IISc study says strong magnetic fields could allow white dwarfs to grow beyond the Chandrasekhar limit

When a dying star runs out of fuel and sheds its outer layers, its remaining core can become an approximately Earth-sized, extremely dense stellar remnant called a ‘white dwarf’. | Photo Credit: K. MURALI KUMAR

Simulations by researchers of Indian Institute of Science (IISc) and their collaborators show that strong internal magnetic fields could allow some white dwarfs to grow to substantially higher masses than determined by the Chandrasekhar limit.

When a dying star runs out of fuel and sheds its outer layers, its remaining core can become an approximately Earth-sized, extremely dense stellar remnant called a “white dwarf”. For a white dwarf that is not strongly rotating or magnetised, there is a well-known upper mass limit of about 1.4 times the mass of the Sun, known as the “Chandrasekhar limit”.

In one of their simulations, the researchers found that a magnetised carbon-oxygen white dwarf can reach about 2.4 times the mass of the Sun – well above the limit.