The progenitor of binary millisecond radio pulsar PSR J1713+0747

W. C. CHEN; J. A. PANEI

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Año: 2011 vol. 527 p. 128 - 133

0004-6361

Context: PSR J1713+0747 is a binary system comprising millisecond radio pulsar with a spin period of 4.57 ms, and a low-mass white dwarf (WD) companion orbiting the pulsar with a period of 67.8 days. Using the general relativistic Shapiro delay, the masses of the WD and pulsar components were previously found to be 0.28 +/- 0.03 M_sun and 1.3 +/- 0.2 M_sun (68% confidence), respectively.Aims: Standard binary evolution theory suggests that PSR J1713+0747 evolved from a low-mass X-ray binary (LMXB). Here, we test this hypothesis.Methods:  We used a binary evolution code and a WD evolution code to calculate evolutionary sequences of LMXBs that could result in binary millisecond radio pulsars such as PSR J1713+0747.Results:During the mass exchange, the mass transfer is nonconservative.Because of the thermal and viscous instabilities developing in theaccretion disk, the neutron star accretes only a small part of theincoming material. We find that the progenitor of PSR J1713+0747 can be modelled as an LMXB including a donor star with mass 1.3-1.6 M_sun and an initial orbital period ranging from 2.40 to 4.15 days. If the cooling timescale of the WD is 8 Gyr, its present effectivetemperature is between 3870 and 4120 K, slightly higher than theobserved value. We estimate a surface gravity of Log(g) aprox7.38-7.40.