Evidence that short period AM CVn systems are diverse in outburst behaviour

Abstract

We present results of our analysis of up to 15 years of photometric data from eight AM CVn systems with orbital periods between 22.5 and 26.8 min. Our data has been collected from the GOTO, ZTF, Pan-STARRS, ASAS-SN and Catalina all-sky surveys and amateur observations collated by the AAVSO. We find evidence that these interacting ultra-compact binaries show a similar diversity of long term optical properties as the hydrogen accreting dwarf novae. We found that AM CVn systems in the previously identified accretion disc instability region are not a homogenous group. Various members of the analysed sample exhibit behaviour reminiscent of Z Cam systems with long super outbursts and standstills, SU UMa systems with regular, shorter super outbursts, and nova-like systems which appear only in a high state. The addition of TESS full frame images of one of these systems, KL Dra, reveals the first evidence for normal outbursts appearing as a precursor to super outbursts in an AM CVn system. Our results will inform theoretical modelling of the outbursts of hydrogen deficient systems.

11 Pages, 7 Figures, 2 Tables. Accepted for publication in MNRAS. Author's final submitted version

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Cited by in corpus (13)

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• A Systematic Search for Short-period Close White Dwarf Binary Candidates Based on Gaia EDR3 Catalog and Zwicky Transient Facility Data
• A systematic search for outbursting AM CVn systems with the Zwicky Transient Facility
• TACOS: TESS AM~CVn Outbursts Survey
• Orbital decay in an accreting and eclipsing 13.7 minute orbital period binary with a luminous donor
• A Catalogue of Ultracompact Mass-Transferring White Dwarf Binaries
• New Candidates for AM Canum Venaticorum Stars among ASAS-SN Transients
• The Fast Evolving, Tremendous and Blue Superoutburst in ASASSN-21au Reveals a Dichotomy in the Outbursts of Long-period AM CVns
• The Gravitational-wave Optical Transient Observer (GOTO)
• TCP J07222683$+$6220548: a new AM CVn type system with infrequent outbursts
• The Gravitational-wave Optical Transient Observer (GOTO): prototype performance and prospects for transient science
• Machine Learning applications for Cataclysmic Variable discovery in the ZTF alert stream
• Recent humps and superhumps observations and an estimation of outburst parameters of the AM CVn star CR Boo