Astronomers find place with two suns just like Tatooine in Star Wars

By Chris Dyer via SWNS

A new solar system has been found where planets orbit two suns - just like Luke Skywalker's home in Star Wars.

Astronomers say the rare find is only the second ever solar system discovered where planets move around more than one star.

It mimics Tatooine - the desert home planet of Luke and Anakin Skywalker in the Star Wars movie franchise - that famously has a double sunset.

The newly discovered system - unearthed by astronomers at the University of Birmingham - is called BEBOP-1c, after the name of the project that collected the data.

BEBOP stands for Binaries Escorted By Orbiting Planets and the BEBOP-1 system is also known as TOI-1338.

David Martin, an astronomer and Sagan Fellow at the Ohio State University said: “Only 12 circumbinary systems are known so far, and this is only the second that hosts more than one planet.”

Three years ago the researchers found another planet orbiting two suns called TOI-1338b, in the same system using data from NASA’s TESS space telescope, to which the Birmingham team also contributed.

It is now known that this planet has a density lower than a Victoria Sponge cake, a rarity that makes this planet optimal for further studies with the James Webb space telescope.

That planet was unearthed using the transit method, meaning it was spotted when the planet passed between a star and the observer.

In this case, it was noticed because it passed in front of the brighter of the two stars on several occasions, scientists said.

Study lead author Dr. Matthew Standing, who completed his Ph.D. at the University of Birmingham and is now a researcher at The Open University, said: “The transit method permitted us to measure the size of TOI-1338b, but not its mass which is the planet’s most fundamental parameter.”

The BEBOP team was already monitoring this system using another detection method at the time, called the Doppler method.

This method also called the wobble method, or radial-velocity method, relies on accurately measuring the velocity of stars.

Professor Amaury Triaud, Dr. Standing’s then supervisor at the University of Birmingham, said: “This is the same method that led to the first exoplanet detection, for which Mayor and Queloz received the Nobel Prize in 2019.”

Using state-of-the-art instruments installed on two telescopes in the Atacama Desert in Chile, the team tried to measure the mass of the planet noticed by TESS.

Despite their best efforts following years of work, the team could not achieve their goal, but instead discovered a second planet - BEBOP-1c - and measured its mass.

Dr. Standing added: “BEBOP-1c has an orbital period of 215 days, and a mass 65 times larger than Earth, which is about five times less than Jupiter’s mass.

“This was a difficult system to confirm, and our observations were interrupted by the COVID pandemic when telescopes in Chile closed for six months during a critical part of the planet’s orbit. This part of the orbit only became observable again last year, when we finalized the detection.”

At the moment only two planets are known in the TOI-1338/BEBOP-1 what's known as a 'circumbinary system' but more might be discovered in the future, with similar observations, the research team said.

Although rare, circumbinary planets are important in pushing the understanding of what happens when a planet is created, according to scientists.

Dr. Lalitha Sairam, a researcher at the University of Birmingham and second author of the study, said: “Planets are born in a disc of matter surrounding a young star, where mass progressively gathers into planets.

"In the case of circumbinary geometries, the disc surrounds both stars. As both stars orbit one another, they act like a giant paddle that disturbs the disc close to them and prevents planet formation except for in regions that are quiet and far away from the binary. It is easier to pinpoint the location and conditions of planet formation in circumbinary systems compared to single stars like the Sun.”

The team does not yet know the size of BEBOP-1c - only its mass - but researchers will try using the transit method to now measure its size.

Despite not detecting the inner planet - TOI-1338b - the team was able to put strict upper limits on its mass, researchers said.

If these observations happen, they might reveal the chemical environment in which this rare circumbinary planet formed.

The findings were published in the journal Nature Astronomy.