Newly discovered ‘monster’ planet shouldn’t exist, according to science

31 Oct 2017

Artist’s impression of the cool red star above NGTS-1b. Image: Mark Garlick/University of Warwick

Our theory on how planets formed has just taken a massive knock after the discovery of a ‘monster’ planet that shouldn’t exist.

Every so often, astronomers discover something in the universe that is out of kilter with what we consider to be the natural laws, such as a star whose brightness dips irregularly.

Now, a new planet dubbed NGTS-1b is fundamentally challenging our theory of planet formation as this ‘monster’ is considerably larger than its parent star, which has a mass half that of the sun.

Until now, it was believed that a small star equal in size to this latest example could produce small, rocky planets, but nowhere near on a scale as large as NGTS-1b.

In a paper published to the journal Monthly Notices of the Royal Astronomical Society, a team from the University of Warwick revealed that NGTS-1b is a gas giant that is about as large as Jupiter, but has approximately 20pc less mass.

Unlike Jupiter, however, the planet is very close to its star at just 3pc of the distance between Earth and the sun, meaning it completes a year in less than three days.

How common are these planets?

The bizarre planet was first spotted by the Next-Generation Transit Survey (NGTS), which employs an array of 12 telescopes to scour the sky. In this instance, it spotted periodical dips in brightness, indicating the existence of a planet.

They then tracked the planet’s orbit and calculated the size, position and mass of NGTS-1b by measuring the radial velocity of the star, despite the fact that its small size made it difficult to spot.

Speaking of the implications of such a find, lead author of the study, Dr Daniel Bayliss, said: “The discovery of NGTS-1b was a complete surprise to us. Such massive planets were not thought to exist around such small stars.

“Importantly, our challenge now is to find out how common these types of planets are in the galaxy and, with the new NGTS facility, we are well placed to do just that.”

Colm Gorey was a senior journalist with Silicon Republic