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According to ScienceAlert (This article and its images were originally posted on ScienceAlert October 16, 2018 at 02:44AM.)
A wee baby star at the tender age of just 2 million years has revealed itself to be quite the precocious little cosmic object.
Astronomers have discovered it has not one, but four planets in the protoplanetary disc of dust and gas that surrounds it – and they are all gargantuan, with the biggest coming in at 11 times the mass of Jupiter, and the smallest about the mass of Saturn.
Moreover, their orbits are incredibly distant. The outermost is more than 1,000 times the distance from the star than the innermost. That’s the most extreme range of orbits ever observed in a planetary system; Pluto, for context, is only around 102 times the distance from the Sun as Mercury.
The star is named CI Tau, located around 500 light-years away in a star-forming region of the constellation of Taurus, and it’s been a bit of a brain teaser since 2016. That’s when the first of its planets – the largest of the four, the super-Jupiter named CI Tau b – was discovered, orbiting really close to the star, completing a full orbit every 9 days.
Because it’s so close, it’s what is known as a “hot Jupiter,” which is a type of planet that shouldn’t exist according to current models of planetary formation. That’s because gas giants can’t form that close to their host star – gravity, radiation and stellar winds prevent the gas from coalescing. Yet exist they do, seen orbiting about 1 percent of stars.
One explanation for their existence is that hot Jupiters start to form much farther out, then migrate inwards – but the estimated timescale for this is hundreds of millions of years, not two.
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