Constraining the evolution of cataclysmic variables via the masses and accretion rates of their underlying white dwarfs
Year: 2021
Type: article
Abstract: ABSTRACT We report on the masses (MWD), effective temperatures ($\rm{T_\mathrm{eff}}$), and secular mean accretion rates ($\langle \dot{M} \rangle$) of 43 cataclysmic variable (CV) white dwarfs, 42 of which were obtained from the combined analysis of their Hubble Space Telescope ultraviolet data with the parallaxes provided by the Early Third Data Release of the Gaia space mission, and one from the white dwarf gravitational redshift. Our results double the number of CV white dwarfs with an accurate mass measurement, bringing the total census to 89 systems. From the study of the mass distribution, we derive $\langle M_\mathrm{WD} \rangle = 0.81^{+0.16}_{-0.20}\, \mathrm{M_\odot }$, in perfect agreement with previous results, and find no evidence of any evolution of the mass with orbital period. Moreover, we identify five systems with MWD < 0.5 M⊙, which are most likely representative of helium-core white dwarfs, showing that these CVs are present in the overall population. We reveal the presence of an anticorrelation between the average accretion rates and the white dwarf masses for the systems below the $2\!-\!3\,$ h period gap. Since $\langle \dot{M} \rangle$ reflects the rate of system angular momentum loss, this correlation suggests the presence of an additional mechanism of angular momentum loss that is more efficient at low white dwarf masses. This is the fundamental concept of the recently proposed empirical prescription of consequential angular momentum loss (eCAML) and our results provide observational support for it, although we also highlight how its current recipe needs to be refined to better reproduce the observed scatter in $\rm{T_\mathrm{eff}}$ and $\langle \dot{M} \rangle$, and the presence of helium-core white dwarfs.
Authors: A F Pala, B T Gänsicke, D Belloni, S G Parsons, T R Marsh, M R Schreiber, E Breedt, C Knigge, E M Sion, P Szkody, D Townsley, L Bildsten, D Boyd, M J Cook, D De Martino, P Godon, S Kafka, V Kouprianov, K S Long, B Monard, G Myers, P Nelson, D Nogami, A Oksanen, R Pickard, G Poyner, D E Reichart, D Rodriguez Perez, J Shears, R Stubbings, O Toloza
Institutions: European Southern Observatory, European Space Agency, European Space Astronomy Centre, University of Warwick, Instituto Nacional de Pesquisas Espaciais, University of Sheffield, Millenium Nucleus for Planet Formation, Universidad Técnica Federico Santa María, University of Valparaíso, University of Cambridge, University of Southampton, Villanova University, University of Washington, University of Alabama, University of California, Santa Barbara, Kavli Institute for Theoretical Physics, British Astronomical Association, American Association of Variable Star Observers, Astronomical Observatory of Capodimonte, National Institute for Astrophysics, University of North Carolina at Chapel Hill, Space Telescope Science Institute, Eureka Scientific, Kyoto University, Hankasalmi Observatory
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, National Aeronautics and Space Administration, Diabetes Patient Advocacy Coalition, European Space Agency, Leverhulme Trust, European Commission, Fundação de Amparo à Pesquisa do Estado de São Paulo, Istituto Nazionale di Astrofisica, Agencia Nacional de Investigación y Desarrollo, Science and Technology Facilities Council
Awards: Warwick Astronomy and Astrophysics Consolidated Grant 2020-2023, G1869730875, G2035638860, G2180937516, G2679744610, G2981143, G300722360, G3207356259, Understanding Interacting Binary Stars Identified in Astronomical Surveys, G3853763931, G4573723818, G5484974171, G600531842, G6076980350, G7810866252, G8132079559, THE WHITE DWARF BINARY STAR PATHWAY PROJECT, G878044590, G896728979
OpenAlex ID: W3215406356