论文标题
高精度过境光曲线中的Exomoon指标
Exomoon indicators in high-precision transit light curves
论文作者
论文摘要
虽然太阳系含有比行星高约20倍的月球，但到目前为止已知的成千上万的外星行星中的任何一个都没有确认月亮。 Tools for an uncomplicated identification of the most promising exomoon candidates could be beneficial to streamline follow-up studies.} Here we study three exomoon indicators that emerge if well-established planet-only models are fitted to a planet-moon transit light curve: transit timing variations (TTVs), transit duration variations (TDVs), and apparent planetary transit radius variations （TRV）。我们在现实条件下重新评估了TTV和TDV系列中先前提出的Exomoon特征。我们模拟具有单个月亮的过渡系外行星的光曲线。然后将这些模型的光曲线与仅行星的过境模型一起拟合，假装没有月亮，我们探索所得的TTV，TDV和TRV系列以获取月球的证据。先前描述的具有月球外行星的TTV-TDV图中的椭圆形仅适用于高密度月亮。低密度卫星由于对联合行星 - 月球传输的光度贡献而扭曲了TTV和TDV系列的正弦形状。足够大的月亮可以产生可观察到的宿主行星的明显明显TRV。我们发现，开普勒和柏拉图在检测模拟的明亮（$ m_v = 8 $）星周周围检测出外部诱导的TRV效果时也具有类似的性能。但是，这些恒星在开普勒样品中很少见，但在柏拉图样品中会很丰富。此外，柏拉图的较高节奏产生了更强的TTV信号。过境半径测量序列的周期图可以表明月球的存在。带有月亮的系外行星的TTV和TDV系列可能比以前假设的更为复杂。我们建议TRV可能是在大型系外行星调查中识别外容器的一种更有希望的方法。
While the solar system contains about 20 times more moons than planets, no moon has been confirmed around any of the thousands of extrasolar planets known so far. Tools for an uncomplicated identification of the most promising exomoon candidates could be beneficial to streamline follow-up studies.} Here we study three exomoon indicators that emerge if well-established planet-only models are fitted to a planet-moon transit light curve: transit timing variations (TTVs), transit duration variations (TDVs), and apparent planetary transit radius variations (TRVs). We re-evaluate under realistic conditions the previously proposed exomoon signatures in the TTV and TDV series. We simulate light curves of a transiting exoplanet with a single moon. These model light curves are then fitted with a planet-only transit model, pretending there were no moon, and we explore the resulting TTV, TDV, and TRV series for evidence of the moon. The previously described ellipse in the TTV-TDV diagram of an exoplanet with a moon emerges only for high-density moons. Low-density moons distort the sinusoidal shapes of the TTV and the TDV series due to their photometric contribution to the combined planet-moon transit. Sufficiently large moons can produce periodic apparent TRVs of their host planets that could be observable. We find that Kepler and PLATO have similar performances in detecting the exomoon-induced TRV effect around simulated bright ($m_V=8$) stars. These stars, however, are rare in the Kepler sample but will be abundant in the PLATO sample. Moreover, PLATO's higher cadence yields a stronger TTV signal. The periodogram of the sequence of transit radius measurements can indicate the presence of a moon. The TTV and TDV series of exoplanets with moons can be more complex than previously assumed. We propose that TRVs could be a more promising means to identify exomoons in large exoplanet surveys.
