Context. Recently the discovery of
Aims: We want to understand the evolutionary history of PSR J1719-1438, and determine under which circumstances it could have evolved from an UCXB.
Methods: We model UCXB evolution varying the donor size and investigate the effect of a wind mass loss from the donor, and compare the results with the observed characteristics of PSR J1719-1438.
Results: An UCXB can reach a 2.2 h orbit within the age of the Universe, provided that 1) the millisecond pulsar can significantly heat and expand the donor by pulsar irradiation, or 2) the system loses extra orbital angular momentum, e.g. via a fast wind from the donor.
Conclusions: The most likely scenario for the formation of PSR J1719-1438 is UCXB evolution driven by angular momentum loss via the usual gravitational wave emission, which is enhanced by angular momentum loss via a donor wind of ≳3 × 10-13 M☉ yr-1. Depending on the size of the donor during the evolution, the companion presently probably has a mass of ~1-3 Jupiter masses, making it a very low mass white dwarf as proposed by Bailes et al. Its composition can be either helium or carbon-oxygen. A helium white dwarf companion makes the long (for an UCXB) orbital period easier to explain, but the required inclination makes it a priori less likely than a carbon-oxygen white dwarf.
Astronomy and Astrophysics
- Pub Date:
- May 2012
- pulsars: individual: J1719-1438;
- binaries: close;
- planets and satellites: formation;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Earth and Planetary Astrophysics
- 5 pages, 4 figures. Accepted for publication in Astronomy and Astrophysics. v2: Updated a reference