There is building evidence that the first stars are not as massive as previously thought and that they are merely typical massive stars on the order of tens of solar masses instead of behemoths up to 300 solar masses.  Furthermore, a non-negligible fraction of this population form in binary systems. These stellar systems can leave behind stellar-mass black holes, chemically enriched regions from their supernovae, and X-ray binaries if the companion star overflows onto the black hole during its giant phase. All of this depends on the initial mass function of the first stars, which is highly uncertain at the moment, but luckily it’s an active area of research!

To determine the evolution and impact of these remnants, we must know where they migrate after their progenitor star dies.  This week, Hao Xu, Michael Norman at UCSD and I submitted a paper that focuses on exactly this point. Continue reading New paper: The remnants of the first stars →