2016/06/28 by Jordi Casanova, J. José, Casanova, Jordi +5 · 2 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysical Phenomena and Observations #Atomic and Molecular Physics #FOS: Physical sciences #High-pressure geophysics and materials #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.1606.08734
openalex publication_date 2016/06/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Classical novae are thermonuclear explosions that take place in the envelopes\nof accreting white dwarfs in binary systems. The material piles up under\ndegenerate conditions, driving a thermonuclear runaway. The energy released by\nthe suite of nuclear processes operating at the envelope heats the material up\nto peak temperatures about 100 - 400 MK. During these events, about 10-3 - 10-7\nMsun, enriched in CNO and, sometimes, other intermediate-mass elements (e.g.,\nNe, Na, Mg, Al) are ejected into the interstellar medium. To account for the\ngross observational properties of classical novae (in particular, the large\nconcentrations of metals spectroscopically inferred in the ejecta), models\nrequire mixing between the (solar-like) material transferred from the secondary\nand the outermost layers (CO- or ONe-rich) of the underlying white dwarf.\nRecent multidimensional simulations have demonstrated that Kelvin-Helmholtz\ninstabilities can naturally produce self-enrichment of the accreted envelope\nwith material from the underlying white dwarf at levels that agree with\nobservations. However, the feasibility of this mechanism has been explored in\nthe framework of CO white dwarfs, while mixing with different substrates still\nneeds to be properly addressed. Three-dimensional simulations of mixing at the\ncore-envelope interface during nova outbursts have been performed with the\nmultidimensional code FLASH, for two types of substrates: CO- and ONe-rich. We\nshow that the presence of an ONe-rich substrate, as in "neon novae", yields\nlarger metallicity enhancements in the ejecta, compared to CO,rich substrates\n(i.e., non-neon novae). A number of requirements and constraints for such 3-D\nsimulations (e.g., minimum resolution, size of the computational domain) are\nalso outlined.\n