Formation of millisecond pulsars with CO white dwarf companions – II. Accretion, spin-up, true ages and comparison to MSPs with He white dwarf companions
By T. Tauris, N. Langer, Michael Kramer. 2012
162 citations recorded by the source corpus.
Millisecond pulsars are mainly characterized by their spin periods, B-fields and masses – quantities that are largely affected by previous interactions with a companion star in a binary system. In this paper, we investigate the formation mechanism of millisecond pulsars by considering the pulsar recycling process in both intermediate-mass X-ray binaries (IMXBs) and low-mass X-ray binaries (LMXBs). The IMXBs mainly lead to the formation of binary millisecond pulsars with a massive carbon–oxygen (CO) or an oxygen–neon–magnesium white dwarf (ONeMg WD) companion, whereas the LMXBs form recycled pulsars with a helium white dwarf (He WD) companion. We discuss the accretion physics leading to the spin-up line in the -diagram and demonstrate that such a line cannot be uniquely defined. We derive a simple expression for the amount of accreted mass needed for any given pulsar to achieve its equilibrium spin and apply this to explain the observed differences of the spin distributions of recycled pulsars with different types of companions. From numerical calculations we present further evidence for significant loss of rotational energy in accreting X-ray millisecond pulsars in LMXBs during the Roche-lobe decoupling phase (Tauris 2012) and demonstrate that the same effect is negligible in IMXBs. We examine the recycling of pulsars with CO WD companions via Case BB Roche-lobe overflow (RLO) of naked helium stars in post-common envelope binaries. We find that such pulsars typically accrete of the order of 0.002–0.007 M⊙ which is just about sufficient to explain their observed spin periods. We introduce isochrones of radio millisecond pulsars in the -diagram to follow their spin evolution and discuss their true ages from comparison with observations. Finally, we apply our results of the spin-up process to complement our investigation of the massive pulsar PSR J1614−2230 from Paper I, confirming that this system formed via stable Case A RLO in an IMXB and enabling us to put new constraints on the birth masses of a number of recycled pulsars.
Subfields: Astronomy and Astrophysics
View Paper: https://www.semanticscholar.org/paper/4ddd3e0c137e8beb06a9e3fb6729f1e32b951657
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In Astronomy and Astrophysics
Citations in the corpus
- Progenitors of gravitational wave mergers: binary evolution with the stellar grid-based code ComBinE (2018, background): “This formation channel, however, only works for the evolution of two stars with a mass ratio close to 1 and is thus not suited to explain the observations of tight binaries with, for example, a NS orbited by a WD companion (Tauris et al. 2012).”
- Modeling Dense Star Clusters in the Milky Way and Beyond with the CMC Cluster Catalog (2019, background): “MSPs are generally thought to form when an old, slowly spinning NS is spun up through mass transfer from a Roche-lobe-filling binary companion (e.g., Rappaport et al. 1995; Tauris et al. 2012).”
- Ultra-stripped supernovae: progenitors and fate (2015, methodology): “Forrecent applications of BEC to X-ray binaries and further description of Case BB RLO, see e.g. Tauris et al. (2011, 2012, 2013); Lazarus et al. (2014); Istrate et al. (2014).”
- Formation of Double Neutron Star Systems (2017, methodology): “Such systems show clear evidence of having evolved through a stage with a NS embedded in a CE (van den Heuvel & Taam 1984; Tauris et al. 2012).”
- PULSAR J0453+1559: A DOUBLE NEUTRON STAR SYSTEM WITH A LARGE MASS ASYMMETRY (2015, result): “These numbers are similar to what we observe for other recycled pulsars with massive companions, and they indicate that this pulsar was mildly recycled by the accretion of matter from the progenitor of the current companion star (Tauris et al. 2012).”
- Models of low-mass helium white dwarfs including gravitational settling, thermal and chemical diffusion, and rotational mixing (2016, methodology): “Unfortunately, the true age of a recycled pulsar cannot be determined from its characteristic spin-down age as this method has proved unreliable by a factor of 10 or more (Camilo et al. 1994; Lorimer et al. 1995; Tauris 2012; Tauris et al. 2012).”
- COSMIC Variance in Binary Population Synthesis (2019, background): “We assume “magnetic field burying” (e.g., Bhattacharya & van den Heuvel 1991; Rappaport et al. 1995; Kiel et al. 2008; Tauris et al. 2012) for the magnetic field decay during mass accretion B = B0 1 + (∆M/10−6M ) exp ( − T − tacc τ ) .”