2014/10/21 by Takashi J. Moriya, Norbert Langer, N. Langer
Physics and Astronomy · #Astronomy #Astrophysics #Gamma-ray bursts and supernovae #Instability #Mechanics #Physics #Pulsars and Gravitational Waves Research #Red supergiant #Stars #Stellar, planetary, and galactic studies #Supergiant #Supernova #astro-ph.SR
paper · pdf · doi:10.1051/0004-6361/201424957
published as Astronomy & Astrophysics, Volume 573, id.A18, 11 pp. (2015) · 11 pages, 10 figures, 1 table, accepted by Astronomy & Astrophysics, proofed in v2
openalex publication_date 2014/10/21 · arxiv created 2014/11/12 · arxiv updated 2014/12/16 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Recent stellar evolution models show consistently that very massive metal-free stars evolve into red supergiants shortly before they explode. We argue that the envelopes of these stars, which will form pair-instability supernovae, become pulsationally unstable and that this will lead to extreme mass-loss rates despite the tiny metal content of the envelopes. We investigate the pulsational properties of such models and derive pulsationally induced mass-loss rates, which take the damping effects of the mass loss on the pulsations selfconsistently into account. We find that the pulsations may induce mass-loss rates of ~10-4 − 10-2M⊙ yr-1 shortly before the explosions, which may create a dense circumstellar medium. Our results show that very massive stars with dense circumstellar media may stem from a wider initial mass range than pulsational-pair instability supernovae. The extreme mass loss will cease when so much of the hydrogen-rich envelope is lost that the star becomes more compact and stops pulsating. The helium core of these stars therefore remains unaffected, and their fate as pair-instability supernovae remains unaltered. The existence of dense circumstellar media around metal-free pair-instability supernovae can make them brighter and bluer, and they may be easier to detect at high redshifts than previously expected. We argue that the mass-loss enhancement in pair-instability supernova progenitors can naturally explain some observational properties of superluminous supernovae: the energetic explosions of stars within hydrogen-rich dense circumstellar media with little 56Ni production and the lack of a hydrogen-rich envelope in pair-instability supernova candidates with large 56Ni production.