Scaling K2. V. Statistical Validation of 60 New Exoplanets From K2 Campaigns 2–18

Abstract

The NASA K2 mission, salvaged from the hardware failures of the Kepler telescope, has continued Kepler’s planet-hunting success. It has revealed nearly 500 transiting planets around the ecliptic plane, many of which are the subject of further study, and over 1000 additional candidates. Here we present the results of an ongoing project to follow-up and statistically validate new K2 planets, in particular to identify promising new targets for further characterization. By analyzing the reconnaissance spectra, high-resolution imaging, centroid variations, and statistical likelihood of the signals of 91 candidates, we validate 60 new planets in 46 systems. These include a number of planets amenable to transmission spectroscopy (K2-384 f, K2-387 b, K2-390 b, K2-403 b, and K2-398 c), emission spectroscopy (K2-371 b, K2-370 b, and K2-399 b), and both (K2-405 b and K2-406 b); several systems with planets in or close to mean motion resonances (K2-381 and K2-398) including a compact, TRAPPIST-1-like system of five small planets orbiting a mid-M dwarf (K2-384); an ultra-short-period sub-Saturn in the hot Saturn desert (K2-399 b); and a super-Earth orbiting a moderately bright (V = 11.93), metal-poor ([Fe/H] = −0.579 ± 0.080) host star (K2-408 b). In total we validate planets around four F stars, 26 G stars, 13 K stars, and three M dwarfs. In addition, we provide a list of 37 vetted planet candidates that should be prioritized for future follow-up observation in order to be confirmed or validated.

TFAW survey II: six newly validated planets and 13 planet candidates fromK2

“…We visually inspect the transits positions in the light curves and require that they are at least 0.5 days away from the beginning or end of any gaps in their light curves to avoid false positives, especially in the case of long period candidates. 6) we cross-match our candidates with the most up-to-date (March 2022) lists of confirmed or candidate exoplanets from the NASA Exoplanet Archive 4 or in the Vizier database (Adams et al 2016;Barros et al 2016;Crossfield et al 2016;Vanderburg et al 2016;Crossfield et al 2018;Hirano et al 2018;Livingston et al 2018;Mayo et al 2018;Dattilo et al 2019;Kruse et al 2019;Castro González et al 2020;Kovacs 2020;Zink et al 2020;Adams et al 2021;Castro-González et al 2021;de Leon et al 2021;Zink et al 2021;Christiansen et al 2022). 7) we run EDI-Vetter Unplugged 5 , a simplified version of EDI-Vetter (Zink et al 2020), that uses the output from TLS to identify false-positive transit-like signals using a battery of tests: transit outliers, individual transit, even/odd transit, secondary transit, phase coverage, period and transit duration limits, period alias, and flux contamination checks.…”

“…We added a modification to the code in order to account for the aperture size used by EVEREST 2.0 as it is usually larger than the one used by the standard Kepler pipeline. We use the same threshold for the p-value as Christiansen et al (2022) to separate between false positives and possible planetary candidates. Only those candidates with 𝑝 > 0.05 are considered vetted planetary candidates.…”

“…These have provided the best photometric precision for K2 light curves and can return photometric precisions very similar to the ones from ★ E-mail: danieldelser@icc.ub.edu the original Kepler mission to K p =15 mag. Most planet searches in K2 campaigns used these EVEREST 2.0-corrected light curves, yielding an appreciable fraction of the currently confirmed planets and candidates (Mayo et al 2018;Kovacs 2020;Zink et al 2020;Adams et al 2021;de Leon et al 2021;Castro-González et al 2021;Zink et al 2021;Christiansen et al 2022). The development of new transit search tools has also helped increase the number of planets detected.…”

VaTEST III: Validation of eight potential super-earths from TESS data

“…The list of such tools contains BLENDER (Torres et al 2005), PASTIS (Díaz et al 2014), VESPA (Morton 2015), and TRICERATOPS (Giacalone & Dressing 2020;Giacalone et al 2021). VESPA and TRICERATOPS are the most commonly used tools in the Kepler and TESS era, respectively (Morton et al 2016;Giacalone et al 2021;Christiansen et al 2022;Giacalone et al 2022;Mistry et al 2023a,b). As per Morton, Giacalone, & Bryson (2023), VESPA is now retired as it is no longer maintained and has not been updated to account for the modern astronomy data landscape.…”

The Unusual M-dwarf Warm Jupiter TOI-1899 b: Refinement of Orbital and Planetary Parameters

“…With the recent abundance of space-based photometric data from the Transiting Exoplanet Survey Satellite (TESS; Ricker et al 2014), we are beginning to find more examples of these rare M-dwarf gas giants, including nine short-period Jupiters (P 10 days; see Cañas et al 2022;Gan et al 2022, and references therein). However, warm Jupiters (WJs)-here defined as gas giant planets with periods between 10 and 100 days-around M dwarfs are much rarer, with only three other examples known apart from TOI-1899 b: the two statistically validated planets Kepler-1628 b (P = 76.4 days, R p = 6.5 R ⊕ ; Morton et al 2016) and K2-387 b (P = 28.7 days, R p = 7.3 R ⊕ ; Christiansen et al 2022), and the very young TOI-1227 b (P = 27.4 days, R p = 9.6 R ⊕ ; Mann et al 2022), which is expected to contract to 5 R ⊕ as it cools. However, TOI-1899 b is the only M-dwarf WJ with a mass measurement.…”