I searched for the ground state 6.8 and 9.2 GHz hyperfine transitions of rubidium and cesium toward M- and L-dwarfs that show Rb and Cs optical resonance lines. The optical lines can pump the hyperfine transitions, potentially forming masers. These spin-flip transitions of Rb and Cs are the principal transitions used in atomic clocks (the ¹³³Cs hyperfine transition defines the second). If they are detected in stellar atmospheres, these transitions would provide exceptionally precise clocks that can be used as accelerometers, as exoplanet detectors, as probes of the predictions of general relativity, as probes of light propagation effects, and as a means to do fundamental physics with telescopes. Observations of 21 M- and L-dwarfs, however, show no evidence for Rb or Cs maser action, and a previous survey of giant stars made no Rb maser detections.

我搜索了and和铯向M-和L-矮星的基态6.8和9.2 GHz超精细跃迁，这些跃迁显示了Rb和Cs光学共振线。光学线会泵浦超精细跃迁，可能形成脉动。Rb和Cs的自旋翻转跃迁是原子钟中的主要跃迁（¹³³CS超精细过渡定义了第二个）。如果在恒星大气中检测到它们，那么这些跃迁将提供异常精确的时钟，这些时钟可用作加速度计，系外行星探测器，广义相对论预测的探针，光传播效应的探针以及进行基础物理学的手段用望远镜。然而，对21个M和L矮星的观测没有发现Rb或Cs激射作用的证据，先前对巨星的调查也没有发现Rb激射。