The planet Kepler-16b was first discovered in 2011. Now, thanks to a new technique for detecting exoplanets using ground-based telescopes, astronomers have confirmed that it is indeed a real-world Tatooine , that is, the planet Kepler-16b. fictional rocky desert with two suns that was the home of Luke Skywalker in the “Star Wars” saga.
“Kepler-16b was first discovered 10 years ago by NASA’s Kepler satellite using the transit method, ” explained astronomer Alexandre Santerne of the University of Marseille, France.
How is this ‘Tatooine’ real?
Kepler16-b orbits its two parent stars, Kepler-16A and Kepler-16B, every 229 days at a distance similar to the 225-day orbit of Venus, in what we call a circumbinary orbit. The alien world is gaseous and about the size of Saturn and about 245 light-years distant from us.
While scientists already knew the planet existed, using a well-characterized and studied target is a good way to find out if the techniques work. Now, an international team of astronomers has just explained how they have successfully applied a previously unused technique to observe a planet orbiting two stars.
“This is confirmation that our method works,” says David Martin, a co-author of the study and a NASA Sagan Fellow in the Department of Astronomy at The Ohio State University. “And it creates an opportunity for us to apply this method now to identify other systems like this.”
Scientists have been able to detect the minute gravitational attraction that an exoplanet of this type exerts on one of its host stars , that is, through the wobble of one of its stars, a technique known as radial velocity, which gives us, given its tried and tested, a new tool to probe and explore these exotic worlds.
What exactly is the radial velocity method?
It is based on analyzing the light spectra produced by stars. In this case, it was with the Observatoire Terrestrial de Haute Provence. Each planet exerts its own gravitational influence on the star, causing the star to wobble a bit. The Sun does too, mainly influenced by Jupiter. When the data line wobbles, it tells us that there is a planet. And this is the first time it has been used to find planets outside our solar system that orbit two stars.
How do these types of planets form?
“The typical process of planet formation is thought to take place within a protoplanetary disk, a mass of dust and gas that surrounds a young star,” said Amaury Triaud of the University of Birmingham.
However, with this standard explanation the existence of circumbinary planets like this is complicated. Then?
“It is possible that the planet formed away from the two stars, where their influence is weakest, and then moved inward in a process called disk-driven migration, or alternatively, we may need to revise our understanding of the process of planetary accretion”, point out the authors in their study published in the journal Monthly Notices of the Royal Astronomical Society.
The advantage of discovering exoplanets by the radial velocity method using ground-based telescopes is that it is possible to discover new circumbinary planets very efficiently and at a much lower cost than by using space observatories such as Kepler , the “earth hunter” space telescope. NASA’s Exoplanets” which was released in March 2009.
“Having shown that we can detect Kepler-16b, we will now analyze the data taken in many other binary star systems and search for new circumbinary planets,” the experts conclude.
Referencia: Amaury H.M.J. Triaud et al. 2022. BEBOP III. Observations and an independent mass measurement of Kepler-16 (AB) b – the first circumbinary planet detected with radial velocities. Monthly Notices of the Royal Astronomical Society 511 (3): 3561-3570; doi: 10.1093/mnras/stab3712
