‘Cooked’ Earths: NASA discovers exoplanets being stripped of their atmospheres

Written by Victoria Woollaston, www.dailymail.co.uk on April 11, 2016. Posted in Current News

Decades of space missions have provided us with clues about atmospheres around planets within our own solar system, and now they’re starting to reveal more about planets that don’t orbit our sun.

Using data from the Nasa Kepler space telescope, astrophysicists have discovered a class of exoplanets whose atmospheres have been stripped away by their host stars.

Dubbed hot super-Earths, these planets are losing their layers of gas because of blasts of intense radiation that ‘cooks’ the large stellar bodies.

Astrophysicists used data from the Nasa Kepler space telescope to discover a class of exoplanets whose atmospheres have been stripped away by their host stars. Artist’s illustration pictured. Due to their proximity to their host star, the heat the planets suffer means their ‘envelopes’ have been blown away by radiation

Astrophysicists at the University of Birmingham used data from the Nasa Kepler space telescope to discover a class of extrasolar planets whose atmospheres have been stripped away.

According to the study, planets with gaseous atmospheres that lie very close to their host stars are bombarded by a torrent of high-energy radiation.

Due to their proximity to the star, the heat that the planets suffer means that their ‘envelopes’ have been blown away by intense radiation.

This violent ‘stripping’ occurs in planets that are made up of a rocky core with a gaseous outer layer.

The scientists used asteroseismology to characterise the stars and their planets to levels of accuracy not achieved before for these systems.

Asteroseismology is also known as stellar seismology and is the study of the internal structure of pulsating stars.

Earlier this year, experts discovered an exotic exoplanet called 55 Cancri e that is more than eight times the mass of Earth and has previously been dubbed the ‘diamond planet’ because models based on its mass and radius have led some astronomers to speculate that its interior is carbon-rich.

It uses the natural resonances of stars to reveal their properties and inner structures.

The results of the study have important implications for understanding how stellar systems, like our own solar system, and their planets, evolve over time and the crucial role played by the host star.

Dr Guy Davies, from the University of Birmingham’s School of Physics and Astronomy, said: ‘For these planets it is like standing next to a hairdryer turned up to its hottest setting.

‘There has been much theoretical speculation that such planets might be stripped of their atmospheres.

Astronomers detected wildly changing temperatures on this super Earth – the first time any atmospheric variability has been observed on a rocky planet outside the solar system – and believe it could be due to huge amounts of volcanic activity

The data for the study was obtained from Nasa’s Kepler spacecraft. Nasa is currently trying to resuscitate its planet-hunting spacecraft that has entered emergency mode 75 million miles from Earth. Pictured is an artist’s concept provided by Nasa shows the Kepler Spacecraft moving through space.

‘We now have the observational evidence to confirm this, which removes any lingering doubts over the theory.’

Dr Davies added: ‘Our results show that planets of a certain size that lie close to their stars are likely to have been much larger at the beginning of their lives.

‘Those planets will have looked very different.’

Scientists expect to discover and characterise many more of these ‘stripped systems’ using a new generation of satellites, including the Nasa Tess Mission which will be launched next year.

The findings are published in the journal Nature Communications.

Earlier this year, astronomers ‘sniffed’ the atmosphere of a distant super-Earth for the first time, and found it contained a highly poisonous form of hydrogen

The exotic exoplanet, 55 Cancri e, is more than eight times the mass of Earth and has previously been dubbed the ‘diamond planet’ because models based on its mass and radius have led some astronomers to speculate that its interior is carbon-rich.

Using new processing techniques on data from the Nasa/Esa Hubble Space Telescope, a University College Longon-led team of European researchers has been able to examine the atmosphere of 55 Cancri e in unprecedented detail.

They found evidence for hydrogen and helium in its atmosphere, but no water.