This artist’s illustration shows the theoretical internal structure of the exoplanet GJ 3470 b. It is unlike any planet found in the Solar System. Image credit: NASA/ESA/L. Hustak (STScI)
Two NASA space telescopes have teamed up to identify, for the first time, the detailed chemical “fingerprint” of a planet between the sizes of Earth and Neptune. No planets like this can be found in our own solar system, but they are common around other stars.
The planet, Gliese 3470 b (also known as GJ 3470 b), may be a cross between Earth and Neptune, with a large rocky core buried under a deep crushing hydrogen and helium atmosphere. Weighing in at 12.6 Earth masses, the planet is more massive than Earth, but less massive than Neptune (which is more than 17 Earth masses).
Many similar worlds have been discovered by NASA’s Kepler space observatory, whose mission ended in 2018. In fact, 80 percent of the planets in our galaxy may fall into this mass range. However, astronomers have never been able to understand the chemical nature of such a planet until now, researchers say.
By inventorying the contents of GJ 3470 b’s atmosphere, astronomers are able to uncover clues about ...