Tidal breakup of quadruple stars in the Galactic Centre

The most likely origin of hypervelocity stars is the tidal disruption of a binary star by the supermassive black hole (MBH) in the Galactic Centre (GC). However, HE0437-5439, a 9M(circle dot) B-type main-sequence star moving with a heliocentric radial velocity of about 720 km s(-1) at a distance of similar to 60 kpc, and the recent discovered hypervelocity binary candidate (HVB), travelling at similar to 570 km s(-1), challenge this standard scenario. Recently, Fragione & Gualandris have demonstrated that the tidal breakup of a triple star leads to an insufficient rate. Observations show that quadruple stars made up of two binaries orbiting their common centre of mass (the so-called 2+2 quadruples) are approximate to 4 per cent of the stars in the solar neighbourhood. Although rarer than triples, 2+2 quadruple stars may have a role in ejecting HVBs as due to their larger energy reservoir. We present a numerical study of 2+2 quadruple disruptions by the MBH in the GC and find that the production of HVBs has a probability less than or similar to 2-4 per cent, which translates into an ejection rate of less than or similar to 1Gyr(-1), comparable to the triple disruption scenario. Given the low-ejection rate, we suggest that alternative mechanisms are responsible for the origin of HVBs, as the ejection from the interaction of a young star cluster with the MBH in the GC and the origin in the Large Magellanic Cloud.