Formation of redbacks via accretion induced collapse

Abstract

We examine the growing class of binary millisecond pulsars known as redbacks. In these systems the pulsar's companion has a mass between 0.1 and about 0.5 solar masses in an orbital period of less than 1.5 days. All show extended radio eclipses associated with circumbinary material. They do not lie on the period-companion mass relation expected from the canonical intermediate-mass X-ray binary evolution in which the companion filled its Roche lobe as a red giant and has now lost its envelope and cooled as a white dwarf. The redbacks lie closer to, but usually at higher period than, the period-companion mass relation followed by cataclysmic variables and low-mass X-ray binaries. In order to turn on as a pulsar mass accretion on to a neutron star must be sufficiently weak, considerably weaker than expected in systems with low-mass main-sequence companions driven together by magnetic braking or gravitational radiation. If a neutron star is formed by accretion induced collapse of a white dwarf as it approaches the Chandrasekhar limit some baryonic mass is abruptly lost to its binding energy so that its effective gravitational mass falls. We propose that redbacks form when accretion induced collapse of a white dwarf takes place during cataclysmic variable binary evolution because the loss of gravitational mass makes the orbit expand suddenly so that the companion no longer fills its Roche lobe. Once activated, the pulsar can ablate its companion and so further expand the orbit and also account for the extended eclipses in the radio emission of the pulsar that are characteristic of these systems. The whole period-companion mass space occupied by the redbacks can be populated in this way.

12 pages, 7 figures

References in corpus (11)

• Modules for Experiments in Stellar Astrophysics (MESA)
• The ATNF Pulsar Catalogue
• A Radio Pulsar/X-ray Binary Link
• The type Ia supernova SNLS-03D3bb from a super-Chandrasekhar-mass white dwarf star
• Eight New Millisecond Pulsars in NGC 6440 and NGC 6441
• The Internal Shear of Type Ia Supernova Progenitors During Accretion and Simmering
• The birth properties of Galactic millisecond radio pulsars
• GBT Discovery of Two Binary Millisecond Pulsars in the Globular Cluster M30
• A puzzling millisecond pulsar companion in NGC 6266
• The puzzling properties of the Helium White Dwarf orbiting the millisecond pulsar PSR J1911-5958A in NGC 6752
• The role of binding energies of neutron stars on the accretion driven evolution

Cited by in corpus (8)

• Gamma-ray Timing of Redback PSR J2339-0533: Hints for Gravitational Quadrupole Moment Changes
• Formation of Binary Millisecond Pulsars by Accretion-Induced Collapse of White Dwarfs under Wind-Driven Evolution
• Evolution of Low-Mass X-ray Binaries: the Effect of Donor Evaporation
• Evolution of post-Accretion Induced Collapse Binaries: the Effect of Evaporation
• Identifying the formation mechanism of redback pulsars
• The peculiar chemical abundance of the transitional millisecond pulsar PSR J1023+0038 -- Li enhancement
• Evolution of redback radio pulsars in globular clusters
• Does PSR J1417-4402 system behave as a "Redback"?