Journal Article

The mass of the neutron star in the binary millisecond pulsar PSR J1012 + 5307

Paul J. Callanan, Peter M. Garnavich and Detlev Koester

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 298, issue 1, pages 207-211
Published in print July 1998 | ISSN: 0035-8711
Published online July 1998 | e-ISSN: 1365-2966 | DOI:
The mass of the neutron star in the binary millisecond pulsar PSR J1012 + 5307

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We have measured the radial velocity variation of the white dwarf secondary in the binary system containing the millisecond pulsar PSR J 1012 + 5307. Combined with the orbital parameters of the radio pulsar, we infer a mass ratio q (≡M1/M2) = 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 M2 = 0.16 ± 0.02 M⊙, and hence the mass of the neutron star is 1.64 ± 0.22 M, where the error is dominated by that of M2. The orbital inclination is 52 ± 4°. For an initial neutron star mass of ∼ 1.4 M, 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 ∼ 1 M, our result suggests that the mass transfer may have been non-conservative.

Keywords: stars: binaries: general; neutron; pulsars: individual: PSR J 1012 ± 5307

Journal Article.  0 words. 

Subjects: Astronomy and Astrophysics

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