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Astronomers discover a water-rich planet outside our solar system

A Japanese research team of astronomers and other planetary scientists have used the Subaru Telescope to determine whether the surface of a planet that scientists have deemed a “super Earth” is rich in hydrogen or water.

The telescope is equipped with two optical cameras, Suprime-Cam and the Faint Object Camera and Spectrograph (FOCAS), with a blue transmission filter that aided the scientists in their investigation. Super-Earth GJ 1214 b (Gilese 1214 b) did not present through the filter with the appearance that would have indicated its richness in hydrogen so after taking into consideration previous research, the scientists concluded that the planet was most likely water-rich.

Super Earths are a type of exoplanet (a planet orbiting a star outside our solar system) that have a mass and radius larger than Earth but are still smaller than other big planets in the solar system such as Neptune, a press release from the Subaru Telescope explains. Scientists are still in the process of learning about exoplanets, and much information about them remains locked away within the planets themselves. Because scientists do not know the composition of super Earths, they are unsure whether they are more like a big Earth, or a small planet.

This researchers set out to investigate the atmospheric properties of a super Earth, located 40 light-years away from our planet in the constellation Ophiucus. This particular super Earth was originally discovered by Charbonneau et. al. (2009) in the MEarth Project. The MEarth Project focuses on finding habitable planets near other stars.

Previous discoveries about super Earths, including where they have formed and how they migrated to their current spot in the sky, point to the idea that hydrogen or water vapor is a key component of the super Earth itself. By determining the super Earth’s composition, scientists are better able to identify where the super Earth originated from and how it formed. The team does not completely discount the possibility that hydrogen is the dominant molecule in the super Earth’s atmosphere, but their research points to water being a more significant component. They plan to continue their research to back up their conclusion.

The Transiting Exoplanet Survey Satellite (TESS) is set to begin exploring the sky for exoplanets soon, at which point the discovery of more super Earths may be imminent. By using the Subaru Telescope, along with the Thirty Meter Telescope, scientists will be able to greatly expand their knowledge base about super Earths, potentially discovering how they are formed and whether they could support life.