X-ray lines and magnetic field of Her X-1

K. Brecher*, M. P. Ulmer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


THE report1 of a possible detection of an X-ray emission line with energy about 53 keV from the binary X-ray source Her X-1 created great excitement. Interpreting the line as arising from non-relativistic electron cyclotron emission at the surface of an accreting neutron star member of the binary star system, Trumper et al.1 deduce a neutron star surface magnetic field of 4.6 × 1012 G. If the line is real (of cosmic origin and not due to background effects), significant (not due to a statistical fluctuation) and correctly interpreted as arising from non-relativistic cyclotron emission) it could provide the first direct and quantitative measure of the magnetic field of a neutron star, and be direct support for our ideas on the formation of neutron stars and the role of magnetic fields in the radiation mechanisms of pulsars and binary X-ray sources. Furthermore, it would conclusively rule out the possibility that Her X-1 contains a rotating or pulsating white dwarf (which, for dynamical stability requires B≪G 1/2MR-2≃1012G for M≃M and R=RWD≃ 109 cm).

Original languageEnglish (US)
Pages (from-to)135-137
Number of pages3
Issue number5641
StatePublished - 1978

ASJC Scopus subject areas

  • General


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