Astronomers say 8 Ursae Minoris b is an intriguing exoplanet that shouldn’t exist. Not only is the planet only half the Earth-Sun distance from its star, but it appears to have moved beyond the phase that should have caused its star to expand and destroy the planet. Yet 8 Ursae Minoris b somehow persists despite all plausible explanations.
So how exactly did this mysterious exoplanet defy its demise? Well, as Ars Technica explains, there are several possible explanations here, but none of them are very plausible. This is because astronomers who first discovered the planet said the planet may have survived extinction because its host star was distracted and swallowed a white dwarf instead.
Astronomers first discovered this exoplanet using the radial velocity method. This method observes changes in light from a star to try to determine if a planet is in orbit. When a planet pulls a star toward Earth, that pull causes the light to be slightly blue-shifted and red-shifted away by it. Exactly how big planets are is difficult to estimate because they never completely blueshift toward Earth.
Therefore, astronomers must learn more about the planet. Based on the readings they took, this exoplanet appears to be 1.6 times the mass of Jupiter, making it a fairly large planet. It is also very close to its star, half the distance between the Earth and the Sun. It is reported to make a complete revolution in just 93 days. So how did this exoplanet survive the death and expansion of its star?
One possible explanation is that 8 Ursae Minoris b has a much greater mass than its star; therefore, it is large enough to survive when surrounded by the star. However, there is only an eight percent chance for this to be the case. The most likely explanation, according to scientists, is that the planet originally orbited a binary star, and the current star was stripping the atmosphere of the other, preventing it from engulfing the planet.
This is still unconfirmed, but if this explanation turns out to be true, it will create even more mysteries for astronomers in the universe. Our understanding of planet formation is being challenged in other ways, so this discovery could add to the evidence that we really have no idea what’s going on in our universe.
Source: Port Altele
