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Wednesday, January 15, 2014

Super-Earths Have Land Continents and Oceans, Making Them Much Similar to Earth Than Previously Thought

"Super-Earths" were just recently found to be more common in the universe than previously known, but now the exoplanets are believed to be more Earth-like than ever.

Super-Earths get their name for having a similar makeup to our own planet and for being slightly larger as well. Recent studies have found them to exist more commonly in the universe and our own Milky Way Galaxy.

According to Space.com, a new study finds the tectonically active super-Earths have exposed continents of land surrounded by oceans. Like Earth, these exoplanets most likely store their water in the mantle, creating a stable environment similar to our planet.

"Super-Earths are expected to have deep oceans that will overflow their basins and inundate the entire surface, but we show this logic to be flawed," study researcher Nicholas Cowan said in a press release. "Terrestrial planets have significant amounts of water in their interior. Super-Earths are likely to have shallow oceans to go along with their shallow ocean basins."

Cowan, a postdoctoral fellow at Northwestern's Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), presented the study at the 223rd meeting of the American Astronomical Society last week.

For their study, Cowan and his colleagues created a model for water storage on these super-Earths. On Earth, the mantle is a rocky layer that accounts for the planet's mass and volume. On the super-Earth model, the larger mass and volume means a more powerful gravitational pull, but even with the enlarged size, the exoplanet still has a surface similar to Earth's.

"We can put 80 times more water on a super-Earth and still have its surface look like Earth," Cowan said in the release. "These massive planets have enormous seafloor pressure, and this force pushes water into the mantle."

For the model to be completed, the researchers will have to make up for two main inefficiencies. First, the model assumes the super-Earths have plate tectonics and, second, is assumes the water in the Earth's mantle, based on an estimate.

"These are the two things we would like to know better to improve our model," Cowan said in the release. "Our model is a shot from the hip, but it's an important step in advancing how we think about super-Earths."

Source: http://www.universityherald.com

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