Eclipse Timing the Milky Way’s Gravitational Potential
Eclipse Timing the Milky Way’s Gravitational Potential
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DOI：
10.3847/2041-8213/ac5c43
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发表时间：
2021-12
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影响因子：
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通讯作者：
S. Chakrabarti;D. Stevens;J. Wright;R. Rafikov;P. Chang;T. Beatty;D. Huber
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作者：
S. Chakrabarti;D. Stevens;J. Wright;R. Rafikov;P. Chang;T. Beatty;D. Huber
我们表明，一个小的，但可测量的转变，在日食中点时间的日食双星（EBs）的10.1秒以上的十年基线可以用来直接测量银河系中的恒星在银河系的加速度从太阳的距离为1千秒差距。我们认为贡献的周期漂移率从动力学机制以外的银河系的引力场，并表明，银河系加速度可以可靠地测量使用开普勒电子束的样本与轨道和恒星参数的文献。我们在这里估计的潮汐衰变的贡献是一个上限，假设恒星不是潮汐同步的。我们发现大约有200个分离的EB，估计时间精度优于0.5秒，其他动力学效应是次主导的银河信号。我们说明了一个原型的方法，精确定时EB使用档案开普勒光变曲线和现代合成HST光变曲线（提供了一个十年的基线）。这种新的方法建立了一个现实的可能性，约束暗物质的子结构和银河系的潜力，使用日食计时测量银河系加速度，沿着与其他新兴的新方法，包括脉冲星计时和极端精确的径向速度观测。该加速度信号随时间二次增长。因此，考虑到在不久的将来为遥远的EB建立的基线，我们可以期望在未来通过JWST和罗马太空望远镜等太空任务来测量周期漂移。
We show that a small but measurable shift in the eclipse midpoint time of eclipsing binary (EBs) stars of ∼0.1 s over a decade baseline can be used to directly measure the Galactic acceleration of stars in the Milky Way at ∼kiloparsec distances from the Sun. We consider contributions to the period drift rate from dynamical mechanisms other than the Galaxy’s gravitational field and show that the Galactic acceleration can be reliably measured using a sample of Kepler EBs with orbital and stellar parameters from the literature. The contribution from tidal decay we estimate here is an upper limit assuming the stars are not tidally synchronized. We find there are about 200 detached EBs that have estimated timing precision better than 0.5 s, and for which other dynamical effects are subdominant to the Galactic signal. We illustrate the method with a prototypical, precisely timed EB using an archival Kepler light curve and a modern synthetic HST light curve (which provides a decade baseline). This novel method establishes a realistic possibility to constrain dark matter substructure and the Galactic potential using eclipse timing to measure Galactic accelerations, along with other emerging new methods, including pulsar timing and extreme-precision radial velocity observations. This acceleration signal grows quadratically with time. Therefore, given baselines established in the near future for distant EBs, we can expect to measure the period drift in the future with space missions like JWST and the Roman Space Telescope.