New ultracompact binaries comma new opportunities: the case for 1A 1246-588

1A 1246588 is a persistently accreting lowmass Xray binary at a distance of 5kpc and with an absorption of NH4E21 cm2. The persistent luminosity is virgul0.5%of the Eddington limit. This puts the source in an interesting accretion regime,possibly due to an ultracompact binary orbit. We propose to observe 1A1246588with XMMNewton and VLT/FORS2 to secure the suspected opticalcounterpart and ultracompact nature, carry out highresolution spectroscopy ofsuspected anomalous abundances of Ne, Fe and O with RGS and H, He, C and O withVLT/FORS2, and to search for an orbital period in the Xray lightcurve toinvestigate the evolutionary history of the binary. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]