We systematically searched for gravity- and Rossby-mode period spacing patterns in Kepler eclipsing binaries with γ Doradus pulsators. These stars provide an excellent opportunity to test the theory of tidal synchronization and angular momentum transport in F- and A-type stars. We discovered 35 systems that show clear patterns, including the spectroscopic binary KIC 10080943. Combined with 45 non-eclipsing binaries with γ Dor components that have been found using pulsation timing, we measured their near-core rotation rates and asymptotic period spacings. We find that many stars are tidally locked if the orbital periods are shorter than 10 d, in which the near-core rotation periods given by the traditional approximation of rotation are consistent with the orbital period. Compared to the single stars, γ Dor stars in binaries tend to have slower near-core rotation rates, likely a consequence of tidal spin-down. We also find three stars that have extremely slow near-core rotation rates. To explain these, we hypothesize that unstable tidally excited oscillations can transfer angular momentum from the star to the orbit, and slow the star below synchronism, a process we refer to as ‘inverse tides’.

中文翻译：

---

潮汐对近核自转的影响：35 颗开普勒 γ Doradus 星的食食和光谱双星分析

我们系统地搜索了带有 γ Doradus 脉动器的开普勒食双星中的重力和罗斯比模式周期间隔模式。这些恒星提供了一个极好的机会来测试 F 型和 A 型恒星的潮汐同步和角动量传输理论。我们发现了 35 个显示清晰模式的系统，包括光谱双星 KIC 10080943。结合使用脉动计时发现的具有 γ Dor 分量的 45 个非食双星，我们测量了它们的近核心旋转速率和渐近周期间隔。我们发现，如果轨道周期小于 10 d，许多恒星会被潮汐锁定，其中传统近似自转给出的近核自转周期与轨道周期一致。相比单星，双星中的 γ Dor 星往往具有较慢的近核心自转率，这可能是潮汐自旋下降的结果。我们还发现了三颗近核心自转速度极慢的恒星。为了解释这些，我们假设不稳定的潮汐激发振荡可以将角动量从恒星转移到轨道，并使恒星减速至低于同步，我们将这一过程称为“逆潮汐”。