astronomy
Discovery of a planet with two suns
Like Tatooine, the world of Luke Skywalker in “Star Wars”, BEBOP-1C orbits binary stars.
Posted Jun 14, 2023 6:45am
From his home on Tatooine, Luke Skywalker sees two suns.
Lucas Films
Until 2011, astrophysicists believed there were no planets with twin suns like Tatooine in Star Wars. However, double stars or suns orbiting each other are very common, as they are more than half of the Sun-like stars in the Milky Way.
However, scientists believed that the presence of two stars was moving the planets’ birth disks too much for them to exist. But in 2011, the Kepler telescope discovered the planet that will inherit its name: Kepler 16-b, which has two suns.
More often than expected
Since then, 13 others have been discovered, including three in the same system, Kepler-47 in the Cygnus constellation, 5,000 light-years from Earth. In 2020, NASA’s TESS telescope discovered the planet TOI-1338b orbiting two stars 1320 light-years away. While attempting to determine its mass using the telescopes at the Atacama Observatory in Chile, scientists discovered a second planet in this system, the 15th previously known circumbinary planet. Of the 5,200 exoplanets discovered, these appear to be few, but astronomers now believe they are as common as planets around individual stars.
This newcomer has been dubbed BEBOP-1c, after the name of the research project BEBOP, Binaries Escorted By Orbiting Planets, Space.com explains. It is a gas giant 65 times the mass of Earth and orbiting its suns at 79% of Earth’s average distance from our Sun. It takes 215 days to complete one orbit.
A first with the radial velocity method
BEBOP-1c is the first circumbinary planet discovered using the radial velocity technique. The aim is to identify the presence of planets based on the oscillations of the orbits of the stars. The transit method is based on the difference in light that we perceive as a star passing in front of its sun.
“So far, circumbinary planets in transit have been discovered by the Kepler and TESS space telescopes, costing hundreds of millions of dollars,” said lead author of the Nature Astronomy study Matthew Standing, an astrophysicist at the Open University in England. For him, this shows that “you don’t need expensive space telescopes to discover these planets, but that it can be done with ground-based telescopes with careful planning and target selection.”
Aiding the discovery of BEBOP was the fact that its secondary star is much smaller and fainter than the primary star, so the two signals do not interfere with telescopes. But as detection techniques improve, circumbinary planets orbiting in systems with two stars of similar size may also be discovered in the near future, which is the most common.
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