Scientists are perplexed by a mysterious planet that was supposed to be destroyed, but they think they have figured out why it survived.
In the Milky Way, the planet known as 8 Ursae Minoris b was discovered in 2015.
But it shouldn't have been visible to us because it ought to have been swallowed up by a nearby dying star.
According to current theories, 8 Ursae Minoris b avoided that fate because it once shared space with a companion that prevented it from growing.
"This planetary system is unlike any other that has been found. The fact that this is the first makes it particularly noteworthy, according to astrophysicist Dimitri Veras of the University of Warwick, who worked with lead investigator Marc Hon of the University of Hawaii.
By discussing the future of our own solar system, the scientists explain their theories.
Our solar system's other planets and the Earth revolve around the sun, a star that burns gases.
Currently burning hydrogen, the sun is what is known as a yellow dwarf, but eventually it will begin to die. When that occurs, it will turn into a red giant and significantly expand, consuming Mercury, Venus, and perhaps Earth.
That destruction by an expanding star is exactly what 8 Ursae Minoris b should have experienced.
Marc Hon, who made the observations using the TESS space telescope, claims that a companion star appears to have saved the planet.
The planet is thought to have once circled two stars that were in different stages of life.
One of them was a red giant, a star that burns hydrogen until it becomes so hot that its helium core ignites and it begins to contract. The second star was an older white dwarf star that was burning helium.
According to the researchers, the red giant's helium core was ignited when it ingested its companion star, halting the red giant's rapid expansion.
Then, 8 Ursae Minoris b was free to carry on orbiting the combined star.
Dr. Hon explains that the concept of a binary star merger was developed through the process of solving a puzzle.
Following his observations, he collaborated with theorist Dimitri Veras and a team of about 40 scientists to determine potential explanations for the planet's survival.
Another hypothesis put forth by the researchers is that the planet was created by material that was ejected violently during the merger of the two stars.
But they claim that this is a far more speculative notion.
We still don't fully understand how planets might form around most stars, which are in binary systems. Due to the influence of binary companions, it is conceivable that a great number of additional bizarre planetary systems may exist.
The scientific publication Nature features the findings.
