论文标题
Tess-Keck调查。十三。偏心的海王星,在TOI-1272周围有类似的质量外伴侣
The TESS-Keck Survey. XIII. An Eccentric Hot Neptune with a Similar-Mass Outer Companion around TOI-1272
论文作者
论文摘要
我们报告发现怪异的海王星和TOI-1272周围的非传输外行星的发现。我们根据观察到的转运持续时间与圆形轨道的预期持续时间之间的不匹配,确定了内行星的偏心性,轨道周期为3.3 d和$ r _ {\ rm p,b} = 4.1 \ pm 0.2 $ $ $ $ r_ \ oplus $。使用凯克天文台的雇用仪器的地面径向速度测量,我们测量了TOI-1272b的质量为$ m _ {\ rm p,b} = 25 \ pm 2 $ $ m_ \ oplus $。我们还确认了$ e_b = 0.34 \ pm 0.06 $的高偏心率,将TOI-1272B放置在最古怪的次型亚jovian中。我们使用这些RV测量值还可以在8.7-D轨道上识别一个非传输外伴侣,其质量为$ m _ {\ rm p,c} $ sin $ i = 27 \ pm 3 $ $ $ m_ \ oplus $和$ e_c \ e_c \ e_c \ simsim 0.35 $。动态稳定的行星空间 - 行星 - 尽管预期近距离偏心的海王星的圆形时间尺度很短,但仍允许TOI-1272b避免潮汐偏移。 TOI-1272b还保持$ f _ {\ rm env} \约11 \%$的信封质量分数,尽管其平衡温度很高,这意味着目前可能正在进行光蒸发。这个星球在“热海王星沙漠”中加入了少数短周期的海王星状行星,地层途径知之甚少。
We report the discovery of an eccentric hot Neptune and a non-transiting outer planet around TOI-1272. We identified the eccentricity of the inner planet, with an orbital period of 3.3 d and $R_{\rm p,b} = 4.1 \pm 0.2$ $R_\oplus$, based on a mismatch between the observed transit duration and the expected duration for a circular orbit. Using ground-based radial velocity measurements from the HIRES instrument at the Keck Observatory, we measured the mass of TOI-1272b to be $M_{\rm p,b} = 25 \pm 2$ $M_\oplus$. We also confirmed a high eccentricity of $e_b = 0.34 \pm 0.06$, placing TOI-1272b among the most eccentric well-characterized sub-Jovians. We used these RV measurements to also identify a non-transiting outer companion on an 8.7-d orbit with a similar mass of $M_{\rm p,c}$ sin$i= 27 \pm 3$ $M_\oplus$ and $e_c \lesssim 0.35$. Dynamically stable planet-planet interactions have likely allowed TOI-1272b to avoid tidal eccentricity decay despite the short circularization timescale expected for a close-in eccentric Neptune. TOI-1272b also maintains an envelope mass fraction of $f_{\rm env} \approx 11\%$ despite its high equilibrium temperature, implying that it may currently be undergoing photoevaporation. This planet joins a small population of short-period Neptune-like planets within the "Hot Neptune Desert" with a poorly understood formation pathway.