A Catalogue of All Known Mass-Transferring Ultracompact Binary Systems

Introduction: I present a catalogue that collects all known mass-transferring ultracompact binary systems in one place. This includes AM CVn-type binaries, helium-enriched CVs and a variety of other objects. The goal of this catalogue is to prevent the duplicated effort of multiple researchers searching for known systems through the literature. Where applicable, the catalogue includes orbital periods, measured masses, Gaia cross-matches, as well as important references for each system. The catalogue includes 'confirmed' systems (usually means an orbital period measurement and/or a spectrum) and 'candidates' (may be selected based on other properties such as outburst shape). For full details and references see the associated paper (accepted to A&A). Preprint at https://arxiv.org/abs/2505.10535 See the catalogue itself in the file 'amcvn_catalogue.fits'. New to version 2026.03.01: Up to date as of 2026-03-01 Typo fixes to ZTF J0407 (declination) and SRGe J0403 (period) Added Gaia crossmatch for ASASSN-19ct Added columns: BPRP error and Gaia crossmatch distance