The spins of compact objects born from helium stars in binary systems

Abstract

The angular momentum (AM) content of massive stellar cores helps to determine the natal spin rates of neutron stars and black holes. Asteroseismic measurements of low-mass stars have proven that stellar cores rotate slower than predicted by most prior work, so revised models are necessary. In this work, we apply an updated AM transport model based on the Tayler instability to massive helium stars in close binaries, in which tidal spin-up can greatly increase the star's AM. Consistent with prior work, these stars can produce highly spinning black holes upon core-collapse if the orbital period is less than P orb 1 day. For neutron stars, we predict a strong correlation between the pre-explosion mass and the neutron star rotation rate, with millisecond periods (P NS 5 ms) only achievable for massive (M 10 M ) helium stars in tight (P orb 1 day) binaries. Finally, we discuss our models in relation to type Ib/c supernovae, superluminous supernove, gamma-ray bursts, and LIGO measurements of black hole spins. Our models are roughly consistent with the rates and energetics of these phenomena, with the exception of broad-lined Ic supernovae, whose high rates and ejecta energies are difficult to explain.

Are binary black hole mergers and long gamma-ray bursts drawn from the same black hole population?

“…The core angular momentum has been transferred to the stellar envelope which has been ejected. This is the indication of an efficient transport of angular momentum in the progenitors of BBH mergers and possibly in most massive stars (Olejak & Belczynski 2021;Bavera et al 2022;Fuller & Lu 2022). If this scenario is correct, LGRBs, which require stellar cores with a large angular momentum at BH creation, cannot be emitted by single massive stars, nor by massive stars in wide binary systems.…”

Biases in estimates of black hole kicks from the spin distribution of binary black holes

“…Previous phases of mass transfer, tides and common envelope evolution are expected to have aligned the spins of the binary with the orbital angular momentum prior to this stage (e.g., Gerosa et al 2018). Tides exerted on the helium star by the black hole can lead to the rotation of the helium star becoming synchronised with the orbital period, potentially leading to a rapidly rotating helium star, that may subsequently collapse to form a rapidly rotating black hole (Detmers et al 2008;Kushnir et al 2016;Hotokezaka & Piran 2017;Zaldarriaga et al 2018;Qin et al 2018;Bavera et al 2020;Belczynski et al 2020;Steinle & Kesden 2021;Fuller & Lu 2022). Callister et al (2021) assume that this tidal spin up is possible for any orbital separation.…”

High magnetic field neutron stars and magnetars in binary systems

“…Progenitors of NSs can lose angular momentum via strong stellar winds, in addition they can significantly inflate on late evolutionary stages. If stellar cores (which later give birth to compact objects) are strongly coupled with envelopes, then it is difficult to expect very rapid rotation of NSs originated from isolated stars or in non-interacting binaries (see Postnov et al 2016 andFuller &Lu 2022 on core-envelope coupling and e.g., Langer et al 2008 and references therein on the role of rotation in massive star evolution, including binary evolution).…”

“…Fast rotation of a stellar core can be a result of evolution in a binary system (Fuller & Lu 2022, see, however, White et al 2022…”

“…There are three main routes to obtain a rapidly rotating core: angular momentum transfer via accretion, coalescence, and tidal synchronization. Popov & Prokhorov (2006) studied the role of the first two channels in production of highly magnetized NSs, and Bogomazov & Popov (2009) analysed the third one (see more recent and detailed calculations in Fuller & Lu 2022).…”