Robo-AO Kepler Survey. V. The Effect of Physically Associated Stellar Companions on Planetary Systems

Creators: Ziegler, Carl; Law, Nicholas M.; Baranec, Christoph; Howard, Ward; Morton, Tim; Riddle, Reed; Duev, Dmitry A.; Salama, Maïssa; Jensen-Clem, Rebecca; Kulkarni, S. R.

Abstract

The Kepler light curves used to detect thousands of planetary candidates are susceptible to dilution due to blending with previously unknown nearby stars. With the automated laser adaptive optics instrument, Robo-AO, we have observed 620 nearby stars around 3857 planetary candidates host stars. Many of the nearby stars, however, are not bound to the KOI. We use galactic stellar models and the observed stellar density to estimate the number and properties of unbound stars. We estimate the spectral type and distance to 145 KOIs with nearby stars using multi-band observations from Robo-AO and Keck-AO. Most stars within 1'' of a Kepler planetary candidate are likely bound, in agreement with past studies. We use likely bound stars and the precise stellar parameters from the California Kepler Survey to search for correlations between stellar binarity and planetary properties. No significant difference between the binarity fraction of single and multiple-planet systems is found, and planet hosting stars follow similar binarity trends as field stars, many of which likely host their own non-aligned planets. We find that hot Jupiters are ~4× more likely than other planets to reside in a binary star system. We correct the radius estimates of the planet candidates in characterized systems and find that for likely bound systems, the estimated planetary radii will increase on average by a factor of 1.77, if either star is equally likely to host the planet. Lastly, we find the planetary radius gap is robust to the impact of dilution.

Additional Information

© 2018 The American Astronomical Society. Received 2018 April 26; revised 2018 June 5; accepted 2018 June 15; published 2018 August 3. We thank the anonymous referee for careful analysis and useful comments on the manuscript. This research is supported by the NASA Exoplanets Research Program, grant #NNX 15AC91G. C.Z. and W.H. acknowledge support from the North Carolina Space Grant consortium. C.B. acknowledges support from the Alfred P. Sloan Foundation. T.M. is supported by NASA grant #NNX 14AE11G under the Kepler Participating Scientist Program. We thank the observatory staff at Kitt Peak for their efforts to assist Robo-AO KP operations and are grateful to the Palomar Observatory staff for their support of Robo-AO on the 1.5 m telescope. The Robo-AO instrument was developed with support from the National Science Foundation under grants AST-0906060, AST-0960343, and AST-1207891, IUCAA, the Mt. Cuba Astronomical Foundation, and by a gift from Samuel Oschin. The Robo-AO team thanks NSF and NOAO for making the Kitt Peak 2.1 m telescope available. Robo-AO KP is a partnership between the California Institute of Technology, the University of Hawaii, the University of North Carolina at Chapel Hill, the Inter-University Centre for Astronomy and Astrophysics (IUCAA) at Pune, India, and the National Central University, Taiwan. The Murty family feels very happy to have added a small value to this important project. Robo-AO KP is also supported by grants from the John Templeton Foundation and the Mt. Cuba Astronomical Foundation. Some data are based on observations at Kitt Peak National Observatory, National Optical Astronomy Observatory (NOAO Prop. ID: 15B-3001), which is operated by the Association of Universities for Research in Astronomy (AURA) under cooperative agreement with the National Science Foundation. 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 the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. We recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Facilities: PO:1.5m (Robo-AO) - , KPNO:2.1m (Robo-AO) - , Keck:II (NIRC2-LGS) - KECK II Telescope.

Attached Files

Published - Ziegler_2018_AJ_156_83.pdf

Submitted - 1804.10208.pdf

Files

Ziegler_2018_AJ_156_83.pdf

Files (7.0 MB)

Name	Size	Download all
Ziegler_2018_AJ_156_83.pdf md5:4389c45c8c58bdb0332898da801a7b01	2.3 MB	Preview Download
1804.10208.pdf md5:4e4f4d2dad6f02eb62b2dd6d72ed7291	4.7 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes