University of Hawaii astronomers have discovered one of the youngest planets ever observed.
Using Maunakea telescopes, an international team of scientists led by UH-Manoa astronomers determined that a distant star 400 light years away is orbited by a planet estimated to be between 2-5 million years old, about as old as the Hawaiian Islands.
“It’s among the youngest planets to ever be observed,” said UH-Manoa professor Eric Gaidos, lead author on the study. “Since we don’t know the age of most (celestial) objects too precisely, we don’t like to make definitive statements that any object is definitely younger than any other. But it’s among the youngest, certainly.”
Gaidos said the planet’s age was determined by using the Keck Observatory to monitor the movements of its parent star.
The movements of that star were similar to other stars known to be young, and, because most planets are understood to form at about the same time as their host star, the planet is assumed to be about the same age as the parent star it orbits.
Little is known about the planet — designated 2M0437b — but researchers estimate that it is several times more massive than Jupiter, our solar system’s largest planet, which is about 318 times more massive than the Earth.
2M0437b also is known to orbit its star at a very long distance, about 100 times more distant from its host star than Jupiter is from our sun.
It also is about as hot as the lava in Kilauea, Gaidos said: The youth of the planet means it is still hot from the energy released during its formation.
However, more information about the planet can be gleaned soon. Gaidos said that, unlike most planets, reflected light from the planet is actually observable using Earth telescopes, meaning that astronomers can use a spectroscopic analysis to determine its atmospheric composition.
“We can guess at its atmosphere,” Gaidos said. “It’s probably not too dissimilar to Jupiter’s. But we don’t know for sure yet.”
Gaidos also said that based on the planet’s age, it could be in the process of forming moons.
With more observations, scientists could learn about the process by which satellites form in a planet’s orbit, and about the composition of its host star as well.
“We learn much about our solar system by constrasting ourselves with others,” Gaidos said. “It’s because of our differences that we can learn anything. If we all just had thousands of copies of our own solar system to work with, we’d never be able to learn anything.”
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