UT Professor Looks at What Types of Stars Form Rocky, Earth-Size Planets

As astronomers continue to find more and more planets around stars beyond our own sun, they are trying to discover patterns and features that indicate what types of planets are likely to form around different kinds of stars. This will hopefully inform and make more efficient the ongoing planet hunting process, and also help us better understand our own Solar System’s formation.

When a star is young, it is surrounded by a rotating disk of gas and dust, from which its planets form. As such, it’s expected that chemical composition of the star should in some way affect the compositions of the planets orbiting it. Indeed, previous research has demonstrated that Jupiter-like gas giant planets preferentially form around iron-rich stars.

But do stars that form smaller planets have a similar chemical signature? This is the question a study led by Simon Schuler, a University of Tampa assistant professor of physics, set out to explore. The results were recently published in The Astrophysical Journal.

For the study, the team that includes former and present UT undergraduate students looked at the abundance of 19 elements in seven stars with small planets discovered by NASA’s Kepler mission. All but one star have been shown to have at least one planet of primarily rocky composition. Their findings suggest the formation of small planets does not require a particular host-star composition and that small planets may be ubiquitous in the galaxy.

“There has been much ongoing debate about the stellar conditions necessary for planet formation,” said Schuler. “Our results support the theory that the formation of small, rocky planets can occur around stars with diverse elemental composition.”

Schuler said the sample size for this study was relatively small, so the next step would be to expand the study to a larger group of stars in order to improve the statistical significance of their results.

For more information, contact Schuler at sschuler@ut.edu or (813) 257-3362.

Portions of this article are from a news release by the Carnegie Institute.