9 January 2019
Astrophysicists have discovered an enormous bubble currently being ‘blown’ by the regular eruptions from a star in a nearby galaxy – and studying this phenomenon could help scientists to better understand how the universe expands.
M31N 2008-12a Super Remnant. Image from Liverpool Telescope (left) and Hubble Space Telescope (right).
(Credit: Matt Darnley/LJMU)
An international team of researchers, led by Liverpool John Moores University (LJMU), have been studying an enormous shell-like nebula – a cloud of gas and space dust – in our neighbouring Andromeda Galaxy. The shell, called a ‘nova remnant’, surrounds two stars – one of which is constantly erupting.
The explosions which are causing the shell to expand are happening on the surface of a white dwarf. Every year, the white dwarf undergoes a thermonuclear explosion much like a hydrogen bomb, shooting out energy and mass in all directions.
This acts like a snow plough, causing all the space dust to pile up to form the shell or bubble, or ‘super-remnant’.
At almost 400 lightyears across and still growing, this is far bigger than a typical nova remnant (usually around a lightyear in size), suggesting that this vast shell is in fact the remains of not just one eruption but possibly millions all from the same system.
Dr Matt Darnley, of LJMU’s Astrophysics Research Institute and who was supported by STFC, explains: “Studying this star system and its super-remnant could help us to understand how some white dwarfs grow to their critical upper mass and how they actually explode once they get there, which helps us to work out how the universe expands and grows.”
More information is available on the LJMU website.
Last updated: 15 January 2019