Hot Jupiters are some of the most extreme planets in the universe, fiery gas giants like Jupiter or Saturn that exist so close to their stars that they complete orbits in a matter of days. Now, new research may rewrite the definition of these planets that make the solar system seem a little mundane.
The extrasolar planet, or exoplanetAt the center of this rethinking is CoRoT-2 b, a world with 3.5 times the jupiter mass and 1.5 times the size of the largest planet in our solar system, located about 696 light years away. It orbits its star in only approximately 41 hours.
What’s so strange about CoRoT-2 b? Has to Hot Jupiters They are tidally locked, meaning they have a side that permanently faces their stars, a “day side,” and a “night side” that faces space in perpetuity. However, new research from CoRoT-2 b appears to show that this hot Jupiter is not tidally locked, and that’s a big surprise, challenging all our assumptions about these. extreme exoplanets.
“I really like looking at strange planets, finding planets that don’t fit the standard picture, and solving some mysteries,” said team leader Aurora Kesseli of NASA’s Exoplanet Science Institute (NExScI). he said in a statement.
“We can now see that a one-size-fits-all model doesn’t work, even for planets we’ve been studying for a long time. Every time we look at another hot Jupiter, we learn something new that will help us refine our models, which are useful for understanding not just hot Jupiters, but all types of exoplanets.”
The cosmic dance of the hot Jupiters
For rocky planets, tidal locking would result in an incredibly hot dayside and a much colder nightside, divided by a perpetual sunset. However, the situation for gas giants is somewhat more complicated due to their swirling atmospheres.
This means that while hot Jupiters have day and night sides, they generally have large hot spots on the day side, slightly offset toward the direction of their rotation and orbit around the host star. CoRoT 2b also defines this expectation, as it has an access point in the opposite direction of its orbit. Kesseli and the team investigated three possible reasons for this anomaly.
“It is important for astronomers to understand the conditions for tidal locking because the habitable zone of the planets around Midgets “It’s within the tidally locked zone, where we expect tidally locked to occur fairly quickly,” Kesseli said. “The way a planet rotates greatly affects how the planet distributes its heat and therefore affects its habitability, so for a planet that is tidally locked, the temperatures, winds and climates will look completely different than a planet that is not tidally locked.”
By measuring the speed of CoRoT-2 b, Kesseli and his colleagues found that a day on this hot Jupiter lasts about three Earth days, almost twice as long as its year, which lasts about 1.5 Earth days. This means that its day is much shorter than its year; By the time CoRoT-2 b completes one rotation, it has traveled almost two orbits around its parent star.
“I was pleasantly surprised when I tried several methods and thought, ‘Aha! This is actually one of the three hypotheses!’ Seeing the data that clearly pointed toward one of them was really exciting,” Kesseli said.
Kesseli’s next step is to find out what is causing the slow rotation of CoRoT-2 b.
“Hot Jupiters are the first type of planet where we’ve been able to really explore and refine our models of their climates,” Kesseli said. “With the next generation of telescopes like the Observatory of habitable worlds and the Extremely large telescope“We will be able to perform deeper measurements on more planets, perhaps even potentially habitable planets.”
The team’s research was presented at the 248th meeting of the American Astronomical Society in Pasadena, California, and posted on the paper repository site. arXiv.
