Astronomers have discovered where planets primarily form in the Milky Way.

Astronomers have already discovered over 6000 exoplanets, and the search continues. The authors of a new study published on the arXiv preprint server have determined where planets predominantly form in our Milky Way galaxy. They found that stars with massive planets tend to have higher metallicity compared to those with fewer metals. Additionally, they discovered that stars with planets are generally younger than those without, as noted by Universe Today.

One of the key factors in planet formation within our galaxy is the presence of metals, which are elements heavier than hydrogen and helium, a property known as metallicity. It’s worth mentioning that astronomers refer to all chemical elements other than hydrogen and helium as metals, although this is not entirely accurate from a chemical standpoint.

Heavy chemical elements are formed in the cores of stars and during supernova explosions. This process disperses metals throughout space, contributing to the interstellar medium. Understanding the distribution of metals provides insights into the age, history, and rate of star and planet formation.

Astronomers studied what is known as the galactic birth radius. This term refers to the distance from the center of the galaxy where stars—and consequently planets—are formed. Using existing astronomical data, scientists were able to estimate the ages of two groups of stars: those with planets and those without. This allowed them to calculate the galactic birth radius for planets based on the initial positions of the stars, their ages, and their metallic content.

The results indicated that stars with planets have a higher iron-to-hydrogen ratio, are younger, and were born closer to the center of our galaxy compared to those without planets.

Researchers also found that stars with massive planets exhibit a different distribution of iron-to-hydrogen ratios and ages than stars with at least one small-mass planet, as well as those with only small-mass planets.

The study suggests that Earth-like planets typically form around stars with a higher iron-to-hydrogen ratio.

Thus, scientists concluded that larger planetary systems resembling our own are most commonly formed closer to the center of our galaxy. This region contains a higher concentration of metals, and while planetary systems can migrate to the outer parts of the Milky Way, this discovery provides a promising direction for the search for new worlds beyond our Solar System.