Ultracompact X-Ray Binaries with Neon-Rich Degenerate Donors

Adrienne M. Juett, Dimitrios Psaltis, Deepto Chakrabarty

There are three low-mass X-ray binaries (4U 0614+091, 2S 0918-549, and 4U 1543-624) for which broad line emission near 0.7 keV was previously reported. A recent high-resolution obs…