A speckle-imaging search for close triple companions of cataclysmic binaries
Abstract
The orbital periods of most eclipsing cataclysmic binaries are not undergoing linear secular decreases of order a few parts per billion as expected from simple theory. Instead, they show several parts per million increases and decreases on time-scales of years to decades, ascribed to magnetic effects in their donors, triple companions, or both. To directly test the triple companion hypothesis, we carried out a speckle-imaging survey of six of the nearest and brightest cataclysmic variables. We found no main-sequence companions earlier than spectral types M4V in the separation range ∼0.02–1.2 arcsec, corresponding to projected linear separations of ∼2–100 au, and periods of ∼3–1000 yr. We conclude that main-sequence triple companions to cataclysmic variables are not very common, but cannot rule out the presence of the faintest M dwarfs or close brown dwarf companions.
Additional Information
© 2021 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2021 July 28. Received 2021 July 28; in original form 2021 May 7. Published: 05 August 2021. The data presented in this paper are based on observations obtained at the international Gemini Observatory, a program of NSF's NOIRLab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation on behalf of the Gemini Observatory partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciéncia, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). This work was enabled by observations made from the Gemini North telescope, located within the Maunakea Science Reserve and adjacent to the summit of Maunakea. We are grateful for the privilege of observing the Universe from a place that is unique in both its astronomical quality and its cultural significance. Observations in the paper made use of the high-resolution imaging instruments Zorro and 'Alopeke, which were funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. Zorro was mounted on the Gemini South telescope, and 'Alopeke on the Gemini North telescope of the international Gemini Observatory. We thank the Canadian Gemini Time Allocation Committee for excellent feedback and support, and their allocation of telescope time. The observations were obtained under Gemini proposal GN-2020A-Q-110. MMS thanks Nathan Leigh and Silvia Toonen for stimulating conversations about the likelihood and origins of triple companions to CVs. We acknowledge helpful suggestions from the referee which improved an earlier version of this paper. Data Availability Statement: The data underlying this article will be shared on reasonable request to the corresponding author. The raw speckle data are also available on the Gemini archive.Attached Files
Published - stab2212.pdf
Accepted Version - 2107.13675.pdf
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- CaltechAUTHORS:20211019-190552955
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2021-10-20Created from EPrint's datestamp field
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2021-10-21Created from EPrint's last_modified field
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- Infrared Processing and Analysis Center (IPAC)