Planets do not take much longer to form after stars have formed. For example, the Sun formed 4.6 billion years ago and the Earth about 4.5 billion years ago. However, scientists now say it is not necessarily the only possibility. They say planets can form even if a star is nearing its death, long after the star was formed. Dying stars leading to the formation of planets is a completely new theory. If confirmed, this finding can change how we understand the functions of the universe and planetary evolution.

In our solar system, Earth and other planets did not take much time to form after the Sun originated first. Within a million years of the Sun’s birth, matter around it clumped into a protoplanetary disc. This disc, a gigantic pancake made of dust and gas with the Sun in the middle, is where planets were formed. But new stars, like the Sun in this case, aren’t the only stars with a disc of raw material rotating around them. Some old, dying stars, too, have these discs. For example, around binary stars — two stars that orbit each other — one of which is dying.

A study titled,“A population of transition disks around evolved stars: Fingerprints of planets”, published in the journal Astronomy & Astrophysics, says the second star’s gravitational pull may lead the expelled material from the dying star to form a new revolving disc. But that’s already known. What’s new is the possibility that a second generation of planets can form in the disc. The study says this is how planets are forming in one in 10 of these binary stars.

The study’s first author and KU Leuven astronomer Jacques Kluska said that they found a big cavity in the disc in 10 percent of the evolved binary stars with discs that they analysed. Kluska added that this indicated that something was floating nearby and had collected all the matter in the cavity’s vicinity.

This object most certainly could be a planet but astronomers aren’t sure yet. More research is likely to unfold the mystery.