February 25, 2021

This is how our sun will die

Astronomers have witnessed, for the first time, a rare dynamic event that foreshadows the death of a giant red star, a finding that reinforces the predictions about the final outcome of our Sun, reports Ep.

Meridith Joyce, an astronomer at the National University of Australia (ANU), co-directed the study focusing on the T star Ursae Minoris (T UMi), which was similar to the sun.

"This has been one of the rare opportunities in which the signs of aging can be seen directly in a star on human timescales," Joyce said.

"We anticipate that our Sun and UMi they will end their lives much more quietly and slowly compared to a supernova, a bright and powerful explosion. "

The findings support the prediction that our Sun will become a red giant and then a ring-shaped gas shell that will expand and shine in five billion years, leaving a small white dwarf as a remnant, said Dr. Joyce

"It will get much bigger as you approach death (Venus, Mercury and possibly Earth will be eaten in the process) before shrinking to become a white dwarf, "he said in a statement.

T UMi was born about 1.2 billion years ago, with a mass approximately twice that of our Sun, in the constellation of Ursa Minor, more than 3,000 light years from Earth.

The team discovered that during the last million years, during its last stage of life before its last transition to a white dwarf, T UMi has been experiencing a series of pulses, in which its size, brightness and temperature have fluctuated greatly .

"The energy production in UMi T has become unstable. During this phase, nuclear fusion explodes deep inside, causing 'hiccups' we call thermal pulses.

"These pulses cause drastic and rapid changes in the size and brightness of the star, which can be detected for centuriess. The pulses of ancient stars like T UMi also enrich the entire Universe with elements that include carbon, nitrogen, tin and lead. "

The team has observed that the star has decreased in size, brightness and temperature in the last 30 years. "We believe that the star is entering one of its last remaining pulses, and we hope to see it expand again in our lives. The star will eventually become a white dwarf in a few hundred thousand years. "said Joyce.

"Both amateur and professional astronomers will continue to observe the evolution of the star over the next decades, which will provide a direct test of our predictions within the next 30 to 50 years."

The study is published in The Astrophysical Journal.

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