NASA's Kepler Telescope Discovers First Known Tilted Star System

A team of international astronomers has discovered a distant star system that has multiple planets orbiting at a severe tilt to their host star.

On analyzing years of information gathered by NASA's exoplanet hunting Kepler Space Telescope that is currently out of service, the researchers discovered the unique misaligned planet in the distant system. The host star dubbed Kepler-56 is one of the 150,000 stars that have been under constant supervision by NASA for the last few years. The host star is about 3,000 light years away from Earth and is four times as wide as the Sun and is 30 percent more gigantic, reports NBC News.

"This is a new level of detail about the architecture of a planetary system outside our solar system. These studies allow us to draw a detailed picture of a distant system that provides a new and critical test of our understanding of how these very alien solar systems are structures," Steve Kawaler, a physicist at Iowa State University and a leader of the Kepler Asteroseismic Investigation, said in a press statement.

Prior to this finding, tilted orbits have been spotted earlier in planetary systems that have large planets orbiting close to the its host star also called as the 'hot Jupiters'. But this finding makes it the first of its kind as the tilts have been spotted in a multi planet system where the massive hot Jupiter is absent.

Kawaler studied the continuous changes occurring in the brightness of the Kepler-56, which is an aging red star, with two planets in close orbits and a giant third planet that is placed at a distant orbit. The researchers measured the star's diameter as well other intriguing properties by measuring the oscillation frequency and spectroscopy data of the star's chemistry and temperature.

The planet hunting Kepler identifies planets in the distant star systems by observing the changes in the brightness of light. The Kepler probe noticed two planets wide enough to mark them as gas giants, where the orbits lasted 10.5-21 Earth days. With asteroseismology, the probe studied the structure of the stars and revealed that the axis is tilted 45 degrees to the line of sight from Earth.

"It was a big surprise," lead author Daniel Huber of NASA's Ames Research Center told Nature.

To investigate the cause of such tilting, the researchers measured the velocity of Kepler-56 through space with the help of 10 meter Keck I telescope located in Mauna kea in Hawaii.

"That revealed the culprit- a distant body whose gravitational pull tugs the star and also tilts the planets' orbits," Huber says. "Despite the enormous tilt, the planets' orbits stay aligned with each other because they're in resonance: one planet takes twice as long as the other to circle the star, so they periodically nudge each other through their gravity. Their orbits therefore remain co-planar even as they deviate radically from the star's equator."

The findings were reported in this week's issue if the journal Science.