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A spacecraft the size of a cereal box has collected precise measurements of the atmospheres of large and puffy planets called 鈥渉ot Jupiters.鈥� The findings, led by a team from CU听Boulder, could help reveal how the atmospheres around these and a host of other worlds are escaping into space.

The observations are the first results to come from a hard-working NASA spacecraft known as the (CUTE).听

Kevin France, principal investigator for the mission, will present the group鈥檚 results at a media availability Monday, Dec. 11, at 4:30 p.m. Pacific time during the in San Francisco.

The diminutive spacecraft, which measures just 14 inches in length, may be cute, but its . Since its launch in September 2021, CUTE has trained its single ultraviolet telescope at a series of hot Jupiters, some hundreds of light-years from Earth.

Hot Jupiters are among the hottest and angriest planets in the galaxy. As their name suggests, they are gas giants like our own Jupiter. These planets, however, hug much closer to their home stars, completing an orbit roughly once every several Earth days. In the process, stellar radiation cooks hot Jupiters to thousands of degrees Fahrenheit, and their atmospheres swell to enormous sizes, a bit like bread rising in an oven.听

Researchers have long suspected that this constant pummeling from stellar radiation could strip away the atmospheres from around some exoplanets over millions-to-billions of years. Data from CUTE suggest that the process might not be so simple.听

The CUTE team, which includes several undergraduate and graduate students, has observed seven hot Jupiters so far, with more on the way. Some of them seem to be losing their atmospheres, but others aren鈥檛.

鈥淭he planets seem to be coming in all of the flavors,鈥� said France, associate professor in the (LASP) and Department of Astrophysical and Planetary Sciences.

He added that CUTE is helping scientists to build out their field guide to the many kinds of planets that exist in the Milky Way Galaxy鈥攊ncluding those that look nothing like Earth鈥檚 close neighbors.

鈥淲e want to understand how our solar system fits into the family of solar systems in the universe,鈥� France said. 鈥淭hat means understanding the big planets, the small planets, the ones that could have life and the ones that definitely don鈥檛鈥攁nd all of the important physical processes that are operating on these planets.鈥�

Getting hot in here

CUTE鈥檚 road to scientific success wasn鈥檛 easy.

When the , France and his colleagues quickly noticed that it seemed to be experiencing a few glitches鈥攁 normal problem for many small satellites, or CubeSats, which often test out technology that鈥檚 never before flown into space. In one case, the shutter that protected CUTE鈥檚 telescope kept snapping shut when it wasn鈥檛 supposed to.听

The team, which included several undergraduate and graduate students, didn鈥檛 give up. The researchers commanded the spacecraft to open its shutter, then drained the battery that fed it, preventing the apparatus from shutting again.听

鈥淐UTE is still working and collecting data today,鈥� France said. 鈥淲hen we got our first real science results, it was really exciting.鈥�

CUTE observes distant planets as they pass in front of their home stars, causing ultraviolet light from those stars to dim in the process. In some cases, the spacecraft is so precise that it can detect when starlight dims by just 1%.听

In a , the researchers described their observations of a world called WASP-189b. This planet orbits a star in the constellation Libra more than 300 light-years, or thousands of trillions of miles, from Earth. It鈥檚 also incredibly toasty, with its atmosphere reaching temperatures of roughly 15,000 degrees Fahrenheit, according to the team鈥檚 results. That鈥檚 thousands of degrees hotter than the surface of the sun.

CUTE鈥檚 observations also suggest that gas is escaping from around WASP-189b at a similarly staggering rate of about 400 million kilograms (nearly 900 million pounds) per second.

Planets evolving

Not all of the planets CUTE has studied in its first two years were so exciting. In unpublished results, the team observed a second planet called MASCARA-4b that didn鈥檛 seem to be losing much gas at all. Others, like KELT-9b, fell somewhere in the middle.

France and his colleagues hope their results could help uncover why some planets lose big chunks of their atmosphere, while others remain mostly unchanged. He suspects that it has to do with a combination of the planets themselves (larger planets generate a stronger gravitational pull) and the dynamics of their stars (more active stars likely wreak more havoc on planets than sedate stars).

Those same processes potentially sculpt planets, both in and out of Earth鈥檚 solar system, over time. Scientists, for example, theorize that Mars once hosted a much thicker atmosphere, but the sun eroded it away over billions of years.听

Atmospheric escape may also explain the origin of a class of planets known as 鈥渟uper Earths,鈥� which are slightly larger than our own world.听

鈥淭here鈥檚 a lot of evidence that suggests that super Earths begin as planets the size of Neptune with large, puffy atmospheres, which then lose so much mass that all that is left is the rocky core and possibly a thin atmosphere,鈥� France said. 听

CUTE鈥檚 greatest legacy may be its impact on students, he said. The mission鈥檚 small team of about 20 people were involved in almost every aspect of the spacecraft鈥檚 life鈥攆rom building the satellite to launching it, sending it commands, then downloading and analyzing scientific data. CUTE is currently orbiting about 326 miles (525 kilometers) above Earth鈥檚 surface, and is expected to reenter the atmosphere by 2027.听

鈥淎ll of these things are what happens on big NASA missions, just on a much larger scale,鈥� France said. 鈥淥ur students and early-career scientists are getting the full experience from the proposal stage all the way to getting out the science product."