Low mass X-ray binaries with pre-main sequence companions

Abstract

In this Letter we examine the idea that a subset of short-period black-hole low-mass X-ray binaries could be powered by the mass transfer from pre-main sequence donors. As the star contracts towards the main sequence, the strong magnetic fields operate the magnetic braking which dissipates the orbital angular momentum, driving the binary to contact. We show that the periods and apparent donor spectral classes of the X-ray binaries with a pre-main sequence donor agree better with the available observations of black hole X-ray binaries than those of binaries with a main-sequence donor. This mechanism also explains, without the need for additional hypotheses, the roughly primordial abundance of Li detected in donor companions of black hole X-ray candidates in our Galaxy.

4 pages in emuapj style, 3 fugures, to appear in ApJL

References in corpus (4)

• X-ray Properties of Black-Hole Binaries
• T Tauri stellar magnetic fields: He I measurements
• Synchrotron emission from the T Tauri binary system V773 Tau A
• Evidence for T Tauri-like emission in the EXor V1118 Ori from near-IR and X-ray data

Cited by in corpus (3)

• The isotopic 6Li/7Li ratio in Cen X-4 and the origin of Li in X-ray binaries
• Globular Clusters and X-ray Point Sources in Centaurus A (NGC 5128)
• Aspherical supernova explosions and formation of compact black hole low-mass X-ray binaries