http://arxiv.org/abs/2006.06389
Some massive stars experience episodic and intense mass loss phases with fluctuations in the luminosity. Ejected material forms circumstellar matter (CSM) around the star, and the subsequent core-collapse results in a type IIn supernova which is characterized by interaction between supernova ejecta and the CSM. The energy source which triggers these mass eruptions and dynamics of the outflow have not been clearly explained. Moreover, the mass eruption itself can alter the density structure of the envelope and affect the dynamics of the subsequent mass eruption if these events repeat. In fact, a large amount of observational evidence suggests multiple mass eruptions prior to core-collapse. We investigate the density structure of the envelope altered by the first mass eruption and the nature of the subsequent second mass eruption event in comparison with the first one. We deposited an extra energy twice at the bottom of the hydrogen envelope and calculate the time evolution by our radiation hydrodynamical simulation code. We do not deal with the origin of the energy source but focus on the dynamics of repeated mass eruptions from a single massive star. There are significant differences between the first and second mass eruptions in terms of the luminosity, color, amount of produced CSM. The second eruption leads to a redder burst event with the associated brightening phase lasting longer than the first one. The amount of ejected matter is different even with the same deposited energy in the first and second event, but the difference depends on the density structure of the progenitor star. Upcoming high cadence and deep transient surveys will provide us a lot of detailed pre-supernova activities, and some of them would show multi-peaked light curves. They should be interpreted taking the effect of density structure altered by the preceding outburst events into consideration.
N. Kuriyama and T. Shigeyama
Fri, 12 Jun 20
43/69
Comments: 8 pages, 10 figures, 3 tables, submitted to A&A, Abstract is slightly abridged from A&A submitted version because it exceeds 1920 characters
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