A Caltech Library Service

Validation of 12 Small Kepler Transiting Planets in the Habitable Zone

Torres, Guillermo and Ciardi, David R. and Howard, Andrew W. (2015) Validation of 12 Small Kepler Transiting Planets in the Habitable Zone. Astrophysical Journal, 800 (2). Art. No. 99. ISSN 0004-637X.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Submitted Version
See Usage Policy.


Use this Persistent URL to link to this item:


We present an investigation of 12 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 11 of them (KOI-0571.05, 1422.04, 1422.05, 2529.02, 3255.01, 3284.01, 4005.01, 4087.01, 4622.01, 4742.01, and 4745.01) we show that the likelihood they are true planets is far greater than that of a false positive, to a confidence level of 99.73% (3σ) or higher. For KOI-4427.01 the confidence level is about 99.2% (2.6σ). With our accurate characterization of the GKM host stars, the derived planetary radii range from 1.1 to 2.7 R_⊕. All 12 objects are confirmed to be in the HZ, and nine are small enough to be rocky. Excluding three of them that have been previously validated by others, our study doubles the number of known rocky planets in the HZ. KOI-3284.01 (Kepler-438b) and KOI-4742.01 (Kepler-442b) are the planets most similar to the Earth discovered to date when considering their size and incident flux jointly.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Torres, Guillermo0000-0002-5286-0251
Ciardi, David R.0000-0002-5741-3047
Howard, Andrew W.0000-0001-8638-0320
Additional Information:© 2015 American Astronomical Society. Received 2014 September 29; accepted 2014 December 16; published 2015 February 18. We thank the referee for helpful comments on the original manuscript. This paper includes data collected by the Kepler spacecraft. Funding for the Kepler Mission is provided by NASA’s Science Mission Directorate. The research has also made use of the Michael Dodds Computing Facility, of NASA’s Astrophysics Data System (ADS), and of data products from the Mikulski Archive for Space Telescopes (MAST). Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA. We extend special thanks to those of Hawaiian ancestry on whose sacred mountain of Mauna Kea we are privileged to be guests. G.T. acknowledges partial support for this work from NASA grant NNX14AB83G (Kepler Participating Scientist Program). D.M.K. is supported by the Harvard College Observatory Menzel Fellowship.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Harvard College Observatory Menzel FellowshipUNSPECIFIED
Subject Keywords:methods: statistical; planetary systems; stars: individual (KOI-3284 (Kepler-438), KOI-4742 (Kepler-442)); techniques: photometric
Issue or Number:2
Record Number:CaltechAUTHORS:20150323-131542155
Persistent URL:
Official Citation:Validation of 12 Small Kepler Transiting Planets in the Habitable Zone Guillermo Torres et al. 2015 ApJ 800 99
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:55974
Deposited By: Ruth Sustaita
Deposited On:23 Mar 2015 21:30
Last Modified:03 Oct 2019 08:10

Repository Staff Only: item control page