TY - JOUR

T1 - Common envelope episodes that lead to double neutron star formation

AU - Vigna-Gomez, Alejandro

AU - MacLeod, Morgan

AU - Neijssel, Coenraad J.

AU - Broekgaarden, Floor S.

AU - Justham, Stephen

AU - Howitt, George

AU - de Mink, Selma E.

AU - Vinciguerra, Serena

AU - Mandel, Ilya

PY - 2020/9/23

Y1 - 2020/9/23

N2 - Close double neutron stars (DNSs) have been observed as Galactic radio pulsars, while their mergers have been detected as gamma-ray bursts and gravitational wave sources. They are believed to have experienced at least one common envelope episode (CEE) during their evolution prior to DNS formation. In the last decades, there have been numerous efforts to understand the details of the common envelope (CE) phase, but its computational modelling remains challenging. We present and discuss the properties of the donor and the binary at the onset of the Roche lobe overflow (RLOF) leading to these CEEs as predicted by rapid binary population synthesis models. These properties can be used as initial conditions for detailed simulations of the CE phase. There are three distinctive populations, classified by the evolutionary stage of the donor at the moment of the onset of the RLOF: giant donors with fully convective envelopes, cool donors with partially convective envelopes, and hot donors with radiative envelopes. We also estimate that, for standard assumptions, tides would not circularise a large fraction of these systems by the onset of RLOF. This makes the study and understanding of eccentric mass-transferring systems relevant for DNS populations.

AB - Close double neutron stars (DNSs) have been observed as Galactic radio pulsars, while their mergers have been detected as gamma-ray bursts and gravitational wave sources. They are believed to have experienced at least one common envelope episode (CEE) during their evolution prior to DNS formation. In the last decades, there have been numerous efforts to understand the details of the common envelope (CE) phase, but its computational modelling remains challenging. We present and discuss the properties of the donor and the binary at the onset of the Roche lobe overflow (RLOF) leading to these CEEs as predicted by rapid binary population synthesis models. These properties can be used as initial conditions for detailed simulations of the CE phase. There are three distinctive populations, classified by the evolutionary stage of the donor at the moment of the onset of the RLOF: giant donors with fully convective envelopes, cool donors with partially convective envelopes, and hot donors with radiative envelopes. We also estimate that, for standard assumptions, tides would not circularise a large fraction of these systems by the onset of RLOF. This makes the study and understanding of eccentric mass-transferring systems relevant for DNS populations.

KW - binaries

KW - common envelope

KW - mass transfer

KW - neutron stars

KW - population synthesis

KW - CONSERVATIVE MASS-TRANSFER

KW - SECULAR ORBITAL EVOLUTION

KW - TIDAL CAPTURE BINARIES

KW - X-RAY

KW - INTERACTING BINARIES

KW - BLACK-HOLE

KW - POPULATION SYNTHESIS

KW - ECCENTRIC BINARIES

KW - STELLAR EVOLUTION

KW - DYNAMICAL TIDES

U2 - 10.1017/pasa.2020.31

DO - 10.1017/pasa.2020.31

M3 - Journal article

VL - 37

JO - Publications of the Astronomical Society of Australia

JF - Publications of the Astronomical Society of Australia

SN - 1448-6083

M1 - 038

ER -