Contemporary theories contemplate that in about 5 billion years, the Sun will cease to exist in its known appearance and become a white dwarf, demolishing everything around it.
However, the recent discovery of astrophysicists leaves a dash of hope for humanity.
Astronomers discovered a gas planet the size of Jupiter in the orbit of a white dwarf. This discovery shows that white dwarfs or dead stars can be centers of a planetary system, which was previously considered impossible.
In their studies, scientists used data from NASA’s TESS space telescope in 2018 to search for exoplanets, i.e. planets that do not belong to our solar system. The results were published on September 16 in the journal Nature.
The truth is that 97% of the stars we know are or will be white dwarfs. It’s a form of star evolution.
Being a huge nuclear reactor, where different types of nuclear fusion occur throughout its life, the star burns its fuel. And when it is finished, one of the options is to become a white dwarf or a red dwarf, depending on its initial mass.
“When a white dwarf is born, it destroys all nearby planets, and generally its enormous gravity destroys anything that gets too close to it,” explains Andrew Vanderburg, assistant professor of astronomy at the University of Wisconsin-Madison in a statement from NASA press.
The newly found space body, which was named WD 1856 b, will help to understand whether it is possible to preserve life on a planet after its star collapses and becomes a white dwarf, say researchers at Cornell University.
“If rocky planets exist around white dwarfs, we could spot signs of life on them in the next few years,” said Lisa Kaltenegger, associate professor of astronomy at Cornell University and director of the Carl Sagan Institute.
According to the astronomer, exoplanets subject to white dwarfs are likely to harbor life, but detecting it requires more precise instruments, such as the James Webb space observatory. It is a joint project of NASA, the European Space Agency and the Canadian Space Agency to replace the famous Hubble in Earth orbit, its launch is planned in 2021.
“Observing planets similar to Earth orbiting white dwarfs, the James Webb Space Telescope can detect water and carbon dioxide within hours,” said co-author, Ryan J. MacDonald, which was published do in The Astrophysical Journal Letters.
“Two days of observing time with this powerful telescope would allow the discovery of biosignature gases, such as ozone and methane,” says the researcher.
The WD 1856 b is not the best place to find life, at least in the way we know it. It is a gas giant where an atmosphere similar to the one on Earth cannot exist. However, it may be found on other, smaller, rockier planets in the orbits of other white dwarfs.
“What if the death of the star is not the end for life? Could life go on, even once our sun has died? Signs of life on planets orbiting white dwarfs would not only show the incredible tenacity of life, but perhaps also a glimpse into our future,” concludes Kaltenegger.