Telescope confirms new evidence of white dwarf cannibalising its companion star

Work by researchers operating the Southern African Large Telescope (SALT) in the Northern Cape has confirmed that a white dwarf star is cannibalising its companion star.

The find has led astronomers to change their view on how massive radiation bursts occur on white dwarf stars.

The star, ASASSN-16oh, some 200 000 light years from Earth, was initially discovered on December 2 2016, but additional observation from SALT and other instruments was required to confirm the find.

Observations of the star showed that it was a “supersoft” X-ray source, produced by gas at temperatures of about 900 000°C.

Such supersoft sources are associated with a runaway thermonuclear explosion on the surface of the white dwarf. They usually occur over a relatively short period of time.


“The discovery has shown that there is more than one way for a white dwarf to emit this radiation, nuclear fusion, but now also accretion on to a white dwarf,” science engagement officer at the South African Astronomical Observatory Dr Daniel Cunnama told the media.

Astronomers had to act quickly to capture the radiation from the white dwarf.

“We were fortunate to be able to react quickly to its discovery and undertake crucial observations during the outburst phase,” said Dr David Buckley, the principal investigator of the SALT Large Science Programme on transients.

But the data shows that ASASSN-16oh is not a normal supersoft source.

The star is taking material from its red giant companion, which is swirling around it in what astronomers call an accretion disk.

The gas from the red giant spirals around the white dwarf and when it falls onto the star, it emits a burst of radiation.

“The transfer of mass is happening at a higher rate than in any system we’ve caught in the past,” said Professor Tom Maccarone, lead author of the ASASSN-16oh discovery paper that appeared in the December 3 issue of Nature Astronomy.

The radiation is an indicator that ASASSN-16oh may end up as a supernova as it consumes more of the red giant’s material.

And it won’t end happily for any planets that may have been in orbit around the system.

“Any planets in the system would either have been destroyed as the two stars began spiralling toward each other or flung out far from the system,” said Cunnama. — News24

Subscribe to the M&G

These are unprecedented times, and the role of media to tell and record the story of South Africa as it develops is more important than ever.

The Mail & Guardian is a proud news publisher with roots stretching back 35 years, and we’ve survived right from day one thanks to the support of readers who value fiercely independent journalism that is beholden to no-one. To help us continue for another 35 future years with the same proud values, please consider taking out a subscription.

Duncan Alfreds
Duncan Alfreds
Content Producer, News24 and Tech News Writer, Fin24.com

Related stories

Advertising

Subscribers only

Vodacom swindled out of more than R24m worth of Apple...

A former employee allegedly ran an intricate scam to steal 8700 phones from the cellular giant

Come what may, the UIF will pay

The fund – the main safety net for unemployed workers – will run at an almost R20-billion deficit

More top stories

We will find resources to ensure the Zondo commission completes...

Justice Minister Ronald Lamola says his department will ensure the state capture commission is afforded the financial resources to complete its work, despite the treasury’s uncertainty

Covid-19 variant may protect people against reinfection and other variants,...

The 501Y.V2 strain produces strong antibodies, but it’s not known how long immunity lasts, so being vaccinated remains essential

Tobacco industry calls Dlamini-Zuma’s bid to appeal ban a...

The minister could spend the state’s money on fighting Covid-19 and cigarette cartels, tobacco manufacturers argue

Zondo commission: Glencore sold Optimum to portray me as a...

Former Eskom chief executive paints himself as the victim of a plot at the hands of President Cyril Ramaphosa’s former business associates
Advertising

press releases

Loading latest Press Releases…