Trompe l'oeil "binary" pulsars

Robert W. Nelson, Lee S. Finn, Ira Wasserman

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


We show that a freely processing pulsar produces pulse phase residuals which can mimic those of a pulsar in a binary orbit. In particular, we sample discrete sets of phase residuals due to precessional motion of an isolated pulsar, and show that this data is well fit by residuals from a binary pulsar in a sufficiently tight orbit. We find analytic and numerical relationships between the projected orbital size, ap sin i, and the orbital eccentricity, e, of a misidentified binary pulsar and discuss the observations that would distinguish between these models. Regardless of the mechanism that causes the precession, the maximum amplitude of the phase residual is π/2: consequently, ap sin i is (approximately) bounded by cPpuls/4. We discuss the newly discovered "binary" millisecond pulsars in the globular cluster 47 Tuc and in the remnant of SN 1987A, and show that the periodic frequency modulation reported for these pulsars cannot be explained by free precession.

Original languageEnglish (US)
Pages (from-to)226-231
Number of pages6
JournalAstrophysical Journal
Issue number1
StatePublished - Jan 1 1990

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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