Astronomers continue to hunt for the elusive kind of star known as Population III stars, the first stars to appear in the young universe. New research has revealed that the James Webb Space Telescope may be on the cusp of discovering them.
The stars that exist in the universe today are nothing like the first generation of stars to appear in the cosmos. With every generation of stars that lives and dies, more metals, which in astronomy are any element heavier than hydrogen and helium, add to the mix. The presence of these metals fundamentally changes the characteristics of the next generation of stars.
In contrast, the first generation of stars formed from an almost pristine mixture of pure hydrogen and helium using mechanisms that we do not yet fully understand. Members of the first generation of stars to appear in that primordial soup are known as Population III (or Pop III) stars, while intermediate stars are called Pop II stars, and then the latest generation of stars are called Pop I. Astronomers have searched for decades for any remnant populations of Pop III stars in the modern-day universe to no avail.
That means that they have to go back to earlier times to catch a glimpse of a Pop III star. But observations of the early epochs of the history of the universe are extremely difficult, and it’s unclear if our searches will be successful. Recently a team of astrophysicists conducted computer simulations of the formation of the first stars in the universe. They specifically looked to see if how long Pop III stars could continue forming in the young universe.
They found that Pop III stars could still appear in relatively mature galaxies. The galaxies had to have reservoirs of pure hydrogen and helium still remaining. If the conditions were just right, Pop III stars could still form in those pockets. Even though those stars wouldn’t technically be amongst the first generation of stars to appear in the universe, they would still have many of the same properties.
The astronomers also discovered in their simulations that Pop III stars could appear on the outskirts of very massive galaxies where pure hydrogen and helium would continue to accrete onto the galaxy, and away from the polluting impacts of stars deeper in the interior of the galaxy. The simulation suggest that Pop III stars could remain inside of galaxies right to the uppermost edge of the deepest capabilities of the James Webb Space Telescope
This suggests that the JWST could be capable of directly observing Pop III stars in distant galaxies. The hunt is on.