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

C. Duffy, G. Ramsay, D. Steeghs, V. Dhillon, D. Mata Sánchez, K. Ackley, M. Dyer, J. Lyman, K. Ulaczyk, D. K. Galloway, P. O'Brien, K. Noysena, L. Nuttall, D. Pollacco

Research output: Contribution to journalArticlepeer-review

90 Downloads (Pure)


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.
Original languageEnglish
Pages (from-to)4953-4962
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
Early online date11 Feb 2021
Publication statusPublished - 1 Apr 2021


  • astro-ph.SR
  • accretion
  • accretion discs
  • surveys
  • binaries: close
  • stars: dwarf novae
  • UKRI
  • STFC
  • ST/T007184/1
  • ST/T003103/1


Dive into the research topics of 'Evidence that short period AM CVn systems are diverse in outburst behaviour'. Together they form a unique fingerprint.

Cite this