A 110-ms pulsar, with negative period derivative, in the globular cluster M15

A. Wolszczan, S. R. Kulkarni, J. Middleditch, D. C. Backer, A. S. Fruchter, R. J. Dewey

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We report the discovery of a 110-ms pulsar, PSR2127 + 11, in the globular cluster M15 (NGC7078)1. The results of nine months of timing measurements place the new pulsar about 2″ from the centre of the cluster, and indicate that it is not a member of a close binary system. The measured negative value of the period derivative, P ≈ -2 × 10-17 s s-1, is probably the result of the pulsar being bodily accelerated in our direction by the gravitational field of the collapsed core of M15. This apparently overwhelms a positive contribution to Ṗ due to magnetic braking. Although PSR2127 + 11 has an unexpectedly long period, we argue that it belongs to the class of 'recycled' pulsars, which have been spun up by accretion in a binary system. The subsequent loss of the pulsar's companion is probably due to disruption of the system by close encounters with other stars2,3.

Original languageEnglish (US)
Pages (from-to)531-533
Number of pages3
Issue number6207
StatePublished - Jan 1 1989


All Science Journal Classification (ASJC) codes

  • General

Cite this

Wolszczan, A., Kulkarni, S. R., Middleditch, J., Backer, D. C., Fruchter, A. S., & Dewey, R. J. (1989). A 110-ms pulsar, with negative period derivative, in the globular cluster M15. Nature, 337(6207), 531-533. https://doi.org/10.1038/337531a0