- Astronomers have discovered a frozen planet with a mass over three times that of the Earth, orbiting the closest solitary star to the Sun.
- The potentially rocky planet, known as Barnard’s star b, is a ‘super-Earth’ and orbits around its host star once every 233 days, said researchers from Queen Mary University of London in the UK.
- The findings, published in the journal Nature, show the planet lies at a distant region from the star known as the ‘snow line’.
- This is well beyond the habitable zone in which liquid water, and possibly life, could exist, researchers said.
- About Barnard’s Star :
- Named for astronomer E. E. Barnard, Barnard’s Star is the closest single star to the Sun. While the star itself is ancient probably twice the age of our Sun.
- Barnard’s Star is a red dwarf, a small and cooling star and produces relatively little light making it hard to discern any bodies in its orbit.
- At nearly six light-years away Barnard’s star is the next closest star to the Sun after the Alpha Centauri triple system.
- It is at least 3.2 times heavier than Earth and is the second nearest to Earth outside the solar system.
- Despite being relatively close to its parent star, the planet receives less than two per cent of the energy Earth gets from the Sun.
- Researchers estimates that it has a surface temperature of -170 degrees Celsius (-274 Fahrenheit) which makes it inhospitable.
- It’s thought that Barnard’s Star is tearing through space at around 500,000 km/h, making it the fastest moving known object in the universe.
- Radial velocity method:
- The researchers used the radial velocity method during the observations that led to the discovery of Barnard’s star b.
- This technique detects wobbles in a star which are likely to be caused by the gravitational pull of an orbiting planet.
- These wobbles affect the light coming from the star.
- As the star moves towards the Earth its spectrum appears slightly shifted towards the blue and, as it moves away, it is shifted towards the red.
- This is the first time that this technique has been used to detect a planet this small so far away from its host star.