A ‘monster’ planet, which according to classic theories of planet formation shouldn’t exist, has been discovered orbiting a distant star.
Presented in a paper, by astronomers from the University of Warwick, the planet NGTS-1b is a gas giant, which because of its size and temperature has been dubbed ‘hot Jupiter’.
However, its existence challenges theories of planet formation that state planets of this size cannot be formed around such a small star.
NGTS-1b ‘s host star has a radius and mass that amounts to half of our sun.
The gap between NGTS-1b and its parent star is just 3% of the distance between Earth and the Sun, which means the planet completes an orbit every 2.6 days, so a year on NGTS-1b lasts just two and a half Earth-days.
“Despite being a monster of a planet, NGTS-1b was difficult to find because its parent star is so small and faint,” said professor Peter Wheatley from the University of Warwick. “Small stars like this red M-dwarf are actually the most common in the Universe, so it is possible that there are many of these giant planets waiting to found.”
The researchers discovered NGTS-1b by continually monitoring patches of the night sky over many months, and detecting red light from the star with innovative red-sensitive cameras.
They noticed dips in the light from the star every 2.6 days, implying that a planet was orbiting and periodically blocking the starlight.
Using this data, the astronomers then tracked the planet’s orbit and calculated the size, position and mass of NGTS-1b by measuring the radial velocity of the star. In other words, the team measured how much the star ‘wobbles’ due to the gravitational tug from NGTS-1b.
“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 Next-Generation Transit Survey facility we are well-placed to do just that,” said the study’s lead author, Dr Daniel Bayliss.
NGTS-1b is the first planet to be spotted by The Next-Generation Transit Survey (NGTS) which employs an array of 12 telescopes to scour the sky.
NGTS is situated at the European Southern Observatory’s Paranal Observatory in the heart of the Atacama Desert, Chile, but is one of very few facilities to be run by external parties – UK Universities Warwick, Leicester, Cambridge, and Queen’s University Belfast are involved, together with Observatoire de Genève, DLR Berlin and Universidad de Chile.
“Having worked for almost a decade to develop the NGTS telescope array, it is thrilling to see it picking out new and unexpected types of planets. I’m looking forward to seeing what other kinds of exciting new planets we can turn up,” said NGTS’s leader, professor Peter Wheatley.