Closest Star to Earth May Host Potentially Habitable Planet

Astronomers have discovered that a sun-like star closest to Earth may be hosting five planets, including one located within the habitable zone of the star.

Tau Ceti, a star that is identical to the sun, is located 12 light years away from Earth and can be seen through the naked eye in the evening sky. An international team of astronomers have detected that five planets may be orbiting Tau Ceti, with each planet estimated to have masses between two and six times the mass of the Earth. This makes it the lowest planetary system to have ever been detected so far.

One of the five planets is orbiting its star every 168 days and is located in the habitable zone of the star, where liquid water can exist on the planet's surface. The mass of this planet is five times that of the Earth's mass, making it the smallest planet to be detected in a habitable zone of any sun-like star.

"This discovery is in keeping with our emerging view that virtually every star has planets, and that the galaxy must have many such potentially habitable Earth-sized planets," coauthor Steve Vogt, a professor at the University of California Santa Cruz, said in a statement.

"We are now beginning to understand that nature seems to overwhelmingly prefer systems that have multiple planets with orbits of less than 100 days. This is quite unlike our own solar system, where there is nothing with an orbit inside that of Mercury. So our solar system is, in some sense, a bit of a freak and not the most typical kind of system that Nature cooks up."

Scientists found the planetary system using state-of-the-art instruments on telescopes located in Chile, Australia and Hawaii. They made 6,000 observations of Tau Ceti and used new techniques to detect tiny wobbles believed to have been caused by planets while orbiting the star, according to a report in USNews.

Until now, more than 800 planets have been discovered orbiting stars other than the sun. But finding a planetary system in a nearby sun-like star makes it interesting and more valuable, said the researchers.

"Tau Ceti is one of our nearest cosmic neighbors and so bright that we may be able to study the atmospheres of these planets in the not-too-distant future. Planetary systems found around nearby stars close to our Sun indicate that these systems are common in our Milky Way galaxy," said James Jenkins of Universidad de Chile, a visiting fellow at the University of Hertfordshire, U.K.

The findings of the study will appear in the journal Astronomy & Astrophysics.