Astronomers have made an announcement about what they are calling one of their most significant discoveries to date in their hunt for other planets – a hot twin to our own Venus. The rocky planet, given the name GJ 1132b is similar in size to our neighbour and orbits a star some 39 light years away.
This means it is close enough to be examined by the next generation of telescopes that are currently being developed. These telescopes will be able to tell if the planets have atmosphere, something that so far has only been possible with the very largest planets discovered.
Researchers are very keen to be able to do this because such tests are the best opportunity to establish if there is life outside our Solar System.
Distant cousin
GJ 1132b is some 370 trillion kilometres away so it is unlikely that we will ever be visiting it with a spacecraft. But if the telescopes are able to identify the molecules that make up the planet’s air, this could be very revealing about what happens on the surface.
In reality, the planet has a low habitability index. It sits near to its star that the ‘year’ lasts only 1.6 Earth days meaning the planet is effectively ‘oven roasted’ according to one scientist. The results of its proximity to the star means that any water present would have boiled away long ago but there is still the chance of atmosphere.
This all makes the planet much more a cousin to Venus than to Earth, although Venus still only received one 15th of the heat of GJ 1132b – Venus is hot but not that hot.
Even with its poor prospects for life, studying the planet would be a useful testbed for observing other planets with more friendly features.
Atmospheric studies
Atmospheric studies of another planet isn’t an easy job and is done by probing the light from the star when the planet passes in front of it from the viewpoint of Earth. When this happens, the molecules in the air will leave their chemical footprint on that light.
Up until now, most of the planets we have discovered have been too far away to do this with the current telescopes we have. This means that only really large planets such as Neptune-sized or bigger have been able to tell us their story.
But these huge planets are generally less interesting than small rocky planets, where more gases are liable to be found that are relevant to life.
One element that makes studying the planet easier is that its host star is a red dwarf. This means it is both smaller and cooler than our Sun and also dimmer. These stars are some 10 times more common in the galaxy than our Sun’s type of star. This means that their planets are top candidates for further study because there are so many of them.
The new telescopes needed to conduct these studies aren’t too far away from operation. Super observatories that have mirrors some 40 metres across are due to be in use in the next decade. But before that, the successor to the Hubble Space Telescope will be operating. Known as the James Webb Space Telescope, it will launch in 2018 and is often referred to as a ‘planet-chasing machine’.
