A "Tatoine-like" planet orbiting two suns has been discovered

An international team of astronomers announced the discovery of a second planet in the circumbinary system (in which planets orbit two suns) from the rare multiple planet BEBOP-1. This planet was discovered using the transit method and was noticed because it passed in front of the brighter of the two stars on different occasions

Astronomers at the University of Birmingham have discovered a second planet, named BEBOP-1c, in the rare multi-planet circumbinary system BEBOP-1 or TOI-1338. This discovery, made using the Doppler method, is essential to expanding our knowledge about the formation of planets around two stars.

The newly discovered planet is called BEBOP-1c, after the project that collected the data. BEBOP means binary stars accompanied by planets. The BEBOP-1 system is also called TOI-1338.

"Tatoine-like planet" refers to a circumbinary planet, or a planet that orbits two stars in one place, a term that originates from the world of "Star Wars" where Tatooine, the home planet of the character Luke Skywalker, orbits two stars. Such planets are relatively rare in real-world astronomy, and their dynamics are very different from planets in single-star systems like ours.

In 2020, a circumbinary planet named TOI-1338b was discovered in the same system using data from the TESS Space Telescope (TESS), to which the Birmingham team also contributed. This planet was discovered using the transit method and was noticed because it passed in front of the brighter of the two stars on different occasions.

"The transit method allowed us to measure the size of TOI-1338b, but not its mass, which is the most fundamental parameter of the planet," said lead author Dr Matthew Standing, who completed his PhD at the University of Birmingham and is now a researcher at the Open University.

At that time, the BEBOP team was already following this system using another method - the Doppler method. This method, also called the radial velocity method, relies on a precise measurement of the velocity of stars.

"This is the same method that led to the discovery of the first planet, for which Mayur and Kvaloz received the Nobel Prize in 2019," said Professor Emory Triaud of the University of Birmingham, who was Matthew's boss at the time.

Using the latest instruments installed in two telescopes located in the Atacama Desert in Chile, the team tried to measure the mass of the planet discovered by Tess. Despite their best efforts, and years of work, the team was unsuccessful, but instead they discovered a second planet, BEBOP‑1c, and measured its mass.

"Only 12 circumbinary systems are known so far, and this is only the second to host more than one planet," said David Martin, an astronomer at Ohio State University.

"The orbital period of BEBOP-1c is 215 days and its mass is 65 times greater than the Earth, which is about five times less than the mass of Jupiter," continues Dr. Standing. "It was difficult to verify this system, and our observations were interrupted by the corona epidemic when the telescopes in Chile were closed for six months in a critical part of the planet's orbit. It was possible to view this part of the track again last year, when the discovery became final."

Only two planets are currently known in the TOI-1338/BEBOP-1 circumbinary systems, but more may be identified in the future, through observations similar to those made by the team.

More of the topic in Hayadan:

• The double sunset Luke Skywalker saw on Tatooine is no fantasy
• Surprise: a planet with three suns
• Tatooine on the brink of destruction - a sand dune threatens the photo set in Tunisia
• A newly confirmed planet is the largest yet orbiting two suns
• One planet - two suns, and it's not Tatooine