A new catalog of exoplanets from two telescopes shows the incredible variety of planets that exist beyond our solar system. The catalog, using data from NASA’s TESS (Transiting Exoplanet Survey Satellite) space telescope and the ground-based W. M. Keck Observatory, shows 126 planets, along with the radius, mass, density and temperature of each.
“Relatively few of the previously known exoplanets have a measurement of both the mass and the radius. The combination of these measurements tell us what the planets could be made of and how they formed,” explained Stephen Kane, University of California, Riverside astrophysicist and principal investigator of the TESS-Keck Survey, in a statement. “With this information, we can begin to answer questions about where our solar system fits in to the grand tapestry of other planetary systems.”
Among the exoplanets in the catalog are worlds like TOI-1798 c, shown at the top of this page, which orbits extremely close to its star and is bombarded by intense radiation as a result.
“TOI-1798 c orbits its star so quickly that one year on this planet lasts less than half a day on Earth. Because of their proximity to their host stars, planets like this one are also ultra hot — receiving more than 3,000 times the radiation that Earth receives from the sun,” said one of the catalog researchers, Alex Polanski of the University of Kansas.
Exoplanets like this one are unlikely to have any atmosphere as the intense radiation from their host stars would strip it away. But other worlds are more potentially hospitable, such as those orbiting small, cool stars called red dwarfs.
One big open question in exoplanet research is how typical our solar system is. The most commonly discovered exoplanets are gas giants, because their large size makes them easier to spot from extreme distances. But we don’t know how common Earth-sized worlds are because these are harder to identify in distant star systems due to their smaller size.
There is also a class of planet called sub-Neptunes which appear to be common elsewhere. “Planets smaller than Neptune, but larger than Earth are the most prevalent worlds in our galaxy, yet they are absent from our own solar system. Each time a new one is discovered, we are reminded of how diverse our universe is, and that our existence in the cosmos may be more unique than we can understand,” said Daria Pidhorodetska, also of UC Riverside.
Catalogs like this one help to show our place in the universe and the variety of planets out there. “Are we unusual? The jury is still out on that one, but our new mass catalog represents a major step toward answering that question,” Kane said.
The research is published in The Astrophysical Journal Letters.
