[{"year":"2026","ddc":["520"],"_id":"21160","day":"01","arxiv":1,"OA_type":"diamond","quality_controlled":"1","scopus_import":"1","department":[{"_id":"IlCa"}],"publication_status":"published","file_date_updated":"2026-02-16T09:33:56Z","volume":706,"oa_version":"Published Version","has_accepted_license":"1","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","author":[{"full_name":"Yu, W.","first_name":"W.","last_name":"Yu"},{"full_name":"Pala, A. F.","last_name":"Pala","first_name":"A. F."},{"full_name":"Kupfer, T.","first_name":"T.","last_name":"Kupfer"},{"full_name":"Gänsicke, B. T.","last_name":"Gänsicke","first_name":"B. T."},{"full_name":"Koester, D.","last_name":"Koester","first_name":"D."},{"full_name":"Belloni, D.","last_name":"Belloni","first_name":"D."},{"full_name":"Wong, T. L.S.","first_name":"T. L.S.","last_name":"Wong"},{"last_name":"Schreiber","first_name":"M. R.","full_name":"Schreiber, M. R."},{"first_name":"Joannes C","last_name":"van Roestel","id":"4d122fc8-6083-11f0-87a5-97d68b860333","full_name":"van Roestel, Joannes C"},{"full_name":"Brown, A. J.","first_name":"A. J.","last_name":"Brown"},{"first_name":"E. O.","last_name":"Waagen","full_name":"Waagen, E. O."},{"first_name":"J. L.","last_name":"González-Carballo","full_name":"González-Carballo, J. L."},{"first_name":"S.","last_name":"Bednarz","full_name":"Bednarz, S."},{"first_name":"K.","last_name":"Bernacki","full_name":"Bernacki, K."},{"last_name":"De Martino","first_name":"D.","full_name":"De Martino, D."},{"last_name":"Fernández Mañanes","first_name":"E.","full_name":"Fernández Mañanes, E."},{"full_name":"González Farfán, R.","first_name":"R.","last_name":"González Farfán"},{"first_name":"M. J.","last_name":"Green","full_name":"Green, M. J."},{"first_name":"P. J.","last_name":"Groot","full_name":"Groot, P. J."},{"full_name":"Hambsch, F. J.","last_name":"Hambsch","first_name":"F. J."},{"first_name":"C.","last_name":"Knigge","full_name":"Knigge, C."},{"last_name":"Martin-Velasco","first_name":"J. L.","full_name":"Martin-Velasco, J. L."},{"first_name":"M.","last_name":"Morales-Aimar","full_name":"Morales-Aimar, M."},{"full_name":"Myers, G.","first_name":"G.","last_name":"Myers"},{"last_name":"Naves Nogues","first_name":"R.","full_name":"Naves Nogues, R."},{"last_name":"Poggiani","first_name":"R.","full_name":"Poggiani, R."},{"full_name":"Popowicz, A.","last_name":"Popowicz","first_name":"A."},{"full_name":"Ramsay, G.","last_name":"Ramsay","first_name":"G."},{"full_name":"Reina-Lorenz, E.","first_name":"E.","last_name":"Reina-Lorenz"},{"first_name":"P.","last_name":"Rodríguez-Gil","full_name":"Rodríguez-Gil, P."},{"last_name":"Salto-González","first_name":"J. L.","full_name":"Salto-González, J. L."},{"full_name":"Sion, E. M.","last_name":"Sion","first_name":"E. M."},{"full_name":"Steeghs, D.","last_name":"Steeghs","first_name":"D."},{"last_name":"Szkody","first_name":"P.","full_name":"Szkody, P."},{"full_name":"Toloza, O.","first_name":"O.","last_name":"Toloza"},{"first_name":"G.","last_name":"Tovmassian","full_name":"Tovmassian, G."}],"file":[{"content_type":"application/pdf","access_level":"open_access","date_created":"2026-02-16T09:33:56Z","file_name":"2026_AstronomyAstrophysics_Yu.pdf","creator":"dernst","file_size":4020466,"checksum":"2faec710fd04f927aa43deb57e35c9b2","relation":"main_file","file_id":"21227","date_updated":"2026-02-16T09:33:56Z","success":1}],"article_type":"original","intvolume":"       706","license":"https://creativecommons.org/licenses/by/4.0/","date_created":"2026-02-08T23:02:49Z","external_id":{"arxiv":["2512.04147"]},"status":"public","PlanS_conform":"1","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","short":"CC BY (4.0)"},"doi":"10.1051/0004-6361/202557568","article_processing_charge":"No","publication_identifier":{"eissn":["1432-0746"],"issn":["0004-6361"]},"OA_place":"publisher","publisher":"EDP Sciences","type":"journal_article","title":"The evolutionary history of ultra-compact accreting binaries: I. Chemical abundances and the formation channel of the eclipsing AM CVn system ZTF J225237.05-051917.4 from HST spectroscopy","acknowledgement":"We thank Lars Bildsten for valuable insights and discussions. We acknowledge with thanks the variable star observations from the\r\nAAVSO International Database contributed by observers worldwide and used in this research. We thank the members of the Spanish Observers of Supernovae\r\n(ObSN) group for their valuable photometric contributions. This research was\r\nsupported by Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy – EXC 2121 “Quantum Universe”\r\n– 390833306. Co-funded by the European Union (ERC, CompactBINARIES,\r\n101078773). Views and opinions expressed are however those of the author(s)\r\nonly and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority\r\ncan be held responsible for them. DB acknowledges support from the São Paulo\r\nResearch Foundation (FAPESP), Brazil, Process Numbers #2024/03736-2 and\r\n#2025/00817-4. MRS is supported by Fondecyt (grant 1221059). MJG acknowledges support from the European Research Council through ERC Advanced\r\nGrant No. 101054731, from the National Aeronautics and Space Administration under grants 80NSSC24K0436, 80NSSC22K0479, and 80NSSC24K0380,\r\nand from the National Science Foundation under grant AST-2205736. PJG\r\nis supported by NRF SARChI grant 111692. PR-G acknowledges support by\r\nthe Agencia Estatal de Investigación del Ministerio de Ciencia e Innovación\r\n(MCIN/AEI) and the European Regional Development Fund (ERDF) under grant\r\nPID2021–124879NB–I00. DS is supported by the UK Science and Technology Facilities Council (STFC, grant numbers ST/T007184/1, ST/T003103/1,\r\nand ST/T000406/1). OT acknowledges Proyectos Internos USM 2025, PI-LII2025-03. GT was supported by grants IN109723 from the Programa de Apoyo a\r\nProyectos de Investigación e Innovación Tecnológica (PAPIIT). This project has\r\nreceived funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No. 101020057).","language":[{"iso":"eng"}],"abstract":[{"text":"Context. AM Canum Venaticorum (AM CVn) stars are ultra-compact binary systems composed of a white dwarf primary accreting from a hydrogen-deficient donor. They play a crucial role in astrophysics as potential progenitors of Type Ia supernovae and as laboratories for gravitational wave studies. However, their formation and evolutionary history remain incomplete. Three formation channels have been discussed in the literature: the white dwarf, He-star, and cataclysmic variable channels.\r\n\r\nAims. The chemical composition of the accretor atmosphere reflects the material transferred from the donor. In this work we took the first accurate measurements of the fundamental parameters of the accreting white dwarf in ZTF J225237.05−051917.4, including the abundances of key elements such as carbon, nitrogen, and silicon, by analysing ultraviolet spectra obtained with the Hubble Space Telescope (HST). These measurements provide new insight into the evolutionary history of the system and, together with existing optical observations, establish it as a benchmark to develop our pipeline, paving the way for its application to a larger sample of AM CVn systems.\r\n\r\nMethods. We determined the binary parameters through photometric analysis and constrained the atmospheric parameters of the white dwarf accretor, including its effective temperature, surface gravity, and chemical abundances, by fitting the HST ultraviolet spectrum with synthetic spectral models. We then inferred the system’s formation channel by comparing the results with theoretical evolutionary models.\r\n\r\nResults. According to our measurements, the accretor’s effective temperature (Teff) is 23 300 ± 600 K and the surface gravity (log g) is 8.4 ± 0.3, which imply an accretor mass (MWD) of 0.86 ± 0.16 M⊙. We find a high nitrogen-to-carbon abundance ratio by mass of > 153.\r\n\r\nConclusions. The accretor is significantly hotter than previous estimates based on simplified blackbody fits to the spectral energy distribution, underscoring the importance of detailed spectral modelling for accurately determining system parameters. Our results show that ultraviolet spectroscopy is well suited to constraining the formation channels of AM CVn systems. Of the three proposed formation channels, the He-star channel can be excluded given the high nitrogen-to-carbon ratio. Our results are consistent with both the white dwarf and cataclysmic variable channels.","lang":"eng"}],"oa":1,"citation":{"mla":"Yu, W., et al. “The Evolutionary History of Ultra-Compact Accreting Binaries: I. Chemical Abundances and the Formation Channel of the Eclipsing AM CVn System ZTF J225237.05-051917.4 from HST Spectroscopy.” <i>Astronomy and Astrophysics</i>, vol. 706, A14, EDP Sciences, 2026, doi:<a href=\"https://doi.org/10.1051/0004-6361/202557568\">10.1051/0004-6361/202557568</a>.","apa":"Yu, W., Pala, A. F., Kupfer, T., Gänsicke, B. T., Koester, D., Belloni, D., … Tovmassian, G. (2026). The evolutionary history of ultra-compact accreting binaries: I. Chemical abundances and the formation channel of the eclipsing AM CVn system ZTF J225237.05-051917.4 from HST spectroscopy. <i>Astronomy and Astrophysics</i>. EDP Sciences. <a href=\"https://doi.org/10.1051/0004-6361/202557568\">https://doi.org/10.1051/0004-6361/202557568</a>","short":"W. Yu, A.F. Pala, T. Kupfer, B.T. Gänsicke, D. Koester, D. Belloni, T.L.S. Wong, M.R. Schreiber, J.C. van Roestel, A.J. Brown, E.O. Waagen, J.L. González-Carballo, S. Bednarz, K. Bernacki, D. De Martino, E. Fernández Mañanes, R. González Farfán, M.J. Green, P.J. Groot, F.J. Hambsch, C. Knigge, J.L. Martin-Velasco, M. Morales-Aimar, G. Myers, R. Naves Nogues, R. Poggiani, A. Popowicz, G. Ramsay, E. Reina-Lorenz, P. Rodríguez-Gil, J.L. Salto-González, E.M. Sion, D. Steeghs, P. Szkody, O. Toloza, G. Tovmassian, Astronomy and Astrophysics 706 (2026).","ama":"Yu W, Pala AF, Kupfer T, et al. The evolutionary history of ultra-compact accreting binaries: I. Chemical abundances and the formation channel of the eclipsing AM CVn system ZTF J225237.05-051917.4 from HST spectroscopy. <i>Astronomy and Astrophysics</i>. 2026;706. doi:<a href=\"https://doi.org/10.1051/0004-6361/202557568\">10.1051/0004-6361/202557568</a>","ieee":"W. Yu <i>et al.</i>, “The evolutionary history of ultra-compact accreting binaries: I. Chemical abundances and the formation channel of the eclipsing AM CVn system ZTF J225237.05-051917.4 from HST spectroscopy,” <i>Astronomy and Astrophysics</i>, vol. 706. EDP Sciences, 2026.","ista":"Yu W, Pala AF, Kupfer T, Gänsicke BT, Koester D, Belloni D, Wong TLS, Schreiber MR, van Roestel JC, Brown AJ, Waagen EO, González-Carballo JL, Bednarz S, Bernacki K, De Martino D, Fernández Mañanes E, González Farfán R, Green MJ, Groot PJ, Hambsch FJ, Knigge C, Martin-Velasco JL, Morales-Aimar M, Myers G, Naves Nogues R, Poggiani R, Popowicz A, Ramsay G, Reina-Lorenz E, Rodríguez-Gil P, Salto-González JL, Sion EM, Steeghs D, Szkody P, Toloza O, Tovmassian G. 2026. The evolutionary history of ultra-compact accreting binaries: I. Chemical abundances and the formation channel of the eclipsing AM CVn system ZTF J225237.05-051917.4 from HST spectroscopy. Astronomy and Astrophysics. 706, A14.","chicago":"Yu, W., A. F. Pala, T. Kupfer, B. T. Gänsicke, D. Koester, D. Belloni, T. L.S. Wong, et al. “The Evolutionary History of Ultra-Compact Accreting Binaries: I. Chemical Abundances and the Formation Channel of the Eclipsing AM CVn System ZTF J225237.05-051917.4 from HST Spectroscopy.” <i>Astronomy and Astrophysics</i>. EDP Sciences, 2026. <a href=\"https://doi.org/10.1051/0004-6361/202557568\">https://doi.org/10.1051/0004-6361/202557568</a>."},"date_updated":"2026-02-16T09:36:24Z","date_published":"2026-02-01T00:00:00Z","article_number":"A14","month":"02","publication":"Astronomy and Astrophysics"},{"_id":"21705","year":"2026","ddc":["520"],"arxiv":1,"day":"01","OA_type":"gold","quality_controlled":"1","department":[{"_id":"IlCa"}],"scopus_import":"1","publication_status":"published","file_date_updated":"2026-05-04T06:36:00Z","file":[{"success":1,"file_id":"21782","date_updated":"2026-05-04T06:36:00Z","relation":"main_file","checksum":"c8f64a78f36224d8e0ea1f324e43e389","file_size":1225916,"creator":"dernst","file_name":"2026_AstrophysicalJournal_Chickles.pdf","date_created":"2026-05-04T06:36:00Z","access_level":"open_access","content_type":"application/pdf"}],"volume":1000,"has_accepted_license":"1","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","oa_version":"Published Version","author":[{"full_name":"Chickles, Emma T.","last_name":"Chickles","first_name":"Emma T."},{"last_name":"Chakraborty","first_name":"Joheen","full_name":"Chakraborty, Joheen"},{"last_name":"Burdge","first_name":"Kevin B.","full_name":"Burdge, Kevin B."},{"first_name":"Vik S.","last_name":"Dhillon","full_name":"Dhillon, Vik S."},{"last_name":"Draghis","first_name":"Paul","full_name":"Draghis, Paul"},{"last_name":"El-Badry","first_name":"Kareem","full_name":"El-Badry, Kareem"},{"last_name":"Green","first_name":"Matthew J.","full_name":"Green, Matthew J."},{"first_name":"Aaron","last_name":"Householder","full_name":"Householder, Aaron"},{"full_name":"Hughes, Sarah","first_name":"Sarah","last_name":"Hughes"},{"last_name":"Layden","first_name":"Christopher","full_name":"Layden, Christopher"},{"full_name":"Littlefair, Stuart P.","last_name":"Littlefair","first_name":"Stuart P."},{"first_name":"James","last_name":"Munday","full_name":"Munday, James"},{"full_name":"Pelisoli, Ingrid","first_name":"Ingrid","last_name":"Pelisoli"},{"first_name":"Maya S.","last_name":"Redden","full_name":"Redden, Maya S."},{"last_name":"Tonry","first_name":"John","full_name":"Tonry, John"},{"last_name":"van Roestel","first_name":"Joannes C","id":"4d122fc8-6083-11f0-87a5-97d68b860333","full_name":"van Roestel, Joannes C"},{"full_name":"Angile, Francesco Elio","last_name":"Angile","first_name":"Francesco Elio"},{"last_name":"Brown","first_name":"Alex J.","full_name":"Brown, Alex J."},{"first_name":"Noel Castro","last_name":"Segura","full_name":"Segura, Noel Castro"},{"first_name":"Jack","last_name":"Dinsmore","full_name":"Dinsmore, Jack"},{"full_name":"Dyer, Martin","first_name":"Martin","last_name":"Dyer"},{"last_name":"Furesz","first_name":"Gabor","full_name":"Furesz, Gabor"},{"full_name":"Gabutti, Michelle","last_name":"Gabutti","first_name":"Michelle"},{"last_name":"Garbutt","first_name":"James","full_name":"Garbutt, James"},{"full_name":"García-Mejía, Juliana","first_name":"Juliana","last_name":"García-Mejía"},{"last_name":"Jarvis","first_name":"Daniel","full_name":"Jarvis, Daniel"},{"full_name":"Kennedy, Mark R.","last_name":"Kennedy","first_name":"Mark R."},{"last_name":"Kerry","first_name":"Paul","full_name":"Kerry, Paul"},{"full_name":"Mccormac, James","first_name":"James","last_name":"Mccormac"},{"last_name":"Mo","first_name":"Geoffrey","full_name":"Mo, Geoffrey"},{"full_name":"Osip, Dave","first_name":"Dave","last_name":"Osip"},{"first_name":"Steven","last_name":"Parsons","full_name":"Parsons, Steven"},{"full_name":"Pike, Eleanor","last_name":"Pike","first_name":"Eleanor"},{"first_name":"John J.","last_name":"Piotrowski","full_name":"Piotrowski, John J."},{"first_name":"Roger W.","last_name":"Romani","full_name":"Romani, Roger W."},{"first_name":"David","last_name":"Sahman","full_name":"Sahman, David"},{"full_name":"Simcoe, Rob","last_name":"Simcoe","first_name":"Rob"}],"article_type":"original","intvolume":"      1000","external_id":{"arxiv":["2601.07925"]},"date_created":"2026-04-12T22:01:47Z","status":"public","publication_identifier":{"eissn":["1538-4357"],"issn":["0004-637X"]},"article_processing_charge":"Yes","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","short":"CC BY (4.0)"},"doi":"10.3847/1538-4357/ae4871","type":"journal_article","OA_place":"publisher","publisher":"IOP Publishing","DOAJ_listed":"1","acknowledgement":"This work has made use of data from the Asteroid Terrestrial-impact Last Alert System (ATLAS) project. The Asteroid Terrestrial-impact Last Alert System (ATLAS) project is primarily funded to search for near-Earth asteroids through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; byproducts of the NEO search include images and catalogs from the survey area. This work was partially funded by Kepler/K2 grant J1944/80NSSC19K0112 and HST GO-15889 and STFC grants ST/T000198/1 and ST/S006109/1. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen’s University Belfast, the Space Telescope Science Institute, the South African Astronomical Observatory, and the Millennium Institute of Astrophysics (MAS), Chile. VSD and ULTRACAM are supported by STFC grant ST/Z000033/1. J.G.M. gratefully acknowledges support from the Heising-Simons Foundation and the Pappalardo family through the MIT Pappalardo Fellowship in Physics.","language":[{"iso":"eng"}],"issue":"2","title":"An eclipsing 8.56 minutes orbital period mass-transferring binary","date_updated":"2026-05-04T06:37:12Z","date_published":"2026-04-01T00:00:00Z","article_number":"237","month":"04","abstract":[{"text":"We report the discovery of ATLAS J101342.5−451656.8 (hereafter ATLAS J1013−4516), an 8.56 minute orbital-period mass-transferring AM Canum Venaticorum (AM CVn) binary with a mean Gaia magnitude of G = 19.51, identified via periodic variability in light curves from the Asteroid Terrestrial-impact Last Alert System (ATLAS) of Gaia white dwarf candidates. Follow-up with the Large Lenslet Array Magellan Spectrograph shows a helium-dominated accretion disk, and high-speed ULTRACAM photometry reveals pronounced primary and secondary eclipses. We construct a decade-long timing baseline leveraging light curves from the ATLAS and Gaia surveys, as well as the high-speed imagers ULTRACAM on the New Energy Telescope and proto-Lightspeed on the Magellan Clay telescope. From this timing baseline, we measure an orbital period derivative of P 1.60 0.07 10 = ± × 12 s s−1. Interpreted in the context of stable mass transfer, the magnitude and sign of P indicate that the orbital evolution is governed by the interplay between gravitationalwave-driven angular-momentum losses and mass transfer, directly probing the donor’s structural response to mass loss. We constrain the accretor and donor mass based on stable mass-transfer arguments assuming angularmomentum loss dominated by gravitational-wave emission, allowing us to infer the characteristic gravitational\r\nwave strain of the binary for future space-based GW observatories such as the Laser Interferometer Space Antenna (LISA). We predict a characteristic strain corresponding to a 4 yr LISA signal-to-noise ratio ≳10, establishing ATLAS J1013−4516 as a strong prospective LISA source that will probe long-term orbital evolution in the mass-transferring regime.","lang":"eng"}],"citation":{"ieee":"E. T. Chickles <i>et al.</i>, “An eclipsing 8.56 minutes orbital period mass-transferring binary,” <i>The Astrophysical Journal</i>, vol. 1000, no. 2. IOP Publishing, 2026.","short":"E.T. Chickles, J. Chakraborty, K.B. Burdge, V.S. Dhillon, P. Draghis, K. El-Badry, M.J. Green, A. Householder, S. Hughes, C. Layden, S.P. Littlefair, J. Munday, I. Pelisoli, M.S. Redden, J. Tonry, J.C. van Roestel, F.E. Angile, A.J. Brown, N.C. Segura, J. Dinsmore, M. Dyer, G. Furesz, M. Gabutti, J. Garbutt, J. García-Mejía, D. Jarvis, M.R. Kennedy, P. Kerry, J. Mccormac, G. Mo, D. Osip, S. Parsons, E. Pike, J.J. Piotrowski, R.W. Romani, D. Sahman, R. Simcoe, The Astrophysical Journal 1000 (2026).","ama":"Chickles ET, Chakraborty J, Burdge KB, et al. An eclipsing 8.56 minutes orbital period mass-transferring binary. <i>The Astrophysical Journal</i>. 2026;1000(2). doi:<a href=\"https://doi.org/10.3847/1538-4357/ae4871\">10.3847/1538-4357/ae4871</a>","chicago":"Chickles, Emma T., Joheen Chakraborty, Kevin B. Burdge, Vik S. Dhillon, Paul Draghis, Kareem El-Badry, Matthew J. Green, et al. “An Eclipsing 8.56 Minutes Orbital Period Mass-Transferring Binary.” <i>The Astrophysical Journal</i>. IOP Publishing, 2026. <a href=\"https://doi.org/10.3847/1538-4357/ae4871\">https://doi.org/10.3847/1538-4357/ae4871</a>.","ista":"Chickles ET, Chakraborty J, Burdge KB, Dhillon VS, Draghis P, El-Badry K, Green MJ, Householder A, Hughes S, Layden C, Littlefair SP, Munday J, Pelisoli I, Redden MS, Tonry J, van Roestel JC, Angile FE, Brown AJ, Segura NC, Dinsmore J, Dyer M, Furesz G, Gabutti M, Garbutt J, García-Mejía J, Jarvis D, Kennedy MR, Kerry P, Mccormac J, Mo G, Osip D, Parsons S, Pike E, Piotrowski JJ, Romani RW, Sahman D, Simcoe R. 2026. An eclipsing 8.56 minutes orbital period mass-transferring binary. The Astrophysical Journal. 1000(2), 237.","mla":"Chickles, Emma T., et al. “An Eclipsing 8.56 Minutes Orbital Period Mass-Transferring Binary.” <i>The Astrophysical Journal</i>, vol. 1000, no. 2, 237, IOP Publishing, 2026, doi:<a href=\"https://doi.org/10.3847/1538-4357/ae4871\">10.3847/1538-4357/ae4871</a>.","apa":"Chickles, E. T., Chakraborty, J., Burdge, K. B., Dhillon, V. S., Draghis, P., El-Badry, K., … Simcoe, R. (2026). An eclipsing 8.56 minutes orbital period mass-transferring binary. <i>The Astrophysical Journal</i>. IOP Publishing. <a href=\"https://doi.org/10.3847/1538-4357/ae4871\">https://doi.org/10.3847/1538-4357/ae4871</a>"},"oa":1,"publication":"The Astrophysical Journal"},{"article_type":"original","intvolume":"       547","file":[{"success":1,"file_id":"21834","date_updated":"2026-05-07T07:51:06Z","relation":"main_file","file_size":5955512,"checksum":"a64094199db4dedb12fc121b7c65fe97","creator":"dernst","date_created":"2026-05-07T07:51:06Z","file_name":"2026_MNRAS_Parsons.pdf","access_level":"open_access","content_type":"application/pdf"}],"volume":547,"oa_version":"Published Version","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","has_accepted_license":"1","author":[{"first_name":"S. G.","last_name":"Parsons","full_name":"Parsons, S. G."},{"full_name":"Brown, A. J.","last_name":"Brown","first_name":"A. J."},{"full_name":"Casewell, S. L.","last_name":"Casewell","first_name":"S. L."},{"full_name":"Littlefair, S. P.","last_name":"Littlefair","first_name":"S. P."},{"first_name":"Joannes C","last_name":"van Roestel","id":"4d122fc8-6083-11f0-87a5-97d68b860333","full_name":"van Roestel, Joannes C"},{"full_name":"Rebassa-Mansergas, A.","last_name":"Rebassa-Mansergas","first_name":"A."},{"full_name":"Murillo-Ojeda, R.","last_name":"Murillo-Ojeda","first_name":"R."},{"first_name":"M.","last_name":"Zorotovic","full_name":"Zorotovic, M."},{"full_name":"Schreiber, M. R.","last_name":"Schreiber","first_name":"M. R."},{"full_name":"Bagnulo, S.","last_name":"Bagnulo","first_name":"S."},{"last_name":"Stroet","first_name":"M. A.","full_name":"Stroet, M. A."},{"full_name":"Castro Segura, N.","last_name":"Castro Segura","first_name":"N."},{"first_name":"V. S.","last_name":"Dhillon","full_name":"Dhillon, V. S."},{"full_name":"Dyer, M. J.","last_name":"Dyer","first_name":"M. J."},{"full_name":"Garbutt, J. A.","last_name":"Garbutt","first_name":"J. A."},{"full_name":"Green, M. J.","last_name":"Green","first_name":"M. J."},{"full_name":"Jarvis, D.","last_name":"Jarvis","first_name":"D."},{"full_name":"Kennedy, M. R.","first_name":"M. R.","last_name":"Kennedy"},{"last_name":"Kerry","first_name":"P.","full_name":"Kerry, P."},{"full_name":"Mccormac, J.","last_name":"Mccormac","first_name":"J."},{"full_name":"Munday, J.","last_name":"Munday","first_name":"J."},{"last_name":"Pelisoli","first_name":"I.","full_name":"Pelisoli, I."},{"full_name":"Pike, E.","first_name":"E.","last_name":"Pike"},{"first_name":"D. I.","last_name":"Sahman","full_name":"Sahman, D. I."},{"last_name":"Yates","first_name":"A.","full_name":"Yates, A."}],"file_date_updated":"2026-05-07T07:51:06Z","publication_status":"published","department":[{"_id":"IlCa"}],"scopus_import":"1","quality_controlled":"1","OA_type":"gold","arxiv":1,"day":"01","_id":"21780","year":"2026","ddc":["520"],"publication":"Monthly Notices of the Royal Astronomical Society","date_updated":"2026-05-07T07:51:58Z","date_published":"2026-04-01T00:00:00Z","month":"04","article_number":"stag521","abstract":[{"lang":"eng","text":"It is predicted that half or more of all cataclysmic variables (CVs) should have evolved past the period minimum and now exist as so-called period bouncers where a white dwarf should be accreting from a Roche lobe filling substellar companion. However, this prediction stands in stark contrast to observations, where only a few per cent of CVs are found in this evolutionary phase. A potential solution to this discrepancy is that a magnetic field emerges from within the white dwarf after the system has reached the period minimum. The transfer of angular momentum from the spin of the white dwarf into the orbit then pushes the two stars apart, detaching them for potentially billions of years. Here we present the discovery of ZTF J021804.16+071152.93, a detached 0.69 +- 0.01 M⁠, 19 MG magnetic white dwarf plus 37 +- 5MJup brown dwarf binary with an orbital period of 1.7 h. The kinematics of the system indicate that it is a high probability member of the Galactic thick disc. However, this strongly disagrees with the much younger age of the system obtained from the white dwarf parameters, implying that the system may have been accreting in the past. This system is therefore consistent with having detached as a result of the emergence of the magnetic field of the white dwarf when the system was still mass transferring, and may represent the ultimate fate for many (perhaps even most) CVs."}],"citation":{"ista":"Parsons SG, Brown AJ, Casewell SL, Littlefair SP, van Roestel JC, Rebassa-Mansergas A, Murillo-Ojeda R, Zorotovic M, Schreiber MR, Bagnulo S, Stroet MA, Castro Segura N, Dhillon VS, Dyer MJ, Garbutt JA, Green MJ, Jarvis D, Kennedy MR, Kerry P, Mccormac J, Munday J, Pelisoli I, Pike E, Sahman DI, Yates A. 2026. ZTF J021804.16+071152.93: A dead cataclysmic variable and potential solution to the missing period bouncer cataclysmic variables. Monthly Notices of the Royal Astronomical Society. 547(4), stag521.","chicago":"Parsons, S. G., A. J. Brown, S. L. Casewell, S. P. Littlefair, Joannes C van Roestel, A. Rebassa-Mansergas, R. Murillo-Ojeda, et al. “ZTF J021804.16+071152.93: A Dead Cataclysmic Variable and Potential Solution to the Missing Period Bouncer Cataclysmic Variables.” <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford University Press, 2026. <a href=\"https://doi.org/10.1093/mnras/stag521\">https://doi.org/10.1093/mnras/stag521</a>.","short":"S.G. Parsons, A.J. Brown, S.L. Casewell, S.P. Littlefair, J.C. van Roestel, A. Rebassa-Mansergas, R. Murillo-Ojeda, M. Zorotovic, M.R. Schreiber, S. Bagnulo, M.A. Stroet, N. Castro Segura, V.S. Dhillon, M.J. Dyer, J.A. Garbutt, M.J. Green, D. Jarvis, M.R. Kennedy, P. Kerry, J. Mccormac, J. Munday, I. Pelisoli, E. Pike, D.I. Sahman, A. Yates, Monthly Notices of the Royal Astronomical Society 547 (2026).","ama":"Parsons SG, Brown AJ, Casewell SL, et al. ZTF J021804.16+071152.93: A dead cataclysmic variable and potential solution to the missing period bouncer cataclysmic variables. <i>Monthly Notices of the Royal Astronomical Society</i>. 2026;547(4). doi:<a href=\"https://doi.org/10.1093/mnras/stag521\">10.1093/mnras/stag521</a>","ieee":"S. G. Parsons <i>et al.</i>, “ZTF J021804.16+071152.93: A dead cataclysmic variable and potential solution to the missing period bouncer cataclysmic variables,” <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 547, no. 4. Oxford University Press, 2026.","apa":"Parsons, S. G., Brown, A. J., Casewell, S. L., Littlefair, S. P., van Roestel, J. C., Rebassa-Mansergas, A., … Yates, A. (2026). ZTF J021804.16+071152.93: A dead cataclysmic variable and potential solution to the missing period bouncer cataclysmic variables. <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford University Press. <a href=\"https://doi.org/10.1093/mnras/stag521\">https://doi.org/10.1093/mnras/stag521</a>","mla":"Parsons, S. G., et al. “ZTF J021804.16+071152.93: A Dead Cataclysmic Variable and Potential Solution to the Missing Period Bouncer Cataclysmic Variables.” <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 547, no. 4, stag521, Oxford University Press, 2026, doi:<a href=\"https://doi.org/10.1093/mnras/stag521\">10.1093/mnras/stag521</a>."},"oa":1,"acknowledgement":"The results presented in this paper are based on observations collected at the European Southern Observatory under programme IDs 113.D-0277 and 114.D-0066 and on observations made with the Gran Telescopio Canarias (programme ID GTC119-23B), installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, on the island of La Palma.\r\n\r\nSGP acknowledges support by the Science and Technology Facilities Council (grant ST/B001174/1). ARM acknowledges support from MINECO under the PID2023-148661NB-I00 grant and by the AGAUR/Generalitat de Catalunya grant SGR-386/2021. RMO was funded by INTA through grant PRE-OBSERVATORIO and acknowledges support from project PID2023-146210NB-I00 funded by MICIU/AEI/10.13039/501100011033 and by ERDF/EU. MZ acknowledges support from FONDECYT (grants 1250525 and 1221059). VSD and HiPERCAM were funded by the Science and Technology Facilities Council (grant ST/Z000033/1). MRS thanks for support from FONDECYT (grant No. 1221059). This project received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (Grant agreement numbers 101002408-MOS100PC).","language":[{"iso":"eng"}],"title":"ZTF J021804.16+071152.93: A dead cataclysmic variable and potential solution to the missing period bouncer cataclysmic variables","issue":"4","type":"journal_article","OA_place":"publisher","DOAJ_listed":"1","publisher":"Oxford University Press","publication_identifier":{"eissn":["1365-2966"],"issn":["0035-8711"]},"tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","short":"CC BY (4.0)"},"article_processing_charge":"Yes","doi":"10.1093/mnras/stag521","external_id":{"arxiv":["2603.12888"]},"date_created":"2026-05-03T22:01:37Z","status":"public"},{"publication_identifier":{"eissn":["1448-6083"],"issn":["1323-3580"]},"article_processing_charge":"Yes (in subscription journal)","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","short":"CC BY (4.0)"},"doi":"10.1017/pasa.2026.10184","status":"public","date_created":"2026-05-07T08:55:00Z","PlanS_conform":"1","article_number":"e052","month":"03","date_published":"2026-03-27T00:00:00Z","date_updated":"2026-05-12T06:57:40Z","citation":{"ama":"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>","short":"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).","ieee":"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.","ista":"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.","chicago":"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>.","mla":"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>.","apa":"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>"},"oa":1,"abstract":[{"text":"AM CVn stars are ultra-compact semi-detached binaries consisting of a white dwarf primary and a hydrogen-depleted secondary. In this\r\npaper, we present spectroscopic and photometric results of 15 transient sources pre-classified as AM CVn candidates. Our analysis confirms\r\n9 systems of the type AM CVn, 3 hydrogen-rich cataclysmic variables (accreting white dwarfs with near-main-sequence stars for donors),\r\nand 3 systems that could be evolved cataclysmic variables. Eight of the AM CVn stars are analysed spectroscopically for the first time,\r\nwhich increases the number of spectroscopically confirmed AM CVns by about 10%. TESS data revealed the orbital period of the AM CVn\r\nstar ASASSN-20pv to be Porb =27.282 min, which helps to constrain the possible values of its mass ratio. TESS also helped to determine\r\nthe superhump periods of one AM CVn star (ASASSN-19ct, Psh =30.94 min) and two cataclysmic variables we classify as WZ Sge stars\r\n(Psh =90.77 min for ZTF18aaaasnn and Psh =91.6min for ASASSN-15na).We identified very different abundances in the spectra of theAM\r\nCVns binaries ASASSN-15kf and ASASSN-20pv (both Porb ∼27.5min), suggesting different type of donors. Six of the studied AMCVns are\r\nX-ray sources, which helped to determine their mass accretion rates. Photometry shows that the duration of all the superoutbursts detected\r\nin the AM CVns is consistent with expectations from the disc instability model. Finally, we provide refined criteria for the identification of\r\nnew systems using all-sky surveys such as LSST.","lang":"eng"}],"publication":"Publications of the Astronomical Society of Australia","type":"journal_article","publisher":"Cambridge University Press","OA_place":"publisher","language":[{"iso":"eng"}],"acknowledgement":"We are grateful to the anonymous referee for providing\r\nus with useful comments and suggestions that improved our manuscript.\r\nJK and LRS acknowledge support from NASA grants NNH22ZDA001N-6152\r\nand 80NSSC24K0638. MPM is partially supported by the Swiss National\r\nScience Foundation IZSTZ0_216537 and by UNAM PAPIIT-IG101224. Based\r\non observations obtained at the international Gemini Observatory, a program\r\nof NSF NOIRLab, which is managed by the Association of Universities for\r\nResearch in Astronomy (AURA) under a cooperative agreement with the U.S.\r\nNational Science Foundation on behalf of the Gemini Observatory partnership:\r\nthe U.S. National Science Foundation (United States), National Research\r\nCouncil (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério\r\nda Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea\r\nAstronomy and Space Science Institute (Republic of Korea). The Gemini\r\ndata were obtained from programs GN-2023B-Q-310 and GS-2024A-Q-311\r\n(PI: Rivera Sandoval) and processed using DRAGONS (Data Reduction for\r\nAstronomy from Gemini Observatory North and South) The Digitized Sky\r\nSurveys were produced at the Space Telescope Science Institute under U.S.\r\nGovernment grant NAG W-2166. The images of these surveys are based on\r\nphotographic data obtained using the Oschin Schmidt Telescope on Palomar\r\nMountain and the UK Schmidt Telescope. The plates were processed into the\r\npresent compressed digital form with the permission of these institutions.\r\nThe National Geographic Society – Palomar Observatory Sky Atlas (POSS-I)\r\nwas made by the California Institute of Technology with grants from the\r\nNational Geographic Society. The Second Palomar Observatory Sky Survey\r\n(POSS-II) was made by the California Institute of Technology with funds\r\nfrom the National Science Foundation, the National Geographic Society, the\r\nSloan Foundation, the Samuel Oschin Foundation, and the Eastman Kodak\r\nCorporation. The Oschin Schmidt Telescope is operated by the California\r\nInstitute of Technology and Palomar Observatory. The UK Schmidt Telescope\r\nwas operated by the Royal Observatory Edinburgh, with funding from the\r\nUK Science and Engineering Research Council (later the UK Particle Physics\r\nand Astronomy Research Council), until 1988 June, and thereafter by the\r\nAnglo-Australian Observatory. The blue plates of the southern Sky Atlas\r\nand its Equatorial Extension (together known as the SERC-J), as well as the\r\nEquatorial Red (ER), and the Second Epoch [red] Survey (SES) were all taken\r\nwith the UK Schmidt. Supplemental funding for sky-survey work at the ST\r\nScI is provided by the European Southern Observatory. Based on observations\r\nobtained with the Samuel Oschin Telescope 48-inch and the 60-inch Telescope\r\nat the Palomar Observatory as part of the Zwicky Transient Facility project.\r\nZTF is supported by the National Science Foundation under Grants No. AST-\r\n1440341 and AST-2034437 and a collaboration including current partners\r\nCaltech, IPAC, the Oskar Klein Center at Stockholm University, the University\r\nof Maryland, University of California, Berkeley, the University of Wisconsin\r\nat Milwaukee, University of Warwick, Ruhr University, Cornell University,\r\nNorthwestern University, and Drexel University. Operations are conducted\r\nby COO, IPAC, and UW. This work has used data from the European\r\nSpace Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia),\r\nprocessed by the Gaia Data Processing and Analysis Consortium (DPAC,\r\nhttps://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the\r\nDPAC has been provided by national institutions, in particular, the institutions\r\nparticipating in the Gaia Multilateral Agreement. We acknowledge with\r\nthanks the variable star observations from the AAVSO International Database\r\ncontributed by observers worldwide and used in this research. This paper\r\nincludes data collected by the TESS mission. Funding for the TESS mission\r\nis provided by the NASA Science Mission Directorate. Some of the data\r\npresented in this paper were obtained from the B. Mikulski Archive for Space\r\nTelescopes (MAST). This research has made use of the SIMBAD database,\r\noperated at CDS, Strasbourg, France. This research has made use of ‘Aladin\r\nsky atlas’ developed at CDS, Strasbourg Observatory, France. This research\r\nhas made use of the VizieR catalogue access tool, CDS, Strasbourg, France.","title":"A study of transients from ground-based surveys reveals new ultra-compact accreting white dwarf binaries","quality_controlled":"1","OA_type":"hybrid","department":[{"_id":"IlCa"}],"scopus_import":"1","_id":"21842","year":"2026","ddc":["520"],"day":"27","file":[{"creator":"dernst","file_name":"2026_PublAstronomicalSocAustralia_Kara.pdf","date_created":"2026-05-12T06:54:10Z","access_level":"open_access","content_type":"application/pdf","success":1,"file_id":"21862","date_updated":"2026-05-12T06:54:10Z","relation":"main_file","checksum":"f8f3cd3765948e8b276176c71c9d4e02","file_size":3681016}],"author":[{"full_name":"Kára, Jan","last_name":"Kára","first_name":"Jan"},{"full_name":"Rivera Sandoval, Liliana","first_name":"Liliana","last_name":"Rivera Sandoval"},{"first_name":"Wendy","last_name":"Mendoza","full_name":"Mendoza, Wendy"},{"last_name":"Maccarone","first_name":"Thomas","full_name":"Maccarone, Thomas"},{"first_name":"Manuel","last_name":"Pichardo Marcano","full_name":"Pichardo Marcano, Manuel"},{"last_name":"Salazar Manzano","first_name":"Luis E.","full_name":"Salazar Manzano, Luis E."},{"full_name":"Oelkers, Ryan J.","last_name":"Oelkers","first_name":"Ryan J."},{"id":"4d122fc8-6083-11f0-87a5-97d68b860333","full_name":"van Roestel, Joannes C","first_name":"Joannes C","last_name":"van Roestel"}],"oa_version":"Published Version","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","has_accepted_license":"1","volume":43,"intvolume":"        43","article_type":"original","publication_status":"published","file_date_updated":"2026-05-12T06:54:10Z"},{"intvolume":"       548","article_type":"original","oa_version":"Published Version","has_accepted_license":"1","user_id":"2DF688A6-F248-11E8-B48F-1D18A9856A87","author":[{"full_name":"Green, Matthew J","first_name":"Matthew J","last_name":"Green"},{"first_name":"Thomas R","last_name":"Marsh","full_name":"Marsh, Thomas R"},{"first_name":"Joannes C","last_name":"van Roestel","id":"4d122fc8-6083-11f0-87a5-97d68b860333","full_name":"van Roestel, Joannes C"},{"full_name":"Wong, Tin Long Sunny","first_name":"Tin Long Sunny","last_name":"Wong"},{"first_name":"Diogo","last_name":"Belloni","full_name":"Belloni, Diogo"},{"full_name":"Kilic, Mukremin","first_name":"Mukremin","last_name":"Kilic"},{"full_name":"Breedt, Elmé","first_name":"Elmé","last_name":"Breedt"},{"full_name":"Brown, Alex","first_name":"Alex","last_name":"Brown"},{"last_name":"Copperwheat","first_name":"Chris M","full_name":"Copperwheat, Chris M"},{"last_name":"Chakpor","first_name":"Anurak","full_name":"Chakpor, Anurak"},{"last_name":"Dhillon","first_name":"V S","full_name":"Dhillon, V S"},{"full_name":"Segura, Noel Castro","last_name":"Segura","first_name":"Noel Castro"},{"full_name":"Dyer, Martin J","last_name":"Dyer","first_name":"Martin J"},{"full_name":"Garbutt, James","last_name":"Garbutt","first_name":"James"},{"last_name":"Jarvis","first_name":"Dan","full_name":"Jarvis, Dan"},{"first_name":"Vasu","last_name":"Kengkriangkrai","full_name":"Kengkriangkrai, Vasu"},{"last_name":"Kennedy","first_name":"Mark R","full_name":"Kennedy, Mark R"},{"first_name":"Paul","last_name":"Kerry","full_name":"Kerry, Paul"},{"last_name":"Kupfer","first_name":"Thomas","full_name":"Kupfer, Thomas"},{"full_name":"Littlefair, S P","first_name":"S P","last_name":"Littlefair"},{"first_name":"James","last_name":"McCormac","full_name":"McCormac, James"},{"full_name":"Munday, James","first_name":"James","last_name":"Munday"},{"first_name":"Steven G","last_name":"Parsons","full_name":"Parsons, Steven G"},{"full_name":"Pike, Eleanor","last_name":"Pike","first_name":"Eleanor"},{"full_name":"Pelisoli, Ingrid","last_name":"Pelisoli","first_name":"Ingrid"},{"first_name":"Pablo","last_name":"Rodríguez-Gil","full_name":"Rodríguez-Gil, Pablo"},{"full_name":"Sahman, David I","first_name":"David I","last_name":"Sahman"},{"first_name":"Amalie","last_name":"Yates","full_name":"Yates, Amalie"}],"volume":548,"file":[{"relation":"main_file","checksum":"2c4463926c5cb84ce555ef2005b52ddd","file_size":3960296,"success":1,"file_id":"21903","date_updated":"2026-05-21T06:37:42Z","access_level":"open_access","content_type":"application/pdf","creator":"dernst","file_name":"2026_MNRAS_Green.pdf","date_created":"2026-05-21T06:37:42Z"}],"file_date_updated":"2026-05-21T06:37:42Z","publication_status":"published","scopus_import":"1","department":[{"_id":"IlCa"}],"OA_type":"gold","quality_controlled":"1","day":"09","arxiv":1,"year":"2026","ddc":["520"],"_id":"21897","publication":"Monthly Notices of the Royal Astronomical Society","citation":{"apa":"Green, M. J., Marsh, T. R., van Roestel, J. C., Wong, T. L. S., Belloni, D., Kilic, M., … Yates, A. (2026). No period change in two long-period AM CVn binaries. <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford University Press. <a href=\"https://doi.org/10.1093/mnras/stag673\">https://doi.org/10.1093/mnras/stag673</a>","mla":"Green, Matthew J., et al. “No Period Change in Two Long-Period AM CVn Binaries.” <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 548, no. 3, stag673, Oxford University Press, 2026, doi:<a href=\"https://doi.org/10.1093/mnras/stag673\">10.1093/mnras/stag673</a>.","ista":"Green MJ, Marsh TR, van Roestel JC, Wong TLS, Belloni D, Kilic M, Breedt E, Brown A, Copperwheat CM, Chakpor A, Dhillon VS, Segura NC, Dyer MJ, Garbutt J, Jarvis D, Kengkriangkrai V, Kennedy MR, Kerry P, Kupfer T, Littlefair SP, McCormac J, Munday J, Parsons SG, Pike E, Pelisoli I, Rodríguez-Gil P, Sahman DI, Yates A. 2026. No period change in two long-period AM CVn binaries. Monthly Notices of the Royal Astronomical Society. 548(3), stag673.","chicago":"Green, Matthew J, Thomas R Marsh, Joannes C van Roestel, Tin Long Sunny Wong, Diogo Belloni, Mukremin Kilic, Elmé Breedt, et al. “No Period Change in Two Long-Period AM CVn Binaries.” <i>Monthly Notices of the Royal Astronomical Society</i>. Oxford University Press, 2026. <a href=\"https://doi.org/10.1093/mnras/stag673\">https://doi.org/10.1093/mnras/stag673</a>.","short":"M.J. Green, T.R. Marsh, J.C. van Roestel, T.L.S. Wong, D. Belloni, M. Kilic, E. Breedt, A. Brown, C.M. Copperwheat, A. Chakpor, V.S. Dhillon, N.C. Segura, M.J. Dyer, J. Garbutt, D. Jarvis, V. Kengkriangkrai, M.R. Kennedy, P. Kerry, T. Kupfer, S.P. Littlefair, J. McCormac, J. Munday, S.G. Parsons, E. Pike, I. Pelisoli, P. Rodríguez-Gil, D.I. Sahman, A. Yates, Monthly Notices of the Royal Astronomical Society 548 (2026).","ama":"Green MJ, Marsh TR, van Roestel JC, et al. No period change in two long-period AM CVn binaries. <i>Monthly Notices of the Royal Astronomical Society</i>. 2026;548(3). doi:<a href=\"https://doi.org/10.1093/mnras/stag673\">10.1093/mnras/stag673</a>","ieee":"M. J. Green <i>et al.</i>, “No period change in two long-period AM CVn binaries,” <i>Monthly Notices of the Royal Astronomical Society</i>, vol. 548, no. 3. Oxford University Press, 2026."},"oa":1,"abstract":[{"lang":"eng","text":"Ultracompact binary systems, consisting of two compact objects in an orbit $\\lesssim 0.5 {\\rm R}_\\odot$, should exhibit measurable rates of orbital period change ($\\dot{P} \\ne 0$) due to the emission of gravitational waves (GWs). Measurements of $\\dot{P}$ have so far been limited to the shortest-period ultracompact binaries ($\\lesssim 20$  min). Among the AM CVn-type subclass, several works have proposed the presence of extra angular momentum loss beyond GW emission, with magnetic braking being a widely discussed mechanism. If present, this magnetic braking would dominate the angular momentum loss of AM CVn-type binaries with orbital periods $\\gtrsim 30$ min. In this work, we present a long-term eclipse timing study of two AM CVn-type binaries, YZ LMi and Gaia14aae, with respective orbital periods of 28.3 min and 49.7 min and continuous observations since 2006 and 2015. Both systems show $\\dot{P}$ consistent with zero within $2\\sigma$. Their $3\\sigma$ upper limits are $1.1 \\times 10^{-13}\\, {\\rm s \\, s}^{-1}$ and $9.7 \\times 10^{-14}\\, {\\rm s \\, s}^{-1}$, respectively. These non-detections are most simply explained by a scenario in which secular angular momentum loss is not substantially stronger than GW emission at all orbital periods, but is combined with deviations from the secular $\\dot{P}$ whose time-scales span decades but whose amplitude is $\\lesssim 10^{-13}\\, {\\rm s \\, s}^{-1}$. Our non-detections of $\\dot{P}$ represent a limit on the strength of any enhanced angular momentum loss beyond pure GW emission."}],"article_number":"stag673","date_published":"2026-04-09T00:00:00Z","month":"04","date_updated":"2026-05-21T06:41:41Z","issue":"3","title":"No period change in two long-period AM CVn binaries","language":[{"iso":"eng"}],"acknowledgement":"We are grateful to the anonymousreferee fortheirinsightful comments. MJG thanks Mitch Begelman and the JILA department at the University of Colorado, Boulder, for providing office space at which much of this paper was written. This work is supported in part by the United States National Aeronautics and Space Administration (NASA) under grants\r\n80NSSC24K0436, 80NSSC22K0479, and 80NSSC24K0380, and the United States National Science Foundation (NSF) under grant AST-2508429. VSD and HiPERCAM are funded by the Science and Technology Facilities Council (grant ST/Z000033/1). IP acknowledges support from the Royal Society through a University Research Fellowship (URF\\R1\\231496). This project has received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (grant agreement numbers 101002408 – MOS100PC). CMC receives funding from United Kingdom Research and Innovation grant numbers ST/X005933/1 and ST/W001934/1. This article is based in part on observations made in the Observatorios de Canarias del Instituto de Astrofísica de Canarias (IAC) with the the William Herschel Telescope (WHT) operated on the island of La Palma by the Isaac Newton Group (ING) in the Observatorio del Roque de los Muchachos. It is also based in part on observations made with the Gran Telescopio Canarias (GTC) under proposal ID GTC18-24A, installed at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, in the island of La Palma. Further data were obtained using the 2.4 m Thai National Telescope (TNT) operated by the National Astronomy Research Institute of Thailand\r\n(NARIT), and the 200-inch Hale Telescope at Palomar Observatory operated by the California Institute of Technology. Software packages used in this work include the ultracam and hipercam reduction pipelines, lcurve (C. M. Copperwheat et al. 2010), numpy, astropy, matplotlib, and emcee (D. Foreman-Mackey et al. 2013).","publisher":"Oxford University Press","DOAJ_listed":"1","OA_place":"publisher","type":"journal_article","doi":"10.1093/mnras/stag673","tmp":{"legal_code_url":"https://creativecommons.org/licenses/by/4.0/legalcode","name":"Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)","image":"/images/cc_by.png","short":"CC BY (4.0)"},"article_processing_charge":"Yes","publication_identifier":{"issn":["0035-8711"],"eissn":["1365-2966"]},"PlanS_conform":"1","status":"public","keyword":["binaries: close – stars","dwarf novae – novae","cataclysmic variables – white dwarfs"],"external_id":{"arxiv":["2604.06460"]},"date_created":"2026-05-20T14:34:03Z"}]