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Mass Loss and Evolution of Low-Mass X-ray Binaries

Mass Loss and Evolution of Low-Mass X-ray Binaries. Xiang-Dong Li Department of Astronomy Nanjing University 2009-5-20. Low-Mass X-ray Binaries (LMXBs). LMXBs and BMSPs. Magnetic fields. Radio PSRs. Spin-up line. MS PSRs. LMXBs. Spin Periods. From Deloye (2008).

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Mass Loss and Evolution of Low-Mass X-ray Binaries

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  1. Mass Loss and Evolution of Low-Mass X-ray Binaries Xiang-Dong Li Department of Astronomy Nanjing University 2009-5-20

  2. Low-Mass X-ray Binaries (LMXBs)

  3. LMXBs and BMSPs Magnetic fields Radio PSRs Spin-up line MS PSRs LMXBs Spin Periods

  4. From Deloye (2008)

  5. Stability of Mass Transfer • Two mass-radius exponents • Stability requires that after mass loss the star is still contained by its Roche lobe. From Soberman et al. (1997)

  6. Stable Mass Transfer • Driving mechanisms • Loss of orbital angular momentum • Gravitational radiation • Magnetic braking • Nuclear evolution of the companion star From Deloye (2008)

  7. Bifurcation Period in L/IMXB Evolution 1.5 M⊙ + 1.0 M⊙ From Pylyser & Savonije (1988)

  8. Porb-Mwd Relation in Wide Binary Pulsars From Rappaport et al. (1995)

  9. Thermal Timescale Mass Transfer • Mass transfer is dynamically stable but occurs on a thermal timescale if • This requires that the donor star has a radiative envelope, or the convective envelope is not too deep. From Deloye (2008)

  10. Evolution of IMXBs From Podsiadlowski et al. (2001) From Li (2002)

  11. Dynamically Unstable Mass Transfer • Massive donors with a convective envelope Common envelope evolution Ultracompact LMXBs From Deloye (2008)

  12. RGB/AGB TTMT CV-like UC-LMXBs

  13. Angular Momentum Loss by Magnetic Braking From Andronov et al. (2001) Standard MB Saturated MB

  14. Radio Pulsar Mass Measurements PSR J1911-5958: 1.4 (+0.16,-0.10) 2S0921-630: 1.44 (±0.10) PSR J1909-3744: 1.438 (±0.024) PSR J0437-4715: 1.58 (±0.18) PSR J1012+5307: 1.6 (±0.20) Mass transfer is highly non-conservative during I/LMXB evolution M = 1.35±0.04 M⊙ Thorsett & Chakrabarty 1999

  15. Mass and Angular Momentum Loss Outflow Wind Circumbinary disk

  16. Bifurcation Periods • Model 1: conservative mass transfer + traditional MB law • Model 2: conservative mass transfer + saturated MB law • Model 3: non-conservative mass transfer + mass loss from L1 point + saturated MB law • Model 4: non-conservative mass transfer + mass loss from the NS + saturated MB law

  17. From Ma & Li (2009a)

  18. From Ma & Li (2009a)

  19. Magnetic Capture Model for the Formation of UCXBs From van der Sluys et al. (2005)

  20. A CB Disk in Work From Ma & Li (2009b)

  21. From Ma & Li (2009b)

  22. Conclusions • The standard model for L/IMXBs still fails to reproduce some of the main features of the observed LMXBs and MS PSRs. • An unknown mechanism that mimics the features of a CB disk may be an important ingredient for understanding the overall evolution of I/LMXBs and CVs.

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