Evolutionary Period Changes for 25 X-Ray Binaries and the Measurement of an Empirical Universal Law for Angular Momentum Loss in Accreting Binaries
I measure and collect timings of phase markers (like eclipse times) for the orbits of 25 X-ray binaries (XRBs) so as to calculate the steady evolutionary period change ( $\dot{P}$ ). I combine these with my observed $\dot{P}$ measures from 52 cataclysmic variables (CVs). Further, I subtract out the...
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2025-01-01
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| author | Bradley E. Schaefer |
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| description | I measure and collect timings of phase markers (like eclipse times) for the orbits of 25 X-ray binaries (XRBs) so as to calculate the steady evolutionary period change ( $\dot{P}$ ). I combine these with my observed $\dot{P}$ measures from 52 cataclysmic variables (CVs). Further, I subtract out the contributions from gravitational radiation ( ${\dot{P}}_{{\rm{GR}}}$ ) and mass transfer ( ${\dot{P}}_{{\rm{mt}}}$ ), deriving the period change from the residual unknown angular momentum loss ( ${\dot{P}}_{{\rm{AML}}}$ = $\dot{P}$ – ${\dot{P}}_{{\rm{GR}}}$ – ${\dot{P}}_{{\rm{mt}}}$ ). I have ${\dot{P}}_{{\rm{AML}}}$ measures for 77 XRBs and CVs, with these being direct measures of the driver of binary evolution. The venerable magnetic braking model of binary evolution has its most fundamental predictions tested, with most systems having predictions wrong by over 1 order of magnitude. Other proposed mechanisms to explain the angular momentum loss (AML) also fail, so we are left with no known mechanism that dominates the AML. An alternative path to the AML law is empirical, where my ${\dot{P}}_{{\rm{AML}}}$ measures are fitted to a power law involving the fundamental binary properties. With this, the dominant AML law for systems with orbital periods ( P ) from 0.13–1.0 day is ${\dot{P}}_{{\rm{AML}}}=-1500\times 1{0}^{-12}{P}^{1.29}{M}_{{\rm{prim}}}^{2.75}{M}_{{\rm{comp}}}^{-1.00}{\dot{M}}_{-8}^{0.43}$ , in appropriate units. Similar AML laws for binaries below the period gap and for binaries with P > 1.0 day are derived. These three AML laws are of good accuracy and are the best representations of the actual evolution for all 77 XRBs and CVs of all classes, so the three taken together can be called “universal.” |
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| series | The Astrophysical Journal |
| spelling | doaj-art-06ed3088da704f7d8fe90f34ffa900012025-08-20T03:16:56ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198813510.3847/1538-4357/add925Evolutionary Period Changes for 25 X-Ray Binaries and the Measurement of an Empirical Universal Law for Angular Momentum Loss in Accreting BinariesBradley E. Schaefer0https://orcid.org/0000-0002-2659-8763Department of Physics and Astronomy, Louisiana State University , Baton Rouge, LA 70803, USAI measure and collect timings of phase markers (like eclipse times) for the orbits of 25 X-ray binaries (XRBs) so as to calculate the steady evolutionary period change ( $\dot{P}$ ). I combine these with my observed $\dot{P}$ measures from 52 cataclysmic variables (CVs). Further, I subtract out the contributions from gravitational radiation ( ${\dot{P}}_{{\rm{GR}}}$ ) and mass transfer ( ${\dot{P}}_{{\rm{mt}}}$ ), deriving the period change from the residual unknown angular momentum loss ( ${\dot{P}}_{{\rm{AML}}}$ = $\dot{P}$ – ${\dot{P}}_{{\rm{GR}}}$ – ${\dot{P}}_{{\rm{mt}}}$ ). I have ${\dot{P}}_{{\rm{AML}}}$ measures for 77 XRBs and CVs, with these being direct measures of the driver of binary evolution. The venerable magnetic braking model of binary evolution has its most fundamental predictions tested, with most systems having predictions wrong by over 1 order of magnitude. Other proposed mechanisms to explain the angular momentum loss (AML) also fail, so we are left with no known mechanism that dominates the AML. An alternative path to the AML law is empirical, where my ${\dot{P}}_{{\rm{AML}}}$ measures are fitted to a power law involving the fundamental binary properties. With this, the dominant AML law for systems with orbital periods ( P ) from 0.13–1.0 day is ${\dot{P}}_{{\rm{AML}}}=-1500\times 1{0}^{-12}{P}^{1.29}{M}_{{\rm{prim}}}^{2.75}{M}_{{\rm{comp}}}^{-1.00}{\dot{M}}_{-8}^{0.43}$ , in appropriate units. Similar AML laws for binaries below the period gap and for binaries with P > 1.0 day are derived. These three AML laws are of good accuracy and are the best representations of the actual evolution for all 77 XRBs and CVs of all classes, so the three taken together can be called “universal.”https://doi.org/10.3847/1538-4357/add925Cataclysmic variable starsClassical novaeX-ray novaeX-ray binary starsStellar evolutionLow-mass x-ray binary stars |
| spellingShingle | Bradley E. Schaefer Evolutionary Period Changes for 25 X-Ray Binaries and the Measurement of an Empirical Universal Law for Angular Momentum Loss in Accreting Binaries The Astrophysical Journal Cataclysmic variable stars Classical novae X-ray novae X-ray binary stars Stellar evolution Low-mass x-ray binary stars |
| title | Evolutionary Period Changes for 25 X-Ray Binaries and the Measurement of an Empirical Universal Law for Angular Momentum Loss in Accreting Binaries |
| title_full | Evolutionary Period Changes for 25 X-Ray Binaries and the Measurement of an Empirical Universal Law for Angular Momentum Loss in Accreting Binaries |
| title_fullStr | Evolutionary Period Changes for 25 X-Ray Binaries and the Measurement of an Empirical Universal Law for Angular Momentum Loss in Accreting Binaries |
| title_full_unstemmed | Evolutionary Period Changes for 25 X-Ray Binaries and the Measurement of an Empirical Universal Law for Angular Momentum Loss in Accreting Binaries |
| title_short | Evolutionary Period Changes for 25 X-Ray Binaries and the Measurement of an Empirical Universal Law for Angular Momentum Loss in Accreting Binaries |
| title_sort | evolutionary period changes for 25 x ray binaries and the measurement of an empirical universal law for angular momentum loss in accreting binaries |
| topic | Cataclysmic variable stars Classical novae X-ray novae X-ray binary stars Stellar evolution Low-mass x-ray binary stars |
| url | https://doi.org/10.3847/1538-4357/add925 |
| work_keys_str_mv | AT bradleyeschaefer evolutionaryperiodchangesfor25xraybinariesandthemeasurementofanempiricaluniversallawforangularmomentumlossinaccretingbinaries |