Binary-binary interactions and the formation of the PSR B1620-26 triple system in M4

Frederic A. Rasio*, Steve Mcmillan, Piet Hut

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


The hierarchical triple system containing the millisecond pulsar PSR B1620-26 in M4 is the first triple star system ever detected in a globular cluster. Such systems should form in globular clusters as a result of dynamical interactions between binaries. We propose that the triple system containing PSR B1620-26 formed through an exchange interaction between a wide primordial binary and a pre-existing binary millisecond pulsar. This scenario would have the advantage of reconciling the ∼109 yr timing age of the pulsar with the much shorter lifetime of the triple system in the core of M4.

Original languageEnglish (US)
Pages (from-to)L33-L36
JournalAstrophysical Journal
Issue number1 PART 2
StatePublished - Jan 1 1995


  • Celestial mechanics, stellar dynamics
  • Globular clusters: general
  • Globular clusters: individual (M4)
  • Pulsars: individual (PSR B1620-26)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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