Zobrazeno 1 - 10
of 38
pro vyhledávání: '"Stellar convective zones"'
Publikováno v:
The Astrophysical Journal Letters, Vol 964, Iss 1, p L15 (2024)
The origin of large magnetic fields (≳10 ^6 G) in isolated white dwarfs is not clear. One possible explanation is that crystallization of the star’s core drives compositional convection, which when combined with the star’s rotation, can drive a
Externí odkaz:
https://doaj.org/article/cf5302650f404edc94df493a6a01ac87
Autor:
Huaqing Mao, Paul Woodward, Falk Herwig, Pavel A. Denissenkov, Simon Blouin, William Thompson, Benjamin McDermott
Publikováno v:
The Astrophysical Journal, Vol 975, Iss 2, p 271 (2024)
We present 3D hydrodynamical simulations of core convection with a stably stratified envelope of a 25 M _⊙ star in the early phase of the main sequence. We use the explicit gas-dynamics code PPMstar , which tracks two fluids and includes radiation
Externí odkaz:
https://doaj.org/article/d22e34a710974405bc41fda3a0352fd8
Publikováno v:
The Astrophysical Journal, Vol 975, Iss 1, p 63 (2024)
We investigate the evolution of magnetic fields generated by the crystallization-driven dynamo in carbon–oxygen white dwarfs (WDs) with masses ≲1.05 M _⊙ . We use scalings for the dynamo to demonstrate that the initial magnetic field strength (
Externí odkaz:
https://doaj.org/article/bd9c22763c7548c7bcdee126c6b5b4c8
Publikováno v:
The Astrophysical Journal, Vol 974, Iss 2, p 194 (2024)
We adopt a set of second-order differential equations ( k − ω model) to handle core convective overshooting in massive stars, simulate the evolution of nitrogen sequence Wolf–Rayet (WNL) stars with different metallicities and initial masses, bot
Externí odkaz:
https://doaj.org/article/7cd50eb6140e40cba47ffd39a4ccc29d
Autor:
Alexa C. Beyer, Russel J. White
Publikováno v:
The Astrophysical Journal, Vol 973, Iss 1, p 28 (2024)
Main-sequence stars transition at mid-F spectral types from slowly rotating (cooler stars) to rapidly rotating (hotter stars), a transition known as the Kraft Break and attributed to the disappearance of the outer convective envelope, causing magneti
Externí odkaz:
https://doaj.org/article/3fa57ace41c042d397a2d640eb8e784d
Publikováno v:
The Astrophysical Journal, Vol 969, Iss 1, p 10 (2024)
We investigate crystallization-driven convection in carbon–oxygen white dwarfs. We present a version of the mixing length theory that self-consistently includes the effects of thermal diffusion and composition gradients, and provides solutions for
Externí odkaz:
https://doaj.org/article/081d12ebe0634dadb26dfe2f925056ce
Publikováno v:
The Astrophysical Journal, Vol 965, Iss 2, p 171 (2024)
Some physical processes that occur during a star's main-sequence evolution also affect its post-main-sequence evolution. It is well known that stars with masses above approximately 1.1 M _⊙ have well-mixed convective cores on the main sequence; how
Externí odkaz:
https://doaj.org/article/85f54c782d44407d9be7679b7da72424
Autor:
Cole Johnston, Mathias Michielsen, Evan H. Anders, Mathieu Renzo, Matteo Cantiello, P. Marchant, Jared A. Goldberg, Richard H. D. Townsend, Gautham Sabhahit, Adam S. Jermyn
Publikováno v:
The Astrophysical Journal, Vol 964, Iss 2, p 170 (2024)
One-dimensional stellar evolution calculations produce uncertain predictions for quantities like the age, core mass, core compactness, and nucleosynthetic yields; a key source of uncertainty is the modeling of interfaces between regions that are conv
Externí odkaz:
https://doaj.org/article/ce66b8e98b7a468c94b2a6bde2678dd3
Autor:
Francesco Addari, Paola Marigo, Alessandro Bressan, Guglielmo Costa, Kendall Shepherd, Guglielmo Volpato
Publikováno v:
The Astrophysical Journal, Vol 964, Iss 1, p 51 (2024)
The initial–final mass relation (IFMR) plays a crucial role in understanding stellar structure and evolution by linking a star’s initial mass to the mass of the resulting white dwarf. This study explores the IFMR in the initial mass range 0.8 ≤
Externí odkaz:
https://doaj.org/article/da4a6222741c4f4c8d7401fe460e3af2
Autor:
M. H. Montgomery, Bart H. Dunlap
Publikováno v:
The Astrophysical Journal, Vol 961, Iss 2, p 197 (2024)
Accurate models of cooling white dwarfs must treat the energy released as their cores crystallize. This phase transition slows the cooling by releasing latent heat and also gravitational energy, which results from phase separation: liquid C is releas
Externí odkaz:
https://doaj.org/article/fe23198c7d1f4faa9ccca237c905dbc7