a bulk density of 3.31+0.51-0.43 g/cm3. Hence, the radius implies that this planet is a sub-Neptune, although the density is twice than that of Neptune. A significant trend in the HARPS radial velocities points to the presence of a distant companion with a lower limit on the period and mass of 220 days and 0.65 Mjup, respectively, assuming zero eccentricity. The short period of planet b implies a high equilibrium temperature of 1860 +/- 20 K, for zero albedo and isotropic emission. This places the planet in the hot Neptune desert, joining a group of very few planets in this parameter space discovered in recent years. These planets suggest that the hot Neptune desert may be divided in two parts for planets with equilibrium temperatures of > 1800 K: a hot sub-Neptune desert devoid of planets with radii of 1.8-3 Rearth and a sub-Jovian desert for radii of 5-12 Rearth. More planets in this parameter space are needed to further investigate this finding. Planetary interior structure models of TOI-2196 b are consistent with a H/He atmosphere mass fraction between 0.4 % and 3 %, with a mean value of 0.7 % on top of a rocky interior. We estimated the amount of mass this planet might have lost at a young age, and we find that while the mass loss could have been significant, the planet had not changed in terms of character: it was born as a small volatile-rich planet, and it remains one at present.
