P. R. Brook^1,5, A. Karastergiou¹, S. Buchner^2,6, S. J. Roberts³, M. J. Keith^4,7, S. Johnston⁴ and R. M. Shannon⁴

¹Astrophysics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH, UK
²Hartebeesthoek Radio Astronomy Observatory, P.O. Box 443, Krugersdorp 1740, South Africa
³Information Engineering, University of Oxford, Parks Road, Oxford OX1 3PJ, UK
⁴CSIRO Astronomy and Space Science, Australia Telescope National Facility, P.O. Box 76, Epping, NSW 1710, Australia
⁵CSIRO Astronomy and Space Science, Australia Telescope National Facility, P.O. Box 76, Epping, NSW 1710, Australia
⁶School of Physics, University of Witwatersrand, Johannesburg, South Africa
⁷Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK

Debris disks and asteroid belts are expected to form around young pulsars due to fallback material from their original supernova explosions. Disk material may migrate inward and interact with a pulsar’s magnetosphere, causing changes in torque and emission. Long-term monitoring of PSR J0738–4042 reveals both effects. The pulse shape changes multiple times between 1988 and 2012. The torque, inferred via the derivative of the rotational period, changes abruptly from 2005 September. This change is accompanied by an emergent radio component that drifts with respect to the rest of the pulse. No known intrinsic pulsar processes can explain these timing and radio emission signatures. The data lead us to postulate that we are witnessing an encounter with an asteroid or in-falling debris from a disk.

Reference
Brook PR, Karastergiou A, Buchner S, Roberts SJ, Keith MJ, Johnston S and Shannon RM (2014) Evidence of an Asteroid Encountering a Pulsar. The Astrophysical Journal – Letters 780:L31.
[doi:10.1088/2041-8205/780/2/L31]

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