New insights into seasons on a planet outside our solar system

Thu, 13 Jan 2022 19:10:55 GMT
Space Daily

Montreal, Canada (SPX) Jan 14, 2022 Imagine being in a place where the winds are so strong that...

The eccentric orbit of the planet also leads to seasonal variations hundreds of times stronger than what we experience on Earth.

In a recent paper, a McGill-led research team, provides new insight into what seasons looks like on a planet outside our solar system.

The findings will potentially advance both the scientific understanding of how exoplanets form and evolve and give some context for planets in our own solar system.

The first scenario fits better with theories about how planets in our own solar system are born, but what would drive these types of planets to migrate so close to their parent stars remains unclear.

To test those ideas, the authors of a recent McGill-led study used data from NASA's retired Spitzer Space Telescope to look at the atmosphere of exoplanet XO-3b. They observed eccentric seasons and measured wind speeds on the planet by obtaining a phase curve of the planet as it completed a full revolution about its host star.

Looking at atmospheric dynamics and interior evolution "This planet is an extremely interesting case study for atmospheric dynamics and interior evolution, as it lies in an intermediate regime of planetary mass where processes normally neglected for less massive hot Jupiters may come into play," says Lisa Dang, the first author of a paper published recently in The Astronomical Journal, a PhD student at McGill University's Department of Physics.

Nicolas Cowan, a McGill professor explains: "The entire planet receives three times more energy when it is close to its star during a brief sort of summer, than when it is far from the star."

The researchers also re-estimated the planet's mass and radius and found that the planet was surprisingly puffier than expected.

Spitzer observations also hints that the planet produces much of its own heat as XO-3b's excess thermal emission isn't seasonal - it's observed throughout the year on XO-3b. It's possible that the excess warmth is coming from the planet's interior, through a process called tidal heating.

The star's gravitational squeeze on the planet oscillates as the oblong orbit takes the planet farther and then closer to the star.

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