scholarly journals Three Hypervelocity White Dwarfs in Gaia DR2: Evidence for Dynamically Driven Double-degenerate Double-detonation Type Ia Supernovae

2018 ◽  
Vol 865 (1) ◽  
pp. 15 ◽  
Author(s):  
Ken J. Shen ◽  
Douglas Boubert ◽  
Boris T. Gänsicke ◽  
Saurabh W. Jha ◽  
Jennifer E. Andrews ◽  
...  
1994 ◽  
Vol 147 ◽  
pp. 186-213
Author(s):  
J. Isern ◽  
R. Canal

AbstractIn this paper we review the behavior of growing stellar degenerate cores. It is shown that ONeMg white dwarfs and cold CO white dwarfs can collapse to form a neutron star. This collapse is completely silent since the total amount of radioactive elements that are expelled is very small and a burst of γ-rays is never produced. In the case of an explosion (always carbonoxygen cores), the outcome fits quite well the observed properties of Type Ia supernovae. Nevertheless, the light curves and the velocities measured at maximum are very homogeneous and the diversity introduced by igniting at different densities is not enough to account for the most extreme cases observed. It is also shown that a promising way out of this problem could be the He-induced detonation of white dwarfs with different masses. Finally, we outline that the location of the border line which separetes explosion from collapse strongly depends on the input physics adopted.


2021 ◽  
Vol 919 (2) ◽  
pp. 126
Author(s):  
Samuel J. Boos ◽  
Dean M. Townsley ◽  
Ken J. Shen ◽  
Spencer Caldwell ◽  
Broxton J. Miles

2004 ◽  
Vol 194 ◽  
pp. 111-112
Author(s):  
Lilia Ferrario

AbstractI argue that the observational evidence for white dwarf-white dwarf mergers supports the view that they give rise to ultra-massive white dwarfs or neutron stars through accretion induced collapse. The implications for the progenitors of Type Ia SNe are discussed.


2020 ◽  
Vol 497 (2) ◽  
pp. 1895-1903 ◽  
Author(s):  
E C Wilson ◽  
J Nordhaus

ABSTRACT The formation channels and predicted populations of double white dwarfs (DWDs) are important because a subset will evolve to be gravitational-wave sources and/or progenitors of Type Ia supernovae. Given the observed population of short-period DWDs, we calculate the outcomes of common envelope (CE) evolution when convective effects are included. For each observed white dwarf (WD) in a DWD system, we identify all progenitor stars with an equivalent proto-WD core mass from a comprehensive suite of stellar evolution models. With the second observed WD as the companion, we calculate the conditions under which convection can accommodate the energy released as the orbit decays, including (if necessary) how much the envelope must spin-up during the CE phase. The predicted post-CE final separations closely track the observed DWD orbital parameter space, further strengthening the view that convection is a key ingredient in CE evolution.


2016 ◽  
Vol 26 (1) ◽  
Author(s):  
Dongdong Liu ◽  
Bo Wang ◽  
Chengyuan Wu

AbstractRecent studies suggested that at least some of the observed SNe Ia originate from the double-degenerate model, which involves the merging of double carbon-oxygen white dwarfs (CO WDs). However, the delay time distributions predicted by previous theoretical studies are inconsistent with the observed SNe Ia at the early epoches of < 1 Gyr and old epoches of > 8 Gyr. Previous studies suggested that the CO WD+He subgiant channel has a significant contribution to the formation of massive double CO WDs, the merging ofwhich may produce SNe Ia. In the presentwork, we added this channel into the double-degenerate model to investigate its influence on the delay time distributions of SNe Ia. We found that the delay time distributions would match better with the observed SNe Ia when the CO WD+He subgiant channel is included in the double-degenerate model.


2010 ◽  
Vol 10 (9) ◽  
pp. 927-934 ◽  
Author(s):  
Xiang-Cun Meng ◽  
Wu-Ming Yang ◽  
Zhong-Mu Li

2015 ◽  
Vol 580 ◽  
pp. A118 ◽  
Author(s):  
Kai S. Marquardt ◽  
Stuart A. Sim ◽  
Ashley J. Ruiter ◽  
Ivo R. Seitenzahl ◽  
Sebastian T. Ohlmann ◽  
...  

2002 ◽  
Vol 187 ◽  
pp. 103-108
Author(s):  
X.-D. Li ◽  
E. P. J. van den Heuvel

Supersoft X-ray sources (hereafter SSS) are a class of luminous (bolometric luminosity ~ 1037 − 1038 erg s−1) objects with a characteristic radiation temperature of 30 to 60 eV (Hasinger 1994; Kahabka & Trümper 1996). The most popular model for SSS is that they are massive white dwarfs steadily burning nuclear fuel accreted from a more massive binary companion at a rate near or above the Eddington limit (van den Heuvel et al. 1992).


2019 ◽  
Vol 15 (S357) ◽  
pp. 79-83
Author(s):  
Surajit Kalita ◽  
Banibrata Mukhopadhyay

AbstractRecent evidence of super-Chandrasekhar white dwarfs (WDs), from the observations of over-luminous type Ia supernovae (SNeIa), has been a great astrophysical discovery. However, no such massive WDs have so far been observed directly as their luminosities are generally quite low. Hence it immediately raises the question of whether there is any possibility of detecting them directly. The search for super-Chandrasekhar WDs is very important as SNeIa are used as standard candles in cosmology. In this article, we show that continuous gravitational wave can allow us to detect such super-Chandrasekhar WDs directly.


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