SUB-CHANDRASEKHAR WHITE DWARF MERGERS AS THE PROGENITORS OF TYPE Ia SUPERNOVAE

By M. V. van Kerkwijk, P. Chang, S. Justham. 2010

139 citations recorded by the source corpus.

Type Ia supernovae (SNe Ia) are generally thought to be due to the thermonuclear explosions of carbon–oxygen white dwarfs (CO WDs) with masses near the Chandrasekhar mass. This scenario, however, has two long-standing problems. First, the explosions do not naturally produce the correct mix of elements, but have to be finely tuned to proceed from subsonic deflagration to supersonic detonation. Second, population models and observations give formation rates of near-Chandrasekhar WDs that are far too small. Here, we suggest that SNe Ia instead result from mergers of roughly equal-mass CO WDs, including those that produce sub-Chandrasekhar mass remnants. Numerical studies of such mergers have shown that the remnants consist of rapidly rotating cores that contain most of the mass and are hottest in the center, surrounded by dense, small disks. We argue that the disks accrete quickly, and that the resulting compressional heating likely leads to central carbon ignition. This ignition occurs at densities for which pure detonations lead to events similar to SNe Ia. With this merger scenario, we can understand the type Ia rates and have plausible reasons for the observed range in luminosity and for the bias of more luminous supernovae toward younger populations. We speculate that explosions of WDs slowly brought to the Chandrasekhar limit—which should also occur—are responsible for some of the “atypical” SNe Ia.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/2a912994c101d59b76e58dc992b7470896be8d44

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Citations in the corpus

• THE LONG-TERM EVOLUTION OF DOUBLE WHITE DWARF MERGERS (2011, background): “…use throughout this paper, these studies have found that both components, instead of just one, are tidally disrupted (Lorén-Aguilar et al. 2009; van Kerkwijk et al. 2010) or that the resulting merger is more violent and reaches higher temperatures than in the unequal mass case (Pakmor et al.…”
• ACCELERATING COMPACT OBJECT MERGERS IN TRIPLE SYSTEMS WITH THE KOZAI RESONANCE: A MECHANISM FOR “PROMPT” TYPE Ia SUPERNOVAE, GAMMA-RAY BURSTS, AND OTHER EXOTICA (2010, background): “If sub-Chandrasekhar mass binaries can contribute to the Ia rate (e.g., van Kerkwijk et al. 2010), the IMF implies that a still smaller fraction of all stars produce Ia’s.”
• The delay-time distribution of Type Ia supernovae from Sloan II (2012, background): “CO WD mergers can indeed produce a SN Ia, which is still an open question (e.g. Guillochon et al. 2010; van Kerkwijk et al. 2010; Pakmor et al. 2011).”
• Type-Ia Supernova Rates and the Progenitor Problem: A Review (2011, background): “In sub-Chandra merger SN Ia models (Sim et al. 2010; Van Kerkwijk et al. 2010; Ruiter et al. 2011), involving the mergers of white dwarfs that had main sequence masses smaller than 3M⊙, tc would shift to longer delays .”
• Supernova Type Ia progenitors from merging double white dwarfs - Using a new population synthesis model (2012, methodology): “The rates of the channel proposed by van Kerkwijk et al. (2010) for systems with sub-Chandrasekhar masses are on the same order of magnitude as the rates of the standard DWD channel.”
• THE SUPERNOVA DELAY TIME DISTRIBUTION IN GALAXY CLUSTERS AND IMPLICATIONS FOR TYPE-Ia PROGENITORS AND METAL ENRICHMENT (2010, background): “A, et al. 2009, Sceince, 325, 719 Hicks, A. K., et al. 2008, ApJ, 680, 1022 Hoyle, F., & Fowler, W. A. 1960, ApJ, 132, 565 Iben, I., Jr., & Tutukov, A. V. 1984, ApJS, 54, 335 Jorgensen, H. E., Lipunov, V. M., Panchenko, I. E., Postnov, K. A., & Prokhorov, M. E. 1997, ApJ, 486, 110 Kauffmann, G., et ”
• A circumbinary disc in the final stages of common envelope and the core-degenerate scenario for Type Ia supernovae (2011, background): “In the model of van Kerkwijk et al. (2010) the disk accretes at a high rate that leads to compressional heating that is likely to cause central carbon ignition.”