Astronomers See Star Being 'Reborn'

The process of stellar evolution takes millions of years, and human life is absolutely just a speck in this astronomic time. Seeing this process unfold is extremely once in a lifetime chance. However, as per a recent study, a team of researchers have reportedly witnessed the phenomena.

The team of astronomers who have been observing the star SAO 244567 over the last 20 years have said it is undergoing a dramatic resurrection. In a study published in the Monthly Notices of the Royal Astronomical Society, the team led by Nicole Reindl from the University of Leicester in the U.K. said they have witnessed star evolving "real-time," using data from the Hubble Space Telescope

SAO 244567 is in the center of the Stingray Nebula, some 2,700 light-years from Earth. Observations of the star over the last 45 years have shown it evolving. The team noted that during the initial period between 1971 and 2002, the star had a surface temperature of nearly 40,000 degrees Celsius. However, a recent observation has showed the star to be cooling down and expanding.

Hubble News explained that the evolution of low-mass stars happens very slowly, and that event in SAO 244567 was unusual as observation data suggested its original mass must be similar to that of the Sun. It said had SAO 244567's initial mass been 3 to 4 times larger, the phenomena would have been possible.

The team said the rapid heating in SAO 244567 may have been caused by sudden ignition of helium, just outside its core. Reindl called the event as a helium-shell flash, explaining that it "forces the already very compact star to expand back to giant dimensions - the born-again scenario."

The heating and cooling phenomena have been observed in other stars, but SAO 244567 is the first observed to display both, challenging previous models of evolution of central stars in planetary nebulae. "We need refined calculations to explain some still mysterious details in the behavior of SAO 244567," Reindl said, adding that a further study would provide new information into stellar evolution.