scholarly journals Partly burned white dwarf survivors from peculiar thermonuclear supernovae

2021 ◽  
Author(s):  
Roberto Raddi
Keyword(s):  
White Dwarf ◽  
Thermonuclear Supernovae

scholarly journals Merging white dwarfs and thermonuclear supernovae

2013 ◽  
Vol 371 (1992) ◽  
pp. 20120236 ◽  
Author(s):  
M. H. van Kerkwijk
Keyword(s):  
White Dwarf ◽  
White Dwarfs ◽  
Nuclear Fusion ◽  
Thermonuclear Supernovae ◽  
Thermonuclear Runaway

Thermonuclear supernovae result when interaction with a companion reignites nuclear fusion in a carbon–oxygen white dwarf, causing a thermonuclear runaway, a catastrophic gain in pressure and the disintegration of the whole white dwarf. It is usually thought that fusion is reignited in near-pycnonuclear conditions when the white dwarf approaches the Chandrasekhar mass. I briefly describe two long-standing problems faced by this scenario, and the suggestion that these supernovae instead result from mergers of carbon–oxygen white dwarfs, including those that produce sub-Chandrasekhar-mass remnants. I then turn to possible observational tests, in particular, those that test the absence or presence of electron captures during the burning.

scholarly journals Pre-explosion Properties of Helium Star Donors to Thermonuclear Supernovae

2021 ◽  
Vol 922 (2) ◽  
pp. 241
Author(s):  
Tin Long Sunny Wong ◽  
Josiah Schwab ◽  
Ylva Götberg
Keyword(s):  
Stellar Evolution ◽  
White Dwarf ◽  
Stellar Atmosphere ◽  
Thermonuclear Supernovae ◽  
Atmosphere Model ◽  
Binary Evolution ◽  
Star Binary ◽  
Helium Star

Abstract Helium star–carbon-oxygen white dwarf (CO WD) binaries are potential single-degenerate progenitor systems of thermonuclear supernovae. Revisiting a set of binary evolution calculations using the stellar evolution code MESA, we refine our previous predictions about which systems can lead to a thermonuclear supernova and then characterize the properties of the helium star donor at the time of explosion. We convert these model properties to near-UV/optical magnitudes assuming a blackbody spectrum and support this approach using a matched stellar atmosphere model. These models will be valuable to compare with pre-explosion imaging for future supernovae, though we emphasize the observational difficulty of detecting extremely blue companions. The pre-explosion source detected in association with SN 2012Z has been interpreted as a helium star binary containing an initially ultra-massive WD in a multiday orbit. However, extending our binary models to initial CO WD masses of up to 1.2 M ⊙, we find that these systems undergo off-center carbon ignitions and thus are not expected to produce thermonuclear supernovae. This tension suggests that, if SN 2012Z is associated with a helium star–WD binary, then the pre-explosion optical light from the system must be significantly modified by the binary environment and/or the WD does not have a carbon-rich interior composition.

scholarly journals SDSS J124043.01+671034.68: the partially burned remnant of a low-mass white dwarf that underwent thermonuclear ignition?

2020 ◽  
Vol 496 (4) ◽  
pp. 4079-4086
Author(s):  
Boris T Gänsicke ◽  
Detlev Koester ◽  
Roberto Raddi ◽  
Odette Toloza ◽  
S O Kepler
Keyword(s):  
White Dwarf ◽  
Spectral Energy Distribution ◽  
Space Velocity ◽  
Spectral Energy ◽  
Galactic Rotation ◽  
Large Space ◽  
Upper Limits ◽  
Thermonuclear Supernovae ◽  
Low Mass ◽  
Far Ultraviolet

ABSTRACT The white dwarf SDSS J124043.01+671034.68 (SDSS J1240+6710) was previously found to have an oxygen-dominated atmosphere with significant traces of neon, magnesium, and silicon. A possible origin via a violent late thermal pulse or binary interactions has been suggested to explain this very unusual photospheric composition. We report the additional detection of carbon, sodium, and aluminium in far-ultraviolet and optical follow-up spectroscopy. No iron-group elements are detected, with tight upper limits on titanium, iron, cobalt, and nickel, suggesting that the star underwent partial oxygen burning, but failed to ignite silicon burning. Modelling the spectral energy distribution and adopting the distance based on the Gaia parallax, we infer a low white dwarf mass, $M_\mathrm{wd}=0.41\pm 0.05\, \mathrm{M}_\odot$. The large space velocity of SDSS J1240+6710, computed from the Gaia proper motion and its radial velocity, is compatible with a Galactic rest-frame velocity of ≃ 250 km s−1 in the opposite direction with respect to the Galactic rotation, strongly supporting a binary origin of this star. We discuss the properties of SDSS J1240+6710 in the context of the recently identified survivors of thermonuclear supernovae, the D6 and LP 40−365 stars, and conclude that it is unlikely related to either of those two groups. We tentatively suggest that SDSS J1240+6710 is the partially burned remnant of a low-mass white dwarf that underwent a thermonuclear event.

scholarly journals Heavy elements nucleosynthesis on accreting white dwarfs: building seeds for the p-process

2020 ◽  
Vol 497 (4) ◽  
pp. 4981-4998
Author(s):  
U Battino ◽  
M Pignatari ◽  
C Travaglio ◽  
C Lederer-Woods ◽  
P Denissenkov ◽  
...  
Keyword(s):  
White Dwarf ◽  
Stellar Structure ◽  
Neutron Density ◽  
Surface Layers ◽  
Near Surface ◽  
Main Site ◽  
Intermediate Neutron ◽  
Thermonuclear Supernovae ◽  
Long Time ◽  
High Neutron

ABSTRACT The origin of the proton-rich trans-iron isotopes in the Solar system is still uncertain. Single-degenerate thermonuclear supernovae (SNIa) with n-capture nucleosynthesis seeds assembled in the external layers of the progenitor’s rapidly accreting white dwarf (RAWD) phase may produce these isotopes. We calculate the stellar structure of the accretion phase of five white dwarf (WD) models with initial masses ≥ 0.85 $\, \mathrm{M}_\odot$ using the stellar code mesa The near-surface layers of the 1, 1.26, 1.32 and 1.38 $\, \mathrm{M}_\odot$ models are most representative of the regions in which the bulk of the p nuclei are produced during SNIa explosions, and for these models we also calculate the neutron-capture nucleosynthesis in the external layers. Contrary to previous RAWD models at lower mass, we find that the H-shell flashes are the main site of n-capture nucleosynthesis. We find high neutron densities up to several 1015 cm−3 in the most massive WDs. Through the recurrence of the H-shell flashes these intermediate neutron densities can be sustained effectively for a long time leading to high-neutron exposures with a strong production up to Pb. Both the neutron density and the neutron exposure increase with increasing the mass of the accreting WD. Finally, the SNIa nucleosynthesis is calculated using the obtained abundances as seeds. We obtain solar to supersolar abundances for p-nuclei with A > 96. Our models show that SNIa are a viable p-process production site.

scholarly journals Explosion Models for Thermonuclear Supernovae Resulting from Different Ignition Conditions

2005 ◽  
Vol 192 ◽  
pp. 339-344
Author(s):  
Eduardo Bravo ◽  
Domingo García-Senz
Keyword(s):  
White Dwarf ◽  
Three Dimensions ◽  
Thermonuclear Supernovae ◽  
Central Volume ◽  
The Mean

SummaryWe have explored in three dimensions the fate of a white dwarf of mass of 1.38 M⊙ as a function of different initial locations of carbon ignition, with the aid of a SPH code. The calculated models cover a variety of possibilities ranging from the simultaneous ignition of the central volume of the star to the off-center ignition in multiple scattered spots. In the former case, the possibility of a transition to a detonation when the mean density of the nuclear flame decreases to ρ ≃ 2 × 107 g cm−3 and its consequences are discussed. In the last case, the dependence of the results as a function of the number of initial igniting spots and the chance of some of these models to evolve to the pulsating delayed detonation scenario are also outlined.

Star reaches out to white dwarf

Nature ◽  
2005 ◽  
Author(s):  
Roxanne Khamsi
Keyword(s):  
White Dwarf

Stellar Masses, Kinematics, and White Dwarf Composition for Three Close DA+dMe Binaries

1999 ◽  
Vol 523 (1) ◽  
pp. 386-398 ◽  
Author(s):  
Stephane Vennes ◽  
John R. Thorstensen ◽  
Elisha F. Polomski
Keyword(s):  
White Dwarf ◽  
Stellar Masses

Discovery of a Magnetic White Dwarf in the Symbiotic Binary Z Andromedae

1999 ◽  
Vol 517 (2) ◽  
pp. 919-924 ◽  
Author(s):  
J. L. Sokoloski ◽  
Lars Bildsten
Keyword(s):  
White Dwarf
Sign in / Sign up

Export Citation Format

Share Document