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Stellar Activity and Exclusion of the Outer Planet in the HD 99492 System

Kane, Stephen R. and Thirumalachari, Badrinath and Henry, Gregory W. and Hinkel, Natalie R. and Jensen, Eric L. N. and Boyajian, Tabetha S. and Fischer, Debra A. and Howard, Andrew W. and Isaacson, Howard T. and Wright, Jason T. (2016) Stellar Activity and Exclusion of the Outer Planet in the HD 99492 System. Astrophysical Journal Letters, 820 (1). Art. No. L5. ISSN 2041-8213.

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A historical problem for indirect exoplanet detection has been contending with the intrinsic variability of the host star. If the variability is periodic, it can easily mimic various exoplanet signatures, such as radial velocity (RV) variations that originate with the stellar surface rather than the presence of a planet. Here we present an update for the HD 99492 planetary system, using new RV and photometric measurements from the Transit Ephemeris Refinement and Monitoring Survey. Our extended time series and subsequent analyses of the Ca ii H&K emission lines show that the host star has an activity cycle of ~13 years. The activity cycle correlates with the purported orbital period of the outer planet, the signature of which is thus likely due to the host star activity. We further include a revised Keplerian orbital solution for the remaining planet, along with a new transit ephemeris. Our transit-search observations were inconclusive.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Kane, Stephen R.0000-0002-7084-0529
Henry, Gregory W.0000-0003-4155-8513
Hinkel, Natalie R.0000-0003-0595-5132
Jensen, Eric L. N.0000-0002-4625-7333
Boyajian, Tabetha S.0000-0001-9879-9313
Fischer, Debra A.0000-0003-2221-0861
Howard, Andrew W.0000-0001-8638-0320
Isaacson, Howard T.0000-0002-0531-1073
Wright, Jason T.0000-0001-6160-5888
Additional Information:© 2016 The American Astronomical Society. Received 2016 February 19; accepted 2016 March 1; published 2016 March 14. G.W.H. acknowledges long-term support from Tennessee State University and the State of Tennessee through its Centers of Excellence 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. The results reported herein benefited from collaborations and/or information exchange within NASA's Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA's Science Mission Directorate. 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. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Funding AgencyGrant Number
Tennessee State UniversityUNSPECIFIED
State of TennesseeUNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
Subject Keywords:planetary systems – stars: individual (HD 99492) – techniques: photometric – techniques: radial velocities
Issue or Number:1
Record Number:CaltechAUTHORS:20170619-132717282
Persistent URL:
Official Citation:Stephen R. Kane et al 2016 ApJL 820 L5
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:78331
Deposited By: Tony Diaz
Deposited On:19 Jun 2017 20:40
Last Modified:09 Mar 2020 13:18

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