@article{be59347a81d14ba4abe8f3926cd34923,
title = "The hierarchical triple nature of the former red nova precursor candidate KIC 9832227",
abstract = "We revisit the issue of period variation of the recently claimed red nova precursor candidate KIC 9832227. By using the data gathered during the main mission of the Kepler satellite, and data collected by ground-based wide-field surveys and other monitoring programs (such as ASAS-SN), we find that the currently available timing data strongly support a model consisting of the known W UMa binary and a distant low-mass companion with an orbital period of ∼13.5 years. The period of the W UMa component exhibits a linear period decrease at a rate of (1.10 ± 0.05) × 10-6 days per year, within the range of many other similar systems. This rate of decrease is several orders of magnitude lower than that of V1309 Sco, the first (and so far the only) well-established binary precursor of a nova observed a few years before the outburst. The high-fidelity fit of the timing data and the conformity of the derived minimum mass of (0.38 ± 0.02) Mpdbl of the outer companion from these data with the limit posed by the spectroscopic non-detection of this component are in agreement with the suggested hierarchical nature of this system.",
keywords = "Binaries: eclipsing, Binaries: general, Binaries: spectroscopic, Stars: individual: KIC 9832227, Stars: variables: general",
author = "Geza Kovacs and Hartman, {Joel D.} and G{\'a}sp{\'a}r Bakos",
note = "Funding Information: Acknowledgements. We thank Sebastian Otero at AAVSO for answering our questions on various aspects of the data accessed. We are grateful to the observers listed in Appendix A of this paper for their valuable contribution via the AAVSO database. We acknowledge the improvement in the model fit by following the suggestion of the referee of using uniform timebase (i.e., BJD) for all data. Thanks are due also to Yakiv Pavlenko, for the correspondence on the analysis of the NIR spectra. This research has made use of the International Variable Star Index (VSX) database operated at AAVSO, Cambridge, Massachusetts, USA. This paper includes data collected by the Kepler mission. Funding for the Kepler mission is provided by the NASA Science Mission directorate. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. The NSVS data have been downloaded from the site of SkyDOT, operated by the University of California for the National Nuclear Security Administration of the US Department of Energy. This research has made use of the VizieR catalogue access tool, CDS, Strasbourg, France (DOI: 10.26093/cds/vizier). Support from the National Research, Development and Innovation Office (grants K 129249 and NN 129075) are acknowledged. Data presented in this paper are based on observations obtained by the HAT station at the Submillimeter Array of SAO, and the HAT station at the Fred Lawrence Whipple Observatory of SAO. HATNet observations have been funded by NASA grants NNG04GN74G and NNX13AJ15G. Publisher Copyright: {\textcopyright} ESO 2019.",
year = "2019",
month = nov,
day = "1",
doi = "10.1051/0004-6361/201936207",
language = "English (US)",
volume = "631",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",
}