The California-Kepler Survey. I. High-resolution Spectroscopy of 1305 Stars Hosting Kepler Transiting Planets^*

Abstract

The California-Kepler Survey (CKS) is an observational program developed to improve our knowledge of the properties of stars found to host transiting planets by NASA's Kepler Mission. The improvement stems from new high-resolution optical spectra obtained using HIRES at the W. M. Keck Observatory. The CKS stellar sample comprises 1305 stars classified as Kepler objects of interest, hosting a total of 2075 transiting planets. The primary sample is magnitude-limited ( < Kp 14.2) and contains 960 stars with 1385 planets. The sample was extended to include some fainter stars that host multiple planets, ultra-short period planets, or habitable zone planets. The spectroscopic parameters were determined with two different codes, one based on template matching and the other on direct spectral synthesis using radiative transfer. We demonstrate a precision of 60K in T eff , 0.10dex in g log , 0.04dex in [ ] Fe H , and 1.0 -km s 1 in V i sin . In this paper, we describe the CKS project and present a uniform catalog of spectroscopic parameters. Subsequent papers in this series present catalogs of derived stellar properties such as mass, radius, and age; revised planet properties; and statistical explorations of the ensemble. CKS is the largest survey to determine the properties of Kepler stars using a uniform set of high-resolution, high signal-tonoise ratio spectra. The HIRES spectra are available to the community for independent analyses.

Planetary Candidates Observed by Kepler. VIII. A Fully Automated Catalog with Measured Completeness and Reliability Based on Data Release 25

“…Therefore, planets are more common than stars in the Galaxy (due, in part, to the fact that low-mass stars are the most common stellar type). Fulton et al (2017), using improved measurements of the stellar properties (Petigura et al 2017a), looked at small planets with periods of less than 100 days and showed that there is a valley in the occurrence of planets near 1.75 R ⊕ . This result improved on the results of Howard et al (2012) and Lundkvist et al (2016) and further verified the evaporation valley predicted by Owen & Wu (2013) and Lopez & Fortney (2013) for close-in planets.…”

Identifying Exoplanets with Deep Learning: A Five-planet Resonant Chain around Kepler-80 and an Eighth Planet around Kepler-90

“…Therefore, Kepler-90i is likely slightly inclined away from our line of sight. If the orbit of Kepler-90i is perfectly Petigura et al (2017) and Johnson et al (2017). Equilibrium temperatures are calculated assuming perfect heat redistribution and albedos uniformly distributed between 0 and 0.7. circular, its impact parameter would have to be about 0.85; this gives it an orbital inclination of about 88°, compared to the other seven planets in the system, which all likely have orbital inclinations of 89°or higher.…”

“…We used our constraints from the image centroid analysis to specify the s 3 maximum radius at which a contaminating star could contribute the transit signal. We used the spectroscopic parameters from MacDonald et al (2016) and Petigura et al (2017) as inputs for Kepler-80 and Kepler-90, respectively, and we included near-infrared photometry from the 2MASS survey (Skrutskie et al 2006). Recently, it has been shown that systematic photometric uncertainties and/or offsets between photometric data sets can cause vespa to misclassify planet candidates (Shporer et al 2017;Mayo et al 2017, in preparation), so we avoided this issue by only including the high-quality 2MASS photometry.…”

Seeing Double with K2: Testing Re-inflation with Two Remarkably Similar Planets around Red Giant Branch Stars

“…HIRES provides a spectral resolution of roughly 65,000 in the wavelength range of 4500-6200 Å (Vogt et al 1994) and has been used to both characterize over 1000 Kepler planet host stars as well as confirm and provide precise parameters of over 2000 Kepler planets Johnson et al 2017). Our spectra were analyzed using the software package SpecMatch (Petigura 2015) following the procedure outlined in G16.…”