Asked by Jonathan Rosewall
Hot Jupiters are heated gas giant planets that are very close to their stars, just a few million miles distant and orbiting their stellar hosts in just a few days. The reason why there isn’t one in our Solar System is down to its formation.
All gas giants form far from their star but then some migrate inwards. When they move closer, they push all the smaller planets in front of them either into the star or fling them out of the planetary system entirely. Planetary migration hinges on how thick the disc of gas and dust is and which planets are built. A thick disc will cause a planet to move closer to its star, while with a thinner disc, migration stops. Other planets in the system can also have an effect on a planet’s orbit.
In the case of our Solar System, its dust disc dissipated before Jupiter had the chance to move very far – thankfully!
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