Measuring Transit Signal Recovery in the Kepler Pipeline I: Individual Events
Jessie L. Christiansen, Bruce D. Clarke, Christopher J. Burke, Jon M. Jenkins, Thomas S. Barclay, Eric B. Ford, Michael R. Haas, Shawn Seader, Jeffrey Claiborne… 展开作者
Jessie L. Christiansen, Bruce D. Clarke, Christopher J. Burke, Jon M. Jenkins, Thomas S. Barclay, Eric B. Ford, Michael R. Haas, Shawn Seader, Jeffrey Claiborne Smith, Susan E. Thompson, Joseph D. Twicken
The Kepler Mission was designed to measure the frequency of Earth-size planets in the habitable zone of Sun-like stars. A crucial component for recovering the underlying planet population from a sample of detected planets is understanding the completeness of that sample - what fraction of the planets that could have been discovered in a given data set were actually detected. Here we outline the information required to determine the sample completeness, and describe an experiment to address a specific aspect of that question, which is the issue of transit signal recovery. We investigate the extent to which the Kepler pipeline preserves individual transit signals by injecting simulated transits into the pixel-level data, processing the modified pixels through the pipeline, and comparing the measured transit signal-to-noise ratio (SNR) to that expected without perturbation by the pipeline. We inject simulated transit signals across the full focal plane for a set of observations of length 89 days. On average, we find that the SNR of the injected signal is recovered at MS = 0.9973(+/-0.0012)xBS-0.0151(+/-0.0049), where MS is the measured SNR and BS is the baseline, or expected, SNR. The 1σ width of the distribution around this correlation is +/-2.64%. We discuss the pipeline processes that cause the measured SNR to deviate significantly from the baseline SNR; these are primarily the handling of data adjacent to spacecraft re-pointings and the removal of harmonics prior to the measurement of the SNR. Finally we outline the further work required to characterise the completeness of the Kepler pipeline.
Measuring Transit Signal Recovery in the Kepler Pipeline. III. Completeness of the Q1-Q17 DR24 Planet Candidate Catalogue, with Important Caveats for Occurrence Rate Calculations
随着开普勒管道的每一个新版本和产生的行星候选目录,对基础行星种群的更新测量只能通过开普勒管道探测效率的相应测量来恢复。在这里,我们介绍了用于生成Q1-Q17 DR 24行星候选目录(Coughlin等人,2016)的管道(版本9.2)的灵敏度测量。我们通过将模拟的凌日行星注入到整个开普勒焦平面上159,013个目标的像素级数据中来测量这一点,并检查恢复率。与以前版本的开普勒管道不同,我们发现测量的探测效率具有很强的周期依赖性,较长(>40天)的周期比较短的周期具有明显较低的可探测性,部分原因是错误地实施否决权。因此,9.2管线的灵敏度不能像管线的先前版本那样被转换为候选行星信号的信号强度的简单一维函数。我们报告了基于Q1-Q17 DR 24行星候选目录的发生率计算的影响,并为执行此类计算提供了重要的警告和建议。和以前一样,我们提供了整个注入行星参数表以及它们是否被管道恢复,使读者能够在他们选择的行星和/或恒星参数空间中获得管道检测灵敏度。
We identify targets in the Kepler field that may be characterized by transit timing variations (TTVs) and are detectable by the Transiting Exoplanet Survey Satellite (TESS). Despite the reduced signal-to-noise ratio of TESS transits compared to Kepler, we recover 48 transits from 13 systems in Sectors 14, 15, 26, 40 and 41. We find strong evidence of a nontransiting perturber orbiting Kepler-396 (KOI-2672) and explore two possible cases of a third planet in that system that could explain the measured transit times. We update the ephemerides and mass constraints where possible at KOI-70 (Kepler…
In this work we empirically measure the detection efficiency of Kepler pipeline used to create the final Kepler Threshold Crossing Event (TCE; Twicken et al. 2016) and planet candidate catalogs (Thompson et al. 2018), a necessary ingredient for occurrence rate calculations using these lists. By injecting simulated signals into the calibrated pixel data and processing those pixels through the pipeline as normal, we quantify the detection probability of signals as a function of their signal strength and orbital period. In addition we investigate the dependence of the detection efficiency on para…
A Search for Lost Planets in the Kepler Multi-planet Systems and the Discovery of the Long-period, Neptune-sized Exoplanet Kepler-150 f
在开普勒任务发现的4700颗已确认的行星和行星候选者中,绝大多数是由开普勒管道首次发现的。在管道中,在发现过境信号后,与这些过境相关的所有数据点都会被删除,从而创建一个充满漏洞的“瑞士奶酪”般的光曲线,然后用于后续的过境搜索。这些黑洞可能会使另一颗行星无法探测(或“丢失”)。我们研究了114颗恒星的样本,其中有$3+$确认的行星,以评估这种“瑞士奶酪”的影响。模拟确定了凌日行星由于凌日遮蔽而丢失的概率很低,但不可忽略,在$P=400-500$天的周期范围内丢失的$\sim3.3\%$达到平台。然后,我们对所有行星凌日进行建模,并减去每个恒星的凌日信号,恢复凌日数据点,并使用开普勒管道搜索凌日减去的(即,transit-cleaned)光变曲线。然而,管道没有发现任何可信的新过境信号。这证明了开普勒管道选择使用传输掩蔽而不是传输相减的有效性和鲁棒性。然而,对所有凌日减去数据的后续视觉搜索,这使得更容易视觉识别新的凌日,揭示了一个新的海王星大小的系外行星(开普勒-150 f)的存在和一个可能的假阳性(开普勒-208)的潜在单一凌日。开普勒-150 f($P=637.2$天,$R_{\rm{P}}=3.64^{+0.52}_{-0.39}$ R $_{\oplus}$)的确认与$>99.998\%$的信心,使用行星多重性参数,假阳性概率分析和过境持续时间分析的组合。
Early analyses of exoplanet statistics from the Kepler Mission revealed that a model population of multiple-planet systems with low mutual inclinations (${\sim1^{\circ}-2^{\circ}}$) adequately describes the multiple-transiting systems but underpredicts the number of single-transiting systems. This so-called "Kepler dichotomy" signals the existence of a sub-population of multi-planet systems possessing larger mutual inclinations. However, the details of these inclinations remain uncertain. In this work, we derive constraints on the intrinsic mutual inclination distribution by statistically expl…
If a transiting exoplanet has a moon, that moon could be detected directly from the transit it produces itself, or indirectly via the transit timing variations it produces in its parent planet. There is a range of parameter space where the Kepler Space Telescope is sensitive to the TTVs exomoons might produce, though the moons themselves would be too small to detect photometrically via their own transits. The Earth's Moon, for example, produces TTVs of 2.6 minutes amplitude by causing our planet to move around their mutual centre of mass. This is more than Kepler's short-cadence interval of 1 …
We identify a set of planetary systems observed by Kepler that merit transit timing variation (TTV) analysis given the orbital periods of transiting planets, the uncertainties for their transit times and the number of transits observed during the Kepler mission. We confirm the planetary nature of 4 KOIs within multicandidate systems. We forward model each of the planetary systems identified to determine which systems are likely to yield mass constraints that may be significantly improved upon with follow-up transit observations. We find projected TTVs diverge by more than 90 minutes after 6000…
Exomoons represent a crucial missing puzzle piece in our efforts to understand extrasolar planetary systems. To address this deficiency, we here describe an exomoon survey of 70 cool, giant transiting exoplanet candidates found by Kepler. We identify only one which exhibits a moon-like signal that passes a battery of vetting tests: Kepler-1708 b. We show that Kepler-1708 b is a statistically validated Jupiter-sized planet orbiting a Sun-like quiescent star at ~1.6AU. The signal of the exomoon candidate, Kepler-1708 b-i, is a 4.8-sigma effect and is persistent across different instrumental detr…
No correlation between the Transit-Depth Metallicity of Kepler gas giant confirmed and candidates planets: A Bayesian Approach
以前试图研究开普勒气体巨行星的凌日深度和恒星金属丰度之间的相关性,导致了不同的结果。据报道,开普勒(Q1-Q12)气态巨行星候选者与开普勒输入星表(KIC)中的[Fe/H]值和半径估计为5- 20 R $_\odot$之间存在微弱的显著负相关。随着最后一个开普勒目录(Q1-Q17)的发布,我们现在拥有最大的系外行星均匀样本。这使得能够对这种相关性进行可靠的统计分析。在目前的工作中,我们修改这种相关性,贝叶斯框架内,两个大的同质样本:确认和完成。我们扩展了一个层次模型,以考虑所研究的样本中的假阳性。我们的统计分析表明凌日深度与恒星金属丰度之间没有相关性。我们没有发现这种相关性的证据,这一事实将对行星形成理论和巨行星的内部结构产生影响。
Transit Timing Observations from Kepler: III. Confirmation of 4 Multiple Planet Systems by a Fourier-Domain Study of Anti-correlated Transit Timing Variations
Planet Hunters: Assessing the Kepler Inventory of Short Period Planets
我们提出的结果,从开普勒科学任务的前33.5天(季度1)的系外行星过境的行星猎人公民科学项目的数据搜索。行星猎人招募公众成员通过万维网在公开发布的开普勒光变曲线中视觉识别凌日。超过24,000名志愿者审查了开普勒第一季度的数据集。我们根据行星猎人的探测结果,研究了短周期(< 15天)轨道上\geq 2 R \oplus行星的丰度。我们提出了这些结果,以及人类分类器的检测效率的分析,以确定行星过境,包括比较开普勒清单的行星候选人。虽然性能下降迅速为较小的半径,\geq 4 R \oplus行星猎人\geq 85%的效率确定过境信号的行星周期小于15天的开普勒样本的目标恒星。我们对模拟凌日的高效率以及对大多数开普勒\geq 4 R \oplus行星的恢复表明,开普勒对\geq 4 R \oplus短周期行星的库存接近完成。
Modeling Kepler transit light curves as false positives: Rejection of blend scenarios for Kepler-9, and validation of Kepler-9d, a super-Earth-size planet in a multiple system
Kepler-289 is a three-planet system containing two sub-Neptunes and one cool giant planet orbiting a young, Sun-like star. All three planets exhibit transit timing variations (TTVs), with both adjacent planet pairs having orbital periods close to the 2:1 orbital resonance. We observe two transits of Kepler-289c with the Wide-field InfraRed Camera (WIRC) on the 200" Hale Telescope at Palomar Observatory, using diffuser-assisted photometry to achieve space-like photometric precision from the ground. These new transit observations extend the original four-year Kepler TTV baseline by an additional…
Accounting for Incompleteness due to Transit Multiplicity in Kepler Planet Occurrence Rates
我们调查的作用,行星探测顺序在开普勒行星探测管道中发挥作用。开普勒管道通常按照信号强度递减(MES)的顺序检测行星。我们发现,凌日的可探测性经历了额外的$5.5\%$和$15.9\%$的效率损失,期间分别为$<200$天和$>200$天,当检测到最强的信号过境后,在多行星系统。我们提供了一种方法来确定过境概率的多行星系统的经验开普勒数据集边缘化。此外,由于检测效率似乎是一个函数的检测顺序,我们讨论的排序统计,影响每个检测顺序的半径和周期分布。我们的发生率数据集包括来自加利福尼亚开普勒调查(CKS),盖亚DR2和星震学的半径测量更新。我们的群体模型与Burke et al.(2015)的结果一致,但现在包括对多重分布的改进估计。从我们获得的模型参数,我们发现,只有$4.0\pm4.6\%$的类太阳GK矮星拥有一颗行星。这种过剩是小于以前的研究,可以很好地与修改后的泊松分布建模,这表明开普勒二分法可以占包括多重检测效率的影响。使用我们的修正泊松模型,我们预计行星的平均数量是$5.86\pm0.18$行星每GK矮星的半径和周期参数空间的开普勒。
A Gas Giant Circumbinary Planet Transiting the F Star Primary of the Eclipsing Binary Star KIC 4862625 and the Independent Discovery and Characterization of the two transiting planets in the Kepler-47 System
我们报告发现了一颗凌日的气态巨环双星行星,它围绕食双星KIC 4862625运行,并描述了我们独立发现的两颗绕开普勒47运行的凌日行星(Orosz et al. 2012)。我们描述了一个简单的和半自动化的程序,用于识别个人过境的光变曲线,并提出我们的后续测量的两个circumbinary系统。在KIC 4862625系统中,这颗半径为0.52+/-0.018 RJup的行星每138天公转一次,并遮蔽了1.47+/-0.08 MSun,1.7 +/-0.06 RSun的F8 IV主星,产生了与食双星配置相当的非周期凌日。我们的最佳拟合模型表明轨道的半长轴为0.64 AU,并且稍微偏心,e=0.1。对于Kepler-47系统,我们确认了Orosz et al.(2012)的结果。KIC 4862625 A的径向速度调制是通过光谱和光度测量的,即通过多普勒增强,并产生类似的结果。
The exomoon candidate Kepler-1708 b-i was recently reported using two transits of Kepler data. Supported by a 1% false-positive probability, the candidate is promising but requires follow-up observations to confirm/reject its validity. In this paper, we consider the detectability of the exomoon candidate's transit, most specifically in the next window (March 2023) using the WFC3 instrument aboard the Hubble Space Telescope (HST). Using realistic noise estimates, accounting for the visit-long trends, and propagating the model posteriors derived using the Kepler data, we perform 75 injection-rec…
Exoplanet Transit Timing Variations (TTVs) caused by gravitational forces between planets can be used to determine planetary masses and orbital parameters. Most of the observed TTVs are small and sinusoidal in time, leading to degeneracies between the masses and orbital parameters. Here we report a TTV analysis of Kepler-90g and Kepler-90h, which exhibit large TTVs up to 25 hours. With optimization, we find a unique solution which allows us to constrain all of the orbital parameters. The best fit masses for Kepler-90g and 90h are $15.0^{+0.9}_{-0.8}$ $M_{\bigoplus}$ (Earth mass) and $203^{+5}_…