Although the main sequence of a star such as the Sun does not end in a supernova, it can still be a significant part of the stars’ lives. It won’t be an easy task..
The star becomes unstable when it runs out of fuel, and puffs up to an incredible size before exploding. It then loses its outer material, while its core collapses into a void. Small, extremely dense white dwarf.
The giant, puffy red stage that is the Sun could reach as far as MarsA process that could destabilize or destroy nearby planets.
We have seen White dwarf stars with planetsThey are able to survive (or even form after) the process. Scientists are increasingly finding that exoplanets are being eaten by white dwarfs.
This is possible because of the ‘pollution’ by planetary elements within the atmospheres white dwarf stars. The study of this phenomenon is called Neroplanetology.
Astronomers now have the oldest example of this phenomenon: A white dwarf formed 10.2 billion year ago and devoured an exoplanet.
The white dwarf, located around 90 light years from Earth, is extremely small and dim with a unique hue that is redder than any other white dwarf stars. Unusually blue, a second white dwarf star was formed 9 billion years ago. The team discovered that both stars are currently polluted by planetary debris.
While the red star, WD J2147-4035 represents the oldest known polluted white dwarf, the blue star, WD J1922+0233 is more intriguing: The elements found within its atmosphere indicate that the star is likely to be eating a similar-sized planet to Earth.
“We are finding the oldest stellar remains in the Milky Way that have been polluted by once Earthlike planets.” Abbigail Elves, astrophysicistUniversity of Warwick, UK. “It is amazing to consider that this occurred on the scale 10 billion years ago and that those planets died well before the Earth was created.”
From the star’s light, we can decode the chemical composition of the star’s atmosphere. All wavelengths are not equal: some are stronger and some are weaker. This is because elements have the ability to absorb and re-emit sunlight, changing the spectrum of light coming from the star.
Scientists are becoming better at identifying the absorption and emission characteristics on spectrums that are associated with particular elements.
Elms and her coworkers conducted a variety of studies on the white dwarfs discovered by the European Space Agency’s Gaia satellite observatory.
White dwarf stars do not have the ability to fuse elements in their cores and their temperatures are decreasing at a known rate. Researchers used the temperatures of the stars to measure how long it has been since they formed after the death of a Sun-like Star.
Then, they analysed the spectra of the stars to determine their atmospheric compositions. The red star contained sodium, lithium and potassium. They also found carbon. They found potassium, calcium, and sodium on the blue star.
White dwarfs are so strong in gravitational gravity that heavy elements such as these should disappear quickly into their interior. This suggests that material causing these elements is still falling onto stars from the debris clouds surrounding them.
The team found that the pollution in WD J2147-4035 was most likely remnants from a planetary system which had orbited star before it died. They also discovered that star is slowly falling into it over billions years.
It is the oldest known planetary system in our Milky Way. However, it is currently disintegrating and vanishing.
The debris polluting the WD J1922+0233 has an identical composition to Earth’s continent crust. This suggests that the planet may be Earth-like and orbit a Sun-like star, which lived and died billions years before the formation of the Solar System.
It is like a fossil record of a galaxy that can tell us how the planetary systems in our Milky Way looked in the past before we came to admire its wonders.
“When these older stars formed over 10 million years ago, it was less metal-rich than now because metals are formed by evolved stars and huge stellar explosions.” says astrophysicist Pier-Emmanuel TremblayUniversity of Warwick
“The observations of two white dwarfs offer a window into the formation and evolution of planets in a different environment than the Solar System’s.
The results of the research were published in Monthly Notices of The Royal Astronomical Society.
