Exoplanets continue to demonstrate how awesome and wonderful the universe truly is and using science fiction as analogs makes these discoveries all the more awesome. Nearly every fan of science fiction knows about the famous scene in the original Star Wars showing Tatooine farm boy and future Jedi Knight, Luke Skywalker, gaze into the double sunset, captivating audiences to this very day. This famous scene in cinema is what makes a recent exoplanet discovery even better.
Exoplanets that orbit two stars are known as circumbinary planets, and a recent study in the Monthly Notices of the Royal Astronomical Society has identified one such exoplanet using a ground-based telescope through the radial velocity method—measuring wobbles in a parent star as a planetary body orbits it. This exoplanet, known as Kepler-16b, originally discovered by the Kepler Telescope in 2011, is located just 245 light years from Earth. While Kepler-16b was initially discovered using the transit method—measuring dips in a star’s light as an exoplanet passes in front of it—this study demonstrates the ability to observe an exoplanet using more traditional methods with greater efficiency and far cheaper than using spacecrafts.
Planetary formations have long been theorized to begin with what’s known as planetary accretion, where materials within a protoplanetary disc—early solar system—literally clump together and eventually spin fast enough to form a planet. However, the existence of exoplanets in circumbinary systems are causing scientists to question these long-standing formation processes.
"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,’ said Professor Amaury Triaud of the University of Birmingham, who also led study. "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."
"Our discovery shows how ground-based telescopes remain entirely relevant to modern exoplanet research and can be used for exciting new projects,” said Dr Isabelle Boisse from the University of Marseille in France, who is also the scientist in charge of the SOPHIE instrument that was used to collect the study’s data. “Having shown we can detect Kepler-16b, we will now analyze data taken on many other binary star systems, and search for new circumbinary planets."
The team plans to continue searching for previously unknown circumbinary planets with the goal of answering questions as to how planets are formed.
Sources: Monthly Notices of the Royal Astronomical Society, Labroots, NASA