A speckle-imaging search for close triple companions of cataclysmic binaries

October 2021 • 2021MNRAS.507..560S

Authors • Shara, Michael M. • Howell, Steve B. • Furlan, Elise • Gnilka, Crystal L. • Moffat, Anthony F. J. • Scott, Nicholas J. • Zurek, David

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.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2021MNRAS.507..560S
• PDF http://academic.oup.com/mnras/pdf-lookup/doi/10.1093/mnras/stab2212
• PDF https://academic.oup.com/mnras/pdf-lookup/doi/10.1093/mnras/stab2212
• PREPRINT http://arxiv.org/abs/2107.13675
• DATA https://archive.gemini.edu/searchform/publication=2021MNRAS.507..560S
• ELECTR https://doi.org/10.1093%2Fmnras%2Fstab2212