GJ 367b is the ultra small planet found by astronomers that is circling a dim red dwarf star. This star is 31 light years away from the sun.
The GJ 367b is a rocky planet, 70% the size of the earth and is 55% the mass of the earth. This makes GJ 367b one of the lightest known exoplanets.
This planet completes its orbit in 7.7 hours and hence is called the Ultra Short Period Planet which is dominated by an iron core. It is because of this reason the planet has high density and a disproportionately large core made of iron and nickel. This property of the planet is similar to Mercury.
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