'Tatooine-like' planet would have two sunsets for anyone on it

A study on the latest observations of the planet titled "BEBOP III. Observations and an independent mass measurement of Kepler-16 (AB) b - the first circumbinary planet detected with radial velocities" has been published in the journal Monthly Notices of the Royal Astronomical Society.

A team of researchers led by the University of Birmingham have used the 193-centimeter telescope at the Observatoire de Haute-Provence in France to observe the rare exoplanet. The planet is called Kepler-16b and previously had only been observed by the Kepler space telescope. It is located roughly 245 light-years away from Earth and orbits around two stars, which both orbit each other to create a binary star system.

Existing in such a system means that any observer on the surface of Kepler-16b would witness two sunsets (and sunrises), as you would on the planet Tatooine in the Star Wars universe. Kepler-16b was the fourth confirmed circumbinary planet (orbiting two stars) found at the time of discovery in 2011, with nine currently known at the time of writing.

The team used the radial velocity method, where astronomers observe changes in a star's velocity due to an orbiting planet, to detect Kepler-16b. This demonstrates the ability to use more traditional methods to locate other circumbinary stars with greater efficiency and lower cost than spacecraft. They plan to use the technique to find more circumbinary planets and understand how they form, as the conventional explanation using protoplanetary discs may not apply to such a system.

"Using this standard explanation it is difficult to understand how circumbinary planets can exist. That's because the presence of two stars interferes with the protoplanetary disc, and this prevents dust from agglomerating into planets, a process called accretion. The planet may have formed far from the two stars, where their influence is weaker, and then moved inwards in a process called disc-driven migration-or, alternatively, we may find we need to revise our understanding of the process of planetary accretion," said team leader Professor Amaury Triaud, from the University of Birmingham.

"Our discovery shows how ground-based telescopes remain entirely relevant to modern exoplanet research and can be used for exciting new projects. Having shown we can detect Kepler-16b, we will now analyse data taken on many other binary star systems, and search for new circumbinary planets," said Dr. Isabelle Boisse from the University of Marseille.

You can read more from the study here.