6533b7cefe1ef96bd12572c2
RESEARCH PRODUCT
On the maximum efficiency of the propeller mass-ejection mechanism
Maurizio FalangaE. BozzoE. BozzoT. Di SalvoRosalba PernaLuigi StellaLuciano Burderisubject
PhysicsAstrophysics::High Energy Astrophysical PhenomenaAstrophysics (astro-ph)PropellerFOS: Physical sciencesOrder (ring theory)Astronomy and AstrophysicsAstrophysics::Cosmology and Extragalactic AstrophysicsAstrophysicsStar (graph theory)AstrophysicsMagnetic fieldRotational energyNeutron starSpace and Planetary ScienceAstrophysics::Solar and Stellar AstrophysicsAstrophysics::Earth and Planetary AstrophysicsLow MassAstrophysics::Galaxy AstrophysicsSpin-½description
Aims. We derive simple estimates of the maximum efficiency with which matter can be ejected by the propeller mechanism in disk-fed, rotating magnetic neutron stars. Some binary evolution scenarios envisage that this mechanism is responsible for expelling to infinity the mass inflowing at a low rate from the companion star, therefore limiting the total amount of mass that can be accreted by the neutron star. Methods. We demonstrate that, for typical neutron star parameters, a maximum of ��_{pro} < 5.7 (P_{-3})^{1/3} times more matter than accreted can be expelled through the propeller mechanism at the expenses of the neutron star rotational energy (P_{-3} is the NS spin period in unit of 10E-3 s). Approaching this value, however, would require a great deal of fine tuning in the system parameters and the properties of the interaction of matter and magnetic field at the magnetospheric boundary. Results. We conclude that some other mechanism must be invoked in order to prevent that too much mass accretes onto the neutron stars of some low mass X-ray binaries.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2007-01-13 |