On the stability of ultra-magnetized white dwarfs

Instability Due to Electron Captures of Nuclei 56Ni, 56Co, 56Fe, 56Mn, 56Cr, and 56V in Strongly Magnetized Super-Chandrasekhar White Dwarfs

“…Depending on the composition of the SMSWD, Cáceres et al (2014) have discussed in detail the stability of Ultra-magnetized White Dwarfs with interior fields upto ∼10 18 G. They derived different threshold energies for the triggering of EC at the corresponding maximum magnetic field B max and central density ρ c . For the triggering of an EC, the magnetic field is B ≈ 1.16 × 10 15 G at a corresponding center density ρ c 5.7 × 10 8 g cm −3 for iron group nuclei in SMSWD.…”

“…When the electron Fermi energy is more than the threshold energy, the EC will be quickly triggered. The EC, due to energetic electrons, consumes a large number of electrons, reduces the electron abundance, and ultimately leads to the instability of gravitational collapse in SMSWD (Cáceres et al 2014). Recently, some authors have discussed the EC instability in magnetic white dwarfs in detail (e.g., Chamel et al 2013;Cáceres et al 2014;Chamel & Fantina 2015).…”

“…The EC, due to energetic electrons, consumes a large number of electrons, reduces the electron abundance, and ultimately leads to the instability of gravitational collapse in SMSWD (Cáceres et al 2014). Recently, some authors have discussed the EC instability in magnetic white dwarfs in detail (e.g., Chamel et al 2013;Cáceres et al 2014;Chamel & Fantina 2015). Following the works of Chamel & Fantina (2015), we also discuss the threshold mass density (TMD) and threshold pressure (TP) of EC in SMSWD, taking into account electronion interactions and nuclear binding energy.…”

“…However, these studies only focus on the condition of neutron stars and have overlooked the effect of SMFs on the instability of an SMSWD. Some authors have studied the EC instability in magnetic white dwarfs (e..g., Chamel et al 2013;Cáceres et al 2014;Chamel & Fantina 2015). They show that the EC and pycnonuclear reactions in SMSWDs may severely limit their stability.…”

Electron Captures and Stability of White Dwarfs

“…24 within the theory of polytropes making use of the fact that P ∝ ρ 2 in the strongly quantizing regime. However, it was soon realized that this assumption is unrealistic and that the influence of the magnetic field itself on the stellar structure cannot be ignored 27,34,[66][67][68] . Moreover, the magnetic-field config- uration inside the star should be calculated from Maxwell's equations consistently with the stellar equilibrium equations.…”