Einstrahlzahl φ ij (view factor F ij )

We study explosion characteristics of ultra-stripped supernovae (SNe), which are candidates of SNe generating binary neutron stars (NSs). As a first step, we perform stellar evolutionary simulations of bare carbon-oxygen cores of mass from 1.45 to 2.0 M ⊙ until the iron cores become unstable and start collapsing. We then perform axisymmetric hydrodynamics simulations with spectral neutrino transport using these stellar evolution outcomes as initial conditions. All models exhibit successful explosions driven by neutrino heating. The diagnostic explosion energy, ejecta mass, Ni mass, and NS mass are typically ∼ 10 50 erg, ∼ 0.1M ⊙ , ∼ 0.01M ⊙ , and ≈ 1.3M ⊙ , which are compatible with observations of rapidly-evolving and luminous transient such as SN 2005ek. We also find that the ultra-stripped SN is a candidate for producing the secondary low-mass NS in the observed compact binary NSs like PSR J0737-3039.

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“…The diffusion coefficient is adopted from Eq. (2) in Herwig (2000) and the parameter on the scale height f is set to be 0.01.…”

Section: Stellar Evolution and Progenitor Structuresmentioning

confidence: 99%

Neutrino-driven explosions of ultra-stripped Type Ic supernovae generating binary neutron stars

Suwa

Yoshida

Shibata

et al. 2015

Mon. Not. R. Astron. Soc.

104

116

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“…More recently, Herwig (2000) and Cristallo et al (2009) successfully employed convective overshoot to reproduce the mixing mechanism responsible for the PMZ. Herwig (2000) modelled the overshoot via the diffusion coefficient while Cristallo et al (2009) via the convective velocity, both using an exponential decay function of the form:…”

Section: Current Models For the Formation Of 13 C Pocketsmentioning

confidence: 99%

Partial mixing and the formation of 13C pockets in AGB stars: effects on the s-process elements

Buntain

Doherty

Lugaro

et al. 2017

Monthly Notices of the Royal Astronomical Society

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The production of the elements heavier than iron via slow neutron captures (the s process) is a main feature of the contribution of asymptotic giant branch (AGB) stars of low mass (< 5 Msun) to the chemistry of the cosmos. However, our understanding of the main neutron source, the 13 C(α,n) 16 O reaction, is still incomplete. It is commonly assumed that in AGB stars mixing beyond convective borders drives the formation of 13 C pockets. However, there is no agreement on the nature of such mixing and free parameters are present. By means of a parametric model we investigate the impact of different mixing functions on the final s-process abundances in low-mass AGB models. Typically, changing the shape of the mixing function or the mass extent of the region affected by the mixing produce the same results. Variations in the relative abundance distribution of the three s-process peaks (Sr, Ba, and Pb) are generally within +/-0.2 dex, similar to the observational error bars. We conclude that other stellar uncertainties -the effect of rotation and of overshoot into the C-O core -play a more important role than the details of the mixing function. The exception is at low metallicity, where the Pb abundance is significantly affected. In relation to the composition observed in stardust SiC grains from AGB stars, the models are relatively close to the data only when assuming the most extreme variation in the mixing profile.

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“…CG68: Cox & Giuli (1968); BV58: Böhm-Vitense (1958); CGM96: Canuto et al (1996); H65: Henyey et al (1965). M75: Maeder (1975); H00: Herwig (2000). GN93: Grevesse & Noels (1993); GS98: Grevesse & Sauval (1998).…”

Section: Stellar Model Comparisonsmentioning

confidence: 99%

A seismic and gravitationally bound double star observed byKepler

Appourchaux

Antia

Ball

et al. 2015

A&A

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Context. Solar-like oscillations have been observed by Kepler and CoRoT in many solar-type stars, thereby providing a way to probe stars using asteroseismology. Aims. The derivation of stellar parameters has usually been done with single stars. The aim of the paper is to derive the stellar parameters of a double-star system (HIP 93511), for which an interferometric orbit has been observed along with asteroseismic measurements. Methods. We used a time series of nearly two years of data for the double star to detect the two oscillation-mode envelopes that appear in the power spectrum. Using a new scaling relation based on luminosity, we derived the radius and mass of each star. We derived the age of each star using two proxies: one based upon the large frequency separation and a new one based upon the small frequency separation. Using stellar modelling, the mode frequencies allowed us to derive the radius, the mass, and the age of each component. In addition, speckle interferometry performed since 2006 has enabled us to recover the orbit of the system and the total mass of the system. Results. From the determination of the orbit, the total mass of the system is 2.34 +0.45 −0.33 M . The total seismic mass using scaling relations is 2.47 ± 0.07 M . The seismic age derived using the new proxy based upon the small frequency separation is 3.5 ± 0.3 Gyr. Based on stellar modelling, the mean common age of the system is 2.7-3.9 Gyr. The mean total seismic mass of the system is 2.34-2.53 M consistent with what we determined independently with the orbit. The stellar models provide the mean radius, mass, and age of the stars as R A = 1.82−1.87 R , M A = 1.25−1.39 M , Age A = 2.6-3.5 Gyr; R B = 1.22−1.25 R , M B = 1.08−1.14 M , Age B = 3.35-4.21 Gyr. The models provide two sets of values for Star A: [1.25-1.27] M and [1.34-1.39] M . We detect a convective core in Star A, while Star B does not have any. For the metallicity of the binary system of Z ≈ 0.02, we set the limit between stars having a convective core in the range [1.14-1.25] M .

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Einstrahlzahl φ ij (view factor F ij )

Cited by 407 publications

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Neutrino-driven explosions of ultra-stripped Type Ic supernovae generating binary neutron stars

Neutrino-driven explosions of ultra-stripped Type Ic supernovae generating binary neutron stars

Partial mixing and the formation of 13C pockets in AGB stars: effects on the s-process elements

A seismic and gravitationally bound double star observed byKepler

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