This is the biggest nova super-remnant ever discovered
What's the story
A team of astronomers has discovered a rare nova super-remnant (NSR) around the recurrent nova LMCN 1971-08a in the Large Magellanic Cloud (LMC). This is the first time an NSR has been detected in the LMC. The discovery was made by analyzing data from several astronomical surveys and MeerKAT radio telescope observations. The findings were published on the arXiv preprint server.
NSR explained
What are nova super-remnants?
NSRs are huge shell-like structures that are much larger than individual eruption nova shells. They form when repeated nova eruptions push the surrounding material away from a nova into a dense outer shell. Despite being predicted to form around all novae, only four such structures have been found so far, three of them in our galaxy.
Nova profile
Characteristics of LMCN 1971-08a
LMCN 1971-08a, one of the four known recurrent novae in the LMC, has a recurrence period of about 38 years. Its last eruption was observed in 2009. The nova is a fast-declining one consisting of a white dwarf with a mass between 1.1 and 1.3 solar masses, which accretes material from its sub-giant companion star. The probable orbital period of this system is estimated to be around 1.2 days.
Discovery
An NSR was detected around LMCN 1971-08a
The team led by Michael W. Healy-Kalesh from Germany's Friedrich-Alexander University, discovered a coherent, shell-like structure spatially coincident with LMCN 1971-08a. The structure has a circular shape and is brighter to the northeast and southwest, with a fainter boundary connecting these two parts to the northwest. The data collected suggests that this newly discovered structure is an NSR with a diameter of about 650 light years.
Structure details
Largest nova super-remnant discovered so far
The outer shell of the NSR around LMCN 1971-08a is estimated to have a mass of about 4,130 solar masses and an expansion velocity of some 20km/s. The age of this NSR is estimated to be around 2.4 million years. The size of this nova super-remnant makes it the largest one ever discovered so far.