Find challenges theory that such a massive body cannot form around a small stellar host
Scientists have discovered a ‘monster’ planet orbiting a small, distant star, a finding that defies theories which state that such a massive planetary body cannot form around a small stellar host. According to these theories, small stars can readily form rocky planets but do not gather enough material together to form Jupiter-sized planets.
The newly discovered planet ‘NGTS-1b’ however, is a ‘gas giant.’ Due to its size and temperature, the planet is known as a ‘hot Jupiter’, a class of planets that are at least as large as our solar system’s very own Jupiter, but with around 20% less mass.
Unlike Jupiter, NGTS-1b is very close to its star — just 3% of the distance between Earth and the Sun, and completes an orbit every 2.6 days, meaning a year on NGTS-1b lasts two and a half Earth-days. In contrast, the host star is small, with a radius and mass half that of our Sun.
“Despite being a monster of a planet, NGTS-1b was difficult to find because its parent star is so small and faint,” said Peter Wheatley from the University of Warwick in the U.K.
The significance of the discovery is given the challenging circumstances “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 be found,” Wheatley said.
Using these data, 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. In fact, this method, measuring how much the star ‘wobbles’ due to the gravitational tug from the planet, was the best way of measuring NGTS-1b’s size, researchers said.PTI
Source: The Hindu