Massive ‘monster planet’ found orbiting puny star leaves astronomers stunned

Monster planet found orbiting dwarf star: ‘surprised’ astronomers

The existence of the gassy giant challenges long-standing theories that such a big planet — about the size of Jupiter — cannot be formed around a star so small.

The star has a radius and mass about half that of the sun.

Theory had predicted that small stars can form rocky planets, “but do not gather enough material together to form Jupiter-sized planets,” Britain’s Royal Astronomical Society said in a statement.

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Tau.Neutrino said:

The star has a radius and mass about half that of the sun.

If both its radius and mass are half that of the sun it must be bloody dense.

http://exoplanet.eu/catalog/ngts-1_b/

Radius is about 0.573 of the sun’s, mass is 0.617 of the sun’s. So the density is about 3.3 times that of the sun.

It is also somewhat colder than the sun, with an effective temperature of 3916 K compared to the sun’s : 5772 K.

Perhaps it was the failed twin of a binary star

Cymek said:

Perhaps it was the failed twin of a binary star

That’s what I was thinking. Note, though, that the star in this case is still about 700 times more massive than the planet.

> The existence of the gassy giant challenges long-standing theories that such a big planet — about the size of Jupiter — cannot be formed around a star so small.

Cymek said:

Perhaps it was the failed twin of a binary star

Yep.