A new catalog of exoplanets of two telescopes shows the incredible variety of planets that exist beyond our solar system. The catalog, which uses data from NASA’s TESS (Transiting Exoplanet Survey Satellite) space telescope and the WM Keck Observatory, shows 126 planets, along with the radius, mass, density and temperature of each one.
“Relatively few of the previously known exoplanets have a measurement of both mass and radius. The combination of these measurements tells us what the planets could be made of and how they formed,” explained Stephen Kane, an astrophysicist at the University of California, Riverside 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 into the great 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 orbit extremely close to its star and are bombarded by intense radiation as a result.
«TOI-1798 c orbits its star so fast that a 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 ultrahot, receiving more than 3,000 times the radiation that Earth receives from the Sun,” said one of the catalog’s researchers, Alex Polanski of the University of Kansas.
Exoplanets like this are unlikely to have an atmosphere, as the intense radiation from their host stars would remove it. But other worlds are potentially more hospitable, such as those orbiting small, cool stars called red dwarfs.
A 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 detect from extreme distances. But we don’t know how common Earth-sized worlds are because they are harder to identify in distant star systems due to their smaller size.
There is also a class of planets called sub-Neptunes that seem to be common elsewhere. «Planets smaller than Neptune but larger than Earth are the most common worlds in our galaxy, however, they are absent from our own solar system. Every time a new one is discovered, we are reminded 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 help show our place in the universe and the variety of planets that exist. «Are we unusual? “The jury is still out on that, but our massive new catalog represents an important step toward answering that question,” Kane said.
The research is published in The Astrophysical Journal Letters.
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