'Tilted' exoplanets may be habitable if covered in oceans

A new study has recently revealed that exoplanets, whose axis is tilted, may still be habitable if they are covered in oceans.

Scientists at MIT have found that even a high-obliquity planet, with a nearly horizontal axis, could potentially support life, so long as the planets were completely covered by an ocean. In fact, even a shallow ocean, about 50 meters deep, would be enough to keep such a planet at relatively comfortable temperatures, averaging around 60 degrees Fahrenheit year-round.

David Ferreira, a former research scientist in MIT's Department of Earth, Atmospheric and Planetary Sciences (EAPS) and his colleagues used a model developed at MIT to simulate a high-obliquity "aquaplanet," an Earth-sized planet, at a similar distance from its sun, covered entirely in water.

The three-dimensional model was designed to simulate circulations among the atmosphere, ocean, and sea ice, taking into the account the effects of winds and heat in driving a 3000-meter deep ocean. For comparison, the researchers also coupled the atmospheric model with simplified, motionless "swamp" oceans of various depths: 200 meters, 50 meters, and 10 meters.

For a planet with an extreme, 90-degree tilt, they found that a global ocean, even one as shallow as 50 meters, would absorb enough solar energy throughout the polar summer and release it back into the atmosphere in winter to maintain a rather mild climate. As a result, the planet as a whole would experience spring-like temperatures year round.

The study is published in the journal Icarus.