VALIDATION OF 12 SMALLKEPLERTRANSITING PLANETS IN THE HABITABLE ZONE

Abstract

We present an investigation of twelve candidate transiting planets from Kepler with orbital periods ranging from 34 to 207 days, selected from initial indications that they are small and potentially in the habitable zone (HZ) of their parent stars. Few of these objects are known. The expected Doppler signals are too small to confirm them by demonstrating that their masses are in the planetary regime. Here we verify their planetary nature by validating them statistically using the BLENDER technique, which simulates large numbers of false positives and compares the resulting light curves with the Kepler photometry. This analysis was supplemented with new follow-up observations (high-resolution optical and near-infrared spectroscopy, adaptive optics imaging, and speckle interferometry), as well as an analysis of the flux centroids. For eleven of them (KOI

DISCOVERY AND VALIDATION OF Kepler-452b: A 1.6R⨁SUPER EARTH EXOPLANET IN THE HABITABLE ZONE OF A G2 STAR

“…The algorithm used to generate blend light curves and compare them to the observed photometry in a 2 c sense is known as BLENDER (Torres et al 2004(Torres et al , 2011Fressin et al 2012), which has been applied in the past to the validation of many of the most interesting Kepler discoveries (see, e.g., Ballard et al 2013;Barclay et al 2013;Borucki et al 2013;Meibom et al 2013;Kipping et al 2014), including, most recently, a sample of twelve small planets in the habitable zone of their parent stars (Torres et al 2015). For full details of the technique, we refer the reader to the latter publication.…”

“…This was somewhat more conservative, as Torres et al (2015) took the inner boundary of the habitable zone to correspond to that for dry desert worlds from Zsom et al (2013), which permits habitable worlds as close as 0.38 AU from a solar-like host star if the albedo is high and the relative humidity is low (∼1%).…”

“…These discoveries include Kepler-62e and f (Borucki et al 2013), Kepler-186f (Quintana et al 2014), a few among the multitude of planets reported by Rowe et al (2014): Kepler-283c, Kepler-296e and f; and a set of small planets announced in Torres et al (2015): . The repurposed Kepler Mission, dubbed K2, has also added a small planet on the inside edge of its habitable zone: K2-3d (aka EPIC 201367065d; Crossfield et al 2015).…”

Three Statistically Validated K2 Transiting Warm Jupiter Exoplanets Confirmed as Low-mass Stars

“…Those candidates need to be examined by gathering additional data, to check whether the transit light curve is produced by a transiting star-planet system, or by a different scenario, making the object a false positive (e.g., Torres et al 2011;Fressin et al 2013). As there are insufficient observational resources needed for gathering the amount of data required to investigate the true nature of each transiting planet candidate, and because some planets cannot be confirmed with current observational capabilities, a statistical validation approach was developed (e.g., Torres et al 2011Torres et al , 2015Morton et al 2016). This approach uses a relatively small amount of observational follow-up data, typically including a single spectrum and a single high angular resolution image of the target, and is based on estimating the probability that the transit light curve is produced by a transiting star-planet system and not a false-positive scenario (e.g., Torres et al 2011;Morton 2012).…”

A detector interferometric calibration experiment for high precision astrometry

“…Another interesting trend has been the discovery of increasingly smaller planets, down to the terrestrial ones. In some specific cases, we can detect these terrestrial planets in the habitable-zones of their stars, for example with transits (Torres et al 2015) or for M stars (Bonfils et al 2013, hereafter B13).…”