USAAAO — 2022 First Round

Figure 6 shows a 6-hr root-mean-square (rms) Combined Differential Photometric Precision (CDPP) curve for 150,000 stars observed by the Kepler space telescope. CDPP is a measure of the white noise contained in a light curve, so for a target with 6-hour CDPP of 100 parts per million (ppm), a 6-hour transit with depth 100 ppm would be considered a 1-σ detection. Figure 6: From Christiansen et al. (https://arxiv.org/abs/1208.0595). Original caption: The distri- bution of the 6-hour rms CDPP values with Kp magnitude for all Quarter 3 planetary targets. Consider a 1R☉ target with Kepler magnitude Kp = 13.5 that's among the best targets for its magnitude with respect to noise in Figure 6. Also consider three independent exoplanet scenarios for exoplanets with radii: • I. 0.5 R⊕ • II. 1 R⊕ • III. 10 R⊕ Using a 1 − σ detection threshold (and assuming 6-hour transit durations), which planet(s) transits would we likely fail to observe due to noise?