Exoplanets & Exomoons

TCF Periodogram’s High Sensitivity: A Method For Optimizing Detection Of Small Transiting Planets

By Keith Cowing
Status Report
August 9, 2023
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TCF Periodogram’s High Sensitivity: A Method For Optimizing Detection Of Small Transiting Planets
Periodogram analysis for Gaussian noise and a smaller planet with injected transit depth 68 ppm. See Figure 1 for a description of the panels — astro-ph.EP

We conduct a methodological study for statistically comparing the sensitivities of two periodograms for weak signal planet detection in transit surveys: the widely used Box-Least Squares (BLS) algorithm following light curve detrending and the Transit Comb Filter (TCF) algorithm following autoregressive ARIMA modeling.

Small depth transits are injected into light curves with different simulated noise characteristics. Two measures of spectral peak significance are examined: the periodogram signal-to-noise ratio (SNR) and a False Alarm Probability (FAP) based on the generalized extreme value distribution. The relative performance of the BLS and TCF algorithms for small planet detection is examined for a range of light curve characteristics, including orbital period, transit duration, depth, number of transits, and type of noise.

The TCF periodogram applied to ARIMA fit residuals with the SNR detection metric is preferred when short-memory autocorrelation is present in the detrended light curve and even when the light curve noise had white Gaussian noise. BLS is more sensitive to small planets only under limited circumstances with the FAP metric. BLS periodogram characteristics are inferior when autocorrelated noise is present. Application of these methods to TESS light curves with small exoplanets confirms our simulation results.

The study ends with a decision tree that advises transit survey scientists on procedures to detect small planets most efficiently. The use of ARIMA detrending and TCF periodograms can significantly improve the sensitivity of any transit survey with regularly spaced cadence.

Yash Gondhalekar, Eric D. Feigelson, Gabriel A. Caceres, Marco Montalto, Snehanshu Saha

Comments: 30 pages, 13 figures, submitted to AAS Journals
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2308.04282 [astro-ph.EP] (or arXiv:2308.04282v1 [astro-ph.EP] for this version)
Submission history
From: Yash Gondhalekar
[v1] Tue, 8 Aug 2023 14:24:53 UTC (12,710 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻