A recent scientific study of white dwarfs has revealed that the dead stars, which are smaller and burn less intensely than main sequence ones, were actually the center of gravity for a number of solar systems. The way researchers figured that out was by measuring the amount of pollutants in the dead stars, by using the infrared Spitzer Space Telescope. It was able to detect the faint trail left behind by the cosmic dust that entered a number of white dwarfs, and to ascertain that between one and three percent of all these stars had, at one point, a solar system around them.

White dwarfs are usually formed from middleweight stars, similar in size and mass to our own Sun. When they reach the end of their life cycle, they swell up into what is known as a red giant, which then begins to shed its atmosphere. Eventually, after this process is complete, the new star will considerably decrease its dimensions and also lose hydrogen as its main source of power. All that will remain in the formation will be a small amount of hydrogen, helium, as well as other heavy elements.

By analyzing the ratio of these elements in the entire star, and by observing the traits of the cosmic dust that has also been brought in, experts can now determine if the white dwarf they are studying may or may not have sustained a fully functional solar system in the past. Recent investigations revealed that asteroids or large meteorites could be the main reason why white dwarfs were “polluted” with heavy elements. Debris from these bodies fall into the star and create the chemical “abnormality,” which can now be used to detect which of the stars is most likely to have housed a solar system.

“In the quest for Earth-like planets, we have now identified numerous systems which are excellent candidates to harbor them. Where they persist as white dwarfs, any terrestrial planets will not be habitable, but may have been sites where life developed during a previous epoch. With high quality optical and ultraviolet observations, we should be able to measure up to two dozen different elements in debris-polluted white dwarfs. We can then address the question, 'Are there rocky extrasolar planets we find similar to the terrestrial planets of our own solar system?'” University of Leicester expert Jay Farihi, who was also a member of the team that made the recent discovery, explained, as quoted by Space.