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Astron. Astrophys. 356, 929-934 (2000)

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The evolution of helium white dwarfs

III. On the ages of millisecond pulsar systems

D. Schönberner 1, T. Driebe 2 and T. Blöcker 2

1 Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany (deschoenberner@aip.de)
2 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany (driebe@mpifr-bonn.mpg.de; bloecker@mpifr-bonn.mpg.de)

Received 4 November 1999 / Accepted 3 February 2000


We employed recently computed evolutionary white-dwarf models with helium cores, supplemented by heavier models with carbon-oxygen cores, in order to investigate the ages of millisecond pulsar systems based on the cooling properties of the compact companions. Contrary to the behaviour of more massive white dwarfs, the evolutionary speed of low-mass white-dwarf models is substantially slowed down by ongoing hydrogen burning. By comparing the cooling ages of these models with the spin-down ages of the pulsars for those systems for which reasonable information about the compact companions is available, we found good correspondence between both ages. Based on these models any revisions concerning the temporal evolution of millisecond pulsars do not appear to be necessary.

Key words: stars: evolution – stars: white dwarfs – stars: pulsars: general

Send offprint requests to: D. Schönberner

© European Southern Observatory (ESO) 2000

Online publication: April 17, 2000