Scaling K2. II. Assembly of a Fully Automated C5 Planet Candidate Catalog Using EDI-Vetter

Zink, Jon K.; Hardegree-Ullman, Kevin K.; Christiansen, Jessie L.; Dressing, Courtney D.; Crossfield, Ian J. M.; Petigura, Erik A.; Schlieder, Joshua E.; Ciardi, David R.

doi:10.3847/1538-3881/ab7448

Cited by 25 publications

(65 citation statements)

References 81 publications

(129 reference statements)

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“…The fourth planet candidate in EPIC 211562654 is confirmed. For EPIC 211711685, we found a single event in addition to the component claimed by Zink et al (2020). EPIC 212119244 was also confirmed, albeit with low S/N at twice of the period given by Zink et al (2020).…”

Section: Comparison With Other Searchessupporting

confidence: 64%

“…For EPIC 211711685, we found a single event in addition to the component claimed by Zink et al (2020). EPIC 212119244 was also confirmed, albeit with low S/N at twice of the period given by Zink et al (2020). There remained two candidates (EPIC 211953244 and 212020330) that we could not confirm, in spite of extensive testing.…”

Section: Comparison With Other Searchescontrasting

confidence: 55%

“…Interestingly, while testing their planet vetting pipeline on C05, Zink et al (2020) found eight candidates that do not enter in the list of Kruse et al (2019). At the same time, they could not verify 49% of the candidates of Kruse et al (2019).…”

Section: Comparison With Other Searchesmentioning

confidence: 99%

“…Focusing only on Campaign 5, in the basic verification, we relied primarily on the 115 host stars with 138 planet candidates of Kruse et al (2019). In addition to this quite recent work, we also tested the 8 candidates in Zink et al (2020). The basic analysis was performed on the PET database, but in unresolved cases, we also used the KEP database.…”

Section: Comparison With Other Searchesmentioning

confidence: 99%

“…4.2, it is quite surprising to see the systematic difference and the large scatter between the two studies. To add to this discrepancy, the injected signal test performed by Zink et al (2020) indicates that the EVEREST transit depths are lower by some 2.3% as they should be. Unfortunately, we have no answer at this moment on the source of the apparently significant discrepancy between our results and those of Kruse et al (2019).…”

Section: Comparison With Other Searchesmentioning

confidence: 99%

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More planetary candidates from K2 Campaign 5 using TRAN_K2

Kovács

2020

A&A

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Context. The exquisite precision of space-based photometric surveys and the unavoidable presence of instrumental systematics and intrinsic stellar variability call for the development of sophisticated methods that distinguish these signal components from those caused by planetary transits. Aims. Here, we introduce the standalone Fortran code tran_k2 to search for planetary transits under the colored noise of stellar variability and instrumental effects. We use this code to perform a survey to uncover new candidates. Methods. Stellar variability is represented by a Fourier series and, when necessary, by an autoregressive model aimed at avoiding excessive Gibbs overshoots at the edges. For the treatment of systematics, a cotrending and an external parameter decorrelation were employed by using cotrending stars with low stellar variability as well as the chip position and the background flux level at the target. The filtering was done within the framework of the standard weighted least squares, where the weights are determined iteratively, to allow a robust fit and to separate the transit signal from stellar variability and systematics. Once the periods of the transit components are determined from the filtered data by the box-fitting least squares method, we reconstruct the full signal and determine the transit parameters with a higher accuracy. This step greatly reduces the excessive attenuation of the transit depths and minimizes shape deformation. Results. We tested the code on the field of Campaign 5 of the K2 mission. We detected 98% of the systems with all their candidate planets as previously reported by other authors. We then surveyed the whole field and discovered 15 new systems. An additional three planets were found in three multiplanetary systems, and two more planets were found in a previously known single-planet system.

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Section: Comparison With Other Searchessupporting

confidence: 64%

Section: Comparison With Other Searchescontrasting

confidence: 55%

Section: Comparison With Other Searchesmentioning

confidence: 99%

Section: Comparison With Other Searchesmentioning

confidence: 99%

Section: Comparison With Other Searchesmentioning

confidence: 99%

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More planetary candidates from K2 Campaign 5 using TRAN_K2

Kovács

2020

A&A

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Occurrence rates of planets orbiting M Stars: applying ABC to Kepler DR25, Gaia DR2, and 2MASS data

Hsu

Ford

Terrien

2020

Monthly Notices of the Royal Astronomical Society

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We present robust planet occurrence rates for Kepler planet candidates around M stars for planet radii Rp = 0.5 − 4 R⊕ and orbital periods P = 0.5 − 256 days using the approximate Bayesian computation (ABC) technique. This work incorporates the final Kepler DR25 planet candidate catalog and data products and augments them with updated stellar properties using Gaia DR2 and 2MASS PSC. We apply a set of selection criteria to select a sample of 1,746 Kepler M dwarf targets that host 89 associated planet candidates. These early M dwarfs and late K dwarfs were selected from cross-referenced targets using several photometric quality flags from Gaia DR2 and color-magnitude cuts using 2MASS magnitudes. We estimate a habitable zone occurrence rate of $f_{\textrm {M,HZ}} = 0.33^{+0.10}_{-0.12}$ for planets with 0.75 − 1.5 R⊕ size. We caution that occurrence rate estimates for Kepler M stars are sensitive to the choice of prior due to the small sample of target stars and planet candidates. For example, we find an occurrence rate of $4.2^{+0.6}_{-0.6}$ or $8.4^{+1.2}_{-1.1}$ planets per M dwarf (integrating over Rp = 0.5 − 4 R⊕ and P = 0.5 − 256 days) for our two choices of prior. These occurrence rates are greater than those for FGK dwarf target when compared at the same range of orbital periods, but similar to occurrence rates when computed as a function of equivalent stellar insolation. Combining our result with recent studies of exoplanet architectures indicates that most, and potentially all, early-M dwarfs harbor planetary systems.

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tfaw survey – I. Wavelet-based denoising of K2 light curves. Discovery and validation of two new Earth-sized planets in K2 campaign 1

Ser

Fors

2020

Monthly Notices of the Royal Astronomical Society

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The wavelet-based detrending and denoising method TFAW is applied for the first time to EVEREST 2.0-corrected light curves to further improve the photometric precision of almost all K2 observing campaigns (C1-C8, C12-C18). The performance of both methods is evaluated in terms of 6 hr combined differential photometric precision (CDPP), simulated transit detection efficiency, and planet characterization in different SNR regimes. On average, TFAW median 6hr CDPP is $\sim 30\%$ better than the one achieved by EVEREST 2.0 for all observing campaigns. Using the transit least-squares (TLS) algorithm, we show that the transit detection efficiency for simulated Earth-Sun-like systems is ∼8.5 × higher for TFAW-corrected light curves than for EVEREST 2.0 ones. Using the light curves of two confirmed exoplanets, K2-44 b (high-SNR) and K2-298 b (low-SNR), we show that TFAW yields better MCMC posterior distributions, transit parameters compatible with the cataloged ones but with smaller uncertainties and narrows the credibility intervals. We use the combination of TFAW’s improved photometric precision and TLS enhancement of the signal detection efficiency for weak signals to search for new transit candidates in K2 observing campaign 1. We report the discovery of two new K2-C1 Earth-sized planets statistically validated, using the vespa software: EPIC 201170410.02, with a radius of 1.047$^{+0.276}_{-0.257}R_{\oplus }$ planet orbiting an M-type star, and EPIC 201757695.02, with a radius of 0.908$^{+0.059}_{-0.064}R_{\oplus }$ planet orbiting a K-type star. EPIC 201757695.02 is the 9-th smallest planet ever discovered in K2-C1, and the 39-th smallest in all K2 campaigns.

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Scaling K2. II. Assembly of a Fully Automated C5 Planet Candidate Catalog Using EDI-Vetter

Cited by 25 publications

References 81 publications

More planetary candidates from K2 Campaign 5 using TRAN_K2

More planetary candidates from K2 Campaign 5 using TRAN_K2

Occurrence rates of planets orbiting M Stars: applying ABC to Kepler DR25, Gaia DR2, and 2MASS data

tfaw survey – I. Wavelet-based denoising of K2 light curves. Discovery and validation of two new Earth-sized planets in K2 campaign 1

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