Detection of 'Super-Earth' Leads the Hunt for Habitable Exoplanets

Astronomers using a ground-based telescope for the first time have detected a "super-Earth" transit, a breakthrough that may lead the hunt for habitable exoplanets in the coming years, according to a new study.

When the exoplanet 55 Cancri e, located 40 light-years away from Earth, passed in front of a bright, nearby Sun-like star, an international research team was able to measure the event. Though scientists had already known of this exoplanet's existence, previous observations of its transit had relied on space-born telescopes. But this time around researchers used the state-of-the-art Nordic Optical Telescope on the island of La Palma, Spain.

"With this result we are also closing in on the detection of the atmospheres of small planets with ground-based telescopes," co-author Mercedes Lopez-Morales of the Harvard-Smithsonian Center for Astrophysics (CfA), said in a statement. "We are slowly paving the way toward the detection of bio-signatures in Earth-like planets around nearby stars."

During its transit, 55 Cancri e crosses its host star and blocks of a small fraction of its starlight, dimming the star by 1/2000th or 0.05 percent of its usual intensity. Until now, such a slight shadowing has only been measurable from space, where the lack of atmosphere allows for more precise measurements.

"It's remarkable what we can do by pushing the limits of existing telescopes and instruments, despite the complications posed by the Earth's own turbulent atmosphere," added study co-author Ray Jayawardhana.

The planet 55 Cancri e is about twice as big and eight times as massive as Earth, causing scientists to dub it as a "super-Earth." Despite its size, it's actually the smallest planet detected with this ground-based technique, raising hope that it could be used to search for other Earth-like worlds in the future.

It is the innermost of five planets known to circle the star, taking just 18 hours to make one complete orbit. Due to this fact the exoplanet boasts temperatures over 3,100 degrees Fahrenheit (1,700 Celsius), hot enough to melt metal. 55 Cancri e may be Earth-like, but it is hardly habitable for humans.

Still, astronomers expect to discover many more super-Earths in the next several years, perhaps with more promising conditions. NASA's TESS (Transiting Exoplanet Survey Satellite) will launch in 2017 and the European Space Agency's PLATO mission is scheduled to take off in 2024, both searching for transiting terrestrial planets around nearby bright stars.

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