论文标题
使用恒星伪密度的过境模型中的隐式偏见
Implicit biases in transit models using stellar pseudo-density
论文作者
论文摘要
运输技术是迄今为止大多数系外行星发现的原因。这些行星表征这些行星涉及对其运输剖面的仔细建模。一种常见的技术涉及使用像密度的参数$ \tildeρ$表达过境持续时间，通常称为“圆形密度”。最值得注意的是，开普勒项目 - 迄今为止的最大的公交灯曲面分析 - 在$ \tildeρ$上采用了线性先验。在这里，我们表明，由于$ \tildeρ$与过境持续时间之间的非线性关系，这种先前的偏见是影响参数（$ b $）的偏见。这种偏见有利于低值（$ b \ lyssim 0.3 $），并且强烈地不散发高值（$ b \ gtrsim 0.7 $），除非过境信噪比足以提供对$ b $的独立约束，这是对开普勒行星的大部分不满足的标准。星球与星形半径比率，$ r $，由于$ r { - } b $协方差也有偏见。因此，中位开普勒DR25目标遭受$ 1.6 \％$的系统低估$ r $。我们提出了一种纠正这些偏见并首先避免它们的技术。
The transit technique is responsible for the majority of exoplanet discoveries to date. Characterizing these planets involves careful modeling of their transit profiles. A common technique involves expressing the transit duration using a density-like parameter, $\tildeρ$, often called the "circular density." Most notably, the Kepler project -- the largest analysis of transit lightcurves to date -- adopted a linear prior on $\tildeρ$. Here, we show that such a prior biases measurements of impact parameter, $b$, due to the non-linear relationship between $\tildeρ$ and transit duration. This bias slightly favors low values ($b \lesssim 0.3$) and strongly disfavors high values ($b \gtrsim 0.7$) unless transit signal-to-noise ratio is sufficient to provide an independent constraint on $b$, a criterion that is not satisfied for the majority of Kepler planets. Planet-to-star radius ratio, $r$, is also biased due to $r{-}b$ covariance. Consequently, the median Kepler DR25 target suffers a $1.6\%$ systematic underestimate of $r$. We present a techniques for correcting these biases and for avoiding them in the first place.
