The mass of the neutron star in the binary millisecond pulsar PSR J1012+5307
Abstract
We have measured the radial velocity variation of the white dwarf secondary in the binary system containing the millisecond pulsar PSR J1012+5307. Combined with the orbital parameters of the radio pulsar, we infer a mass ratio q (=M_1/M_2)=10.5+/-0.5. Our optical spectroscopy has also allowed us to determine the mass of the white dwarf companion by fitting the spectrum to a grid of DA model atmospheres: we estimate M_2=0.16+/-0.02Msolar, and hence the mass of the neutron star is 1.64+/-0.22Msolar, where the error is dominated by that of M_2. The orbital inclination is 52+/-4 deg. For an initial neutron star mass of ~1.4Msolar, only a few tenths of a solar mass at most has been successfully accreted over the lifetime of the progenitor low-mass X-ray binary. If the initial mass of the secondary was ~1Msolar, our result suggests that the mass transfer may have been non-conservative.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 1998
- DOI:
- 10.1046/j.1365-8711.1998.01634.x
- Bibcode:
- 1998MNRAS.298..207C
- Keywords:
-
- STARS: BINARIES: GENERAL;
- NEUTRON;
- PULSARS: INDIVIDUAL: PSR J1012+/-5307