Two of NASA’s telescopes, Hubble and Spitzer teamed up to identify chemical fingerprint of a planet between the sizes of Earth and Neptune, NASA said on Tuesday.
In case you are wondering, the planet is named Gliese 3470 b or GJ 3470 b and it is thought to be a cross between Earth and Neptune. According to NASA, the planet is believed to have a large, rocky core buried under a hydrogen-and-helium atmosphere. As a result, the planet weighs in at 12.6 Earth masses although it is less massive than Neptune which is more than 17 Earth masses.
Although NASA’s Kepler space observatory has discovered similar planets in past before ending its mission back in 2017, astronomers were able to identify the chemical nature of such planets for the first time. Thanks to the telescopes’ latest discovery, the scientists can now uncover clues about GJ 3470 b’s nature and origin.
“This is a big discovery from the planet-formation perspective. The planet orbits very close to the star and is far less massive than Jupiter – 318 times Earth’s mass – but has managed to accrete the primordial hydrogen/helium atmosphere that is largely ‘unpolluted’ by heavier elements. We don’t have anything like this in the solar system, and that’s what makes it striking,” said Björn Benneke of the University of Montreal in Canada.
In order to find out the planet’s atmosphere, Hubble and Spitzer observed 12 transits and 20 eclipses to analyze chemical fingerprints using a method called ‘spectroscopy’. After analyzing the data, the researchers realized that the planet’s atmosphere is mostly clear with thin hazes that allowed the scientists to analyze the planet’s atmosphere further.
Although the group thought GJ 3470 b will have elements like oxygen and carbon, the planet turned out to contain atmosphere that doesn’t have extremely small number of heavy elements and the atmosphere’s composition is closer to the hydrogen/helium-rich composition of the Sun. While the scientists hope to discover more about the planet in future, they think that the planet gained its atmosphere from orbiting close to the host star.