An international consortium of astronomers has ushered in a new era in our understanding of the cosmos with the second-ever unearthing of a multi-planetary circumbinary system, a stellar arrangement resembling the iconic Star Wars locale, Tatooine. This groundbreaking revelation was published in the current edition of Nature Astronomy, spearheaded by scientists at the University of Birmingham.
Scientists have found a multi-planetary system that they say resembles Tatooine from Star Wars.
Think of a circumbinary system as a celestial dance, with planets pirouetting around a pair of waltzing stars rather than a lone one, as is the case in our Solar System. In a surprising twist to the story, our newly identified planetary member, dubbed BEBOP-1c, emerges from the shadows of the project that lent it its name, the BEBOP – an acronym for Binaries Escorted By Orbiting Planets.
The BEBOP-1 system, alternatively known as TOI-1338, had already made waves in 2020 with the discovery of a circumbinary planet, TOI-1338b, courtesy of data gleaned from NASA’s TESS space telescope and the keen eye of the Birmingham team. Noted for its multiple transits in front of the system’s brighter star, TOI-1338b remains an enigma due to the inability to gauge its mass accurately.
The Scientific Rigor Behind the Discovery
“The transit method allowed us to ascertain the size of TOI-1338b, but it couldn’t reveal its mass, the most crucial element of a planet,” clarified the study’s main author, Dr Matthew Standing, an alumnus of the University of Birmingham, currently holding a research position at The Open University. Simultaneously, the BEBOP team utilized the Doppler method to monitor the system, a technique that focuses on precisely measuring stellar velocity.
“This very methodology gave rise to the first exoplanet detection, an achievement that earned Mayor and Queloz the prestigious Nobel Prize in 2019,” acknowledged Professor Amaury Triaud, a mentor to Matthew Standing at the University of Birmingham.
Despite years of diligent work, the team’s attempt to quantify the mass of the TESS-identified planet remained fruitless. However, their persistence paved the way for discovering and measuring the mass of a second planet, BEBOP-1c.
The Rarity of Circumbinary Planets: a real life Tatooine?
“Circumbinary systems are few and far between, with just twelve identified to date, and ours being only the second to host more than one planet,” revealed David Martin, a renowned astronomer and Sagan Fellow at Ohio State University.
BEBOP-1c orbits its dual stars every 215 days and carries a mass roughly 65 times that of Earth, almost a fifth of Jupiter’s mass. Only two planets have been identified within the TOI-1338/BEBOP-1 system, but the potential for further discoveries remains a tantalizing prospect. These rare circumbinary planets are vital to enhancing our understanding of planetary formation.
Insights into Planet Formation
“Planets are birthed from a disc of matter enveloping a young star, where mass gradually conglomerates into planets,” explains Dr. Lalitha Sairam, a co-author of the study from the University of Birmingham. The disc engulfs both stars in circumbinary systems, providing an intriguing environment for observing planetary formation.
The size of BEBOP-1c remains an enigma, but researchers are now employing the transit method to measure it. Meanwhile, the team has established stringent upper limits for the mass of TOI-1338b. Its extraordinarily low density – less than a Victoria Sponge cake – deems it an ideal subject for further studies with the James Webb space telescope, potentially revealing the chemical milieu that gave rise to this unusual circumbinary planet.