article published yes Jan Kára author Liliana Rivera Sandoval author Wendy Mendoza author Thomas Maccarone author Manuel Pichardo Marcano author Luis E. Salazar Manzano author Ryan J. Oelkers author Joannes C van Roestel author 4d122fc8-6083-11f0-87a5-97d68b860333 IlCa department AM CVn stars are ultra-compact semi-detached binaries consisting of a white dwarf primary and a hydrogen-depleted secondary. In this paper, we present spectroscopic and photometric results of 15 transient sources pre-classified as AM CVn candidates. Our analysis confirms 9 systems of the type AM CVn, 3 hydrogen-rich cataclysmic variables (accreting white dwarfs with near-main-sequence stars for donors), and 3 systems that could be evolved cataclysmic variables. Eight of the AM CVn stars are analysed spectroscopically for the first time, which increases the number of spectroscopically confirmed AM CVns by about 10%. TESS data revealed the orbital period of the AM CVn star ASASSN-20pv to be Porb =27.282 min, which helps to constrain the possible values of its mass ratio. TESS also helped to determine the superhump periods of one AM CVn star (ASASSN-19ct, Psh =30.94 min) and two cataclysmic variables we classify as WZ Sge stars (Psh =90.77 min for ZTF18aaaasnn and Psh =91.6min for ASASSN-15na).We identified very different abundances in the spectra of theAM CVns binaries ASASSN-15kf and ASASSN-20pv (both Porb ∼27.5min), suggesting different type of donors. Six of the studied AMCVns are X-ray sources, which helped to determine their mass accretion rates. Photometry shows that the duration of all the superoutbursts detected in the AM CVns is consistent with expectations from the disc instability model. Finally, we provide refined criteria for the identification of new systems using all-sky surveys such as LSST. https://research-explorer.ista.ac.at/download/21842/21862/2026_PublAstronomicalSocAustralia_Kara.pdf application/pdfno Cambridge University Press2026 eng 1323-3580 1448-608310.1017/pasa.2026.10184 43 Kára, J., Rivera Sandoval, L., Mendoza, W., Maccarone, T., Pichardo Marcano, M., Salazar Manzano, L. E., … van Roestel, J. C. (2026). A study of transients from ground-based surveys reveals new ultra-compact accreting white dwarf binaries. <i>Publications of the Astronomical Society of Australia</i>. Cambridge University Press. <a href="https://doi.org/10.1017/pasa.2026.10184">https://doi.org/10.1017/pasa.2026.10184</a> Kára J, Rivera Sandoval L, Mendoza W, Maccarone T, Pichardo Marcano M, Salazar Manzano LE, Oelkers RJ, van Roestel JC. 2026. A study of transients from ground-based surveys reveals new ultra-compact accreting white dwarf binaries. Publications of the Astronomical Society of Australia. 43, e052. J. Kára, L. Rivera Sandoval, W. Mendoza, T. Maccarone, M. Pichardo Marcano, L.E. Salazar Manzano, R.J. Oelkers, J.C. van Roestel, Publications of the Astronomical Society of Australia 43 (2026). J. Kára <i>et al.</i>, “A study of transients from ground-based surveys reveals new ultra-compact accreting white dwarf binaries,” <i>Publications of the Astronomical Society of Australia</i>, vol. 43. Cambridge University Press, 2026. Kára J, Rivera Sandoval L, Mendoza W, et al. A study of transients from ground-based surveys reveals new ultra-compact accreting white dwarf binaries. <i>Publications of the Astronomical Society of Australia</i>. 2026;43. doi:<a href="https://doi.org/10.1017/pasa.2026.10184">10.1017/pasa.2026.10184</a> Kára, Jan, et al. “A Study of Transients from Ground-Based Surveys Reveals New Ultra-Compact Accreting White Dwarf Binaries.” <i>Publications of the Astronomical Society of Australia</i>, vol. 43, e052, Cambridge University Press, 2026, doi:<a href="https://doi.org/10.1017/pasa.2026.10184">10.1017/pasa.2026.10184</a>. Kára, Jan, Liliana Rivera Sandoval, Wendy Mendoza, Thomas Maccarone, Manuel Pichardo Marcano, Luis E. Salazar Manzano, Ryan J. Oelkers, and Joannes C van Roestel. “A Study of Transients from Ground-Based Surveys Reveals New Ultra-Compact Accreting White Dwarf Binaries.” <i>Publications of the Astronomical Society of Australia</i>. Cambridge University Press, 2026. <a href="https://doi.org/10.1017/pasa.2026.10184">https://doi.org/10.1017/pasa.2026.10184</a>. 218422026-05-07T08:55:00Z2026-05-12T06:57:40Z