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arXiv · 1307.3258

The Runaway Binary LP 400-22 is Leaving the Galaxy

Mukremin Kilic·A. Gianninas·Warren R. Brown·Hugh C. Harris·Conard C. Dahn·M. A. Agueros·Craig O. Heinke·S. J. Kenyon·J. A. Panei·Fernando Camilo
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Abstract

We present optical spectroscopy, astrometry, radio, and X-ray observations of the runaway binary LP 400-22. We refine the orbital parameters of the system based on our new radial velocity observations. Our parallax data indicate that LP 400-22 is significantly more distant (3 sigma lower limit of 840 pc) than initially predicted. LP 400-22 has a tangential velocity in excess of 830 km/s; it is unbound to the Galaxy. Our radio and X-ray observations fail to detect a recycled millisecond pulsar companion, indicating that LP 400-22 is a double white dwarf system. This essentially rules out a supernova runaway ejection mechanism. Based on its orbit, a Galactic center origin is also unlikely. However, its orbit intersects the locations of several globular clusters; dynamical interactions between LP 400-22 and other binary stars or a central black hole in a dense cluster could explain the origin of this unusual binary.

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Mukremin Kilic, A. Gianninas, Warren R. Brown, Hugh C. Harris, Conard C. Dahn, M. A. Agueros, Craig O. Heinke, S. J. Kenyon, J. A. Panei, Fernando Camilo. 2013-07-11. The Runaway Binary LP 400-22 is Leaving the Galaxy. https://doi.org/10.1093/mnras/stt1282

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