Scientists are baffled by a mysterious planet as it survived the explosion of its star that should have left it obliterated.
Scientists are baffled by a mysterious planet as it survived the explosion of its star that should have left it obliterated
Located around 520 light years away from Earth, intensely hot Halla was discovered in 2015 and bears a resemblance to Jupiter.
Using the Transiting Exoplanet Survey Satellite, a research team found the star near Halla had previously transformed into a red giant star, a phenomenon known for wiping everything in its path.
But Halla miraculously endured this cataclysmic event.
This discovery – included in a study published in the journal Nature – has led scientists to speculate that there could be other similarly resilient planets scattered throughout the galaxy.
Marc Hon, a NASA Hubble fellow at the University of Hawaii at Manoa and one of the study's authors, referred to Halla as a “forbidden planet”.
He added the star itself might have an exceptional history that somehow allowed Halla to survive despite its close proximity to an inhospitable host star. Researchers used multiple telescopes on Maunakea to corroborate the existence of Halla.
Initially, they believed the planet was doomed when observations indicated that its star, named Baekdu, had depleted its hydrogen fuel, typically leading to expansion and destruction.
Subsequent investigations revealed Halla continued to exist within its 93-day orbit around the dying star.
The report acknowledges that when stars transition into red giants, they usually engulf planets located nearby.
Given that Halla is only 0.5 astronomical units (AU) away from its host star, it should have been destroyed when the star expanded to a radius of 0.7 AU during its evolution.
Theories for its survival include the possibility it is a young planet formed when two stars produced a gas cloud from which the planet eventually emerged.