Journal
ASTRONOMY & ASTROPHYSICS
Volume 403, Issue 3, Pages 1067-1075Publisher
EDP SCIENCES S A
DOI: 10.1051/0004-6361:20030384
Keywords
pulsars : individual : PSR J0218+4232; stars : neutron; stars : white dwarfs
Categories
Ask authors/readers for more resources
We report on Keck optical BVRI images and spectroscopy of the companion of the binary millisecond pulsar PSR J0218+4232. A faint bluish (V = 24.2, B-V = 0.25) counterpart is observed at the pulsar location. Spectra of this counterpart reveal Balmer lines which confirm that the companion is a helium-core white dwarf. We find that the white dwarf has a temperature of T-eff = 8060 +/- 150 K. Unfortunately, the spectra are of insufficient quality to put a strong constraint on the surface gravity, although the best fit is for low log g and hence low mass (similar to0.2 M-circle dot), as expected. We compare predicted white dwarf cooling ages with the characteristic age of the pulsar and find similar values for white dwarf masses of 0.19 to 0.3 M-circle dot. These masses would imply a distance of 2.5 to 4 kpc to the system. The spectroscopic observations also enable us to estimate the mass ratio between the white dwarf and the pulsar. We find q = 7.5 +/- 2.4, which is consistent with the current knowledge of white dwarf companions to millisecond pulsars.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available