2025/05/13 by Ruggero Valli, Valli, Ruggero, S. E. de Mink +17
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #FOS: Physical sciences #Gamma-ray bursts and supernovae #High Energy Astrophysical Phenomena (astro-ph.HE) #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.2505.08857
openalex publication_date 2025/05/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Supernovae, the explosive deaths of massive stars, create heavy elements and form black holes and neutron stars. These compact objects often receive a velocity at formation, a "kick" whose physical origin remains debated. We investigate kicks in Be X-ray binaries, containing a neutron star and a rapidly spinning companion. We identify two distinct populations: one with kicks below 10 \rmkm \rms-1, much lower than theoretical predictions, and another with kicks around 100 \rmkm \rms-1, that shows evidence for being aligned within 5 degrees of the progenitor's rotation axis. The distribution of progenitor masses for the two populations have medians around 2.3 \rmM_\odot and 4.9 \rmM_\odot, corresponding to stars with birth masses of about 10 \rmM_\odot and 15 \rmM_\odot. The second component matches the low-velocity mode observed in isolated pulsars. Combined with the known high-velocity component, which dominates isolated pulsars, this suggests three distinct kick modes. These results reveal previously unrecognized diversity in neutron-star formation.