A research team from the University of Birmingham has employed a ground-based telescope to observe an exoplanet called ‘Kepler-16b.’
What is Kepler-16b?
Kepler-16b is an exoplanet that, up until now, has only been detected utilising the Kepler space telescope.
The planet orbits around two stars, with the two orbits also orbiting one another, forming a binary star system. Kepler-16b is located approximately 245 light years from Earth and would have two sunsets if you could stand on its surface.
Dr Alexandre Santerne, from the University of Marseille, and a collaborator on the research said: “Kepler-16b was first discovered 10 years ago by NASA’s Kepler satellite using the transit method. This system was the most unexpected discovery made by Kepler. We chose to turn our telescope and recover Kepler-16 to demonstrate the validity of our radial-velocity methods.”
How did scientists detect this with the ground-based telescope?
The ground-based telescope—which is approximately 193cm— utilised in this new observation is based at the Observatoire de Haute-Provence, in France.
Researchers were able to detect the planet by employing the radial velocity method, which means that astronomers observed a change in the velocity of a star as a planet orbits around it.
The detection of Kepler-16b using the ground-based telescope and the radial velocity method is considered a significant development in the scientific community. This is because it represents an important demonstration that it is possible to detect circumbinary planets using more traditional methods, at greater efficiency and lower cost than by using spacecrafts.
Additionally, researchers consider the radial velocity method as the most beneficial due to the additional factors that this method allows scientists to observe such as, the opportunity to detect additional planets in a system, and the ability to measure the mass of a planet.
What do scientists intend to do with this discovery?
Having demonstrated the successful method in observing Kepler-16b, researchers plan to search for previously unknown circumbinary planets, with the ground-based telescope, and help answer questions about how planets are formed.
Typically, planet formation is thought to take place within a protoplanetary disc, which is a mass of dust and gas which surrounds a young star. However, this process may not be possible within a circumbinary system.
Professor Amaury Triaud, from the University of Birmingham, who led the team, explained: “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.”
Dr David Martin, from the Ohio State University (USA), and contributed to the discovery, noted “Circumbinary planets provide one of the clearest clues that disc-driven migration is a viable process, and that it happens regularly.”
Dr Isabelle Boisse, from the University of Marseille, and the scientist in charge of the SOPHIE telescope that was utilised to collect the data, concluded: “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.”
