The origin of planets orbiting millisecond pulsars

Marco Tavani & Leigh Brookshaw

26 March 1992
Published in Nature 1992 356, pp. 320-322

Abstract:

At least two Earth-sized planets have been discovered around the Ems pulsar PSR1257+12 [1], which, like millisecond pulsars in general, has probably been spun up by accretion of material from a companion star. In addition, two 'star-vaporizing' milli- second pulsars (SVPs), l957+20 [2] and 1744-24A [3,4], show evidence of mass outflows from their low-mass companions, which are thought to be vaporized by pulsar radiation. Building on this, we suggest a model for the formation of planets around millisecond pulsars such as 1257+12, which no longer have stellar companions. We present detailed hydrodynamical models which suggest that planet formation can occur either in a low-mass X-ray binary progenitor to a progenitor of an SVP when the neutron star is accreting material driven off its companion by X-ray irradiation [5,6], or after a pulsar has formed and is vaporizing its companion [5,7,8,9]. In both cases a circum-binary disk is created in which planets can form on a timescale of [10] (which is short compared with the binary evolution timescales of the parent systems) and the planets can survive a second phase in which the companion star moves towards the pulsar and is completely vaporized [5].

• Introduction
• Numerical Method
• Star Vaporising Pulsars (SVPs)
• Low-Mass X-ray Binaries
• Conclusion
• References
• About this document ...