TRAPPIST-1 is no longer the exoplanet dream we once hoped
TRAPPIST-1, the star system 39 light years away that could hold the potential for Earth-like planets to exist, may not be all that great after all. Initial reports suggested that this nearby system could hold up to seven possibly habitable planets but new findings suggest TRAPPIST-1 is too old to sustain life.
Researchers originally believed the TRAPPIST-1 system was around 500 million years old due to its compact nature. Now though, it’s believed that the TRAPPIST-1 star is actually between 5.4 and 9.8 billion years old. This makes the TRAPPIST-1 system over twice as old as our Solar System – which was formed around 4.5 billion years ago.
“Our results really help constrain the evolution of the TRAPPIST-1 system, because the system has to have persisted for billions of years. This means the planets had to evolve together, otherwise, the system would have fallen apart long ago,” said Adam Burgasser, an astronomer at the University of California who worked on the research paper.
Because TRAPPIST-1 is now a lot older than previously thought, researchers have begun to question if it really is the holy grail of new planets that it was once thought to be. The TRAPPIST-1 star may be more stable than other dwarf stars, meaning that being closer to it isn’t as dangerous as first thought, but because of its age, it’s likely that the close-orbiting planets have been completely irradiated by long exposure to the star.
This radiation is most likely to have boiled off the atmosphere and a large amount of surface water. It’s thought that the equivalent of an ocean worth of water on Earth has been completely boiled away. The researchers liken TRAPPIST-1’s planets to Mars – a planet that likely had surface water but was boiled away over billions of years thanks to a thin atmosphere.
It certainly sounds like our chances of habitable planets in this galactic postcode have been dashed, but there is still a thin layer of hope. Because all the planets within the TRAPPIST-1 system have lower densities than Earth, it’s possible that water or other volatile molecules could produce thick atmospheres that can survive the battering that the TRAPPIST-1 star would have been unleashing onto the system. It’s also thought that a thick atmosphere could help distribute heat across the planet, meaning even the dark side of these tidally-locked planets would still receive warmth.
Conversely, this may have a greenhouse effect and produce a planet like Venus where its thick atmosphere has lead to it becoming uninhabitable.
“If there is life on these planets, I would speculate that it has to be hardy life because it has to be able to survive some potentially dire scenarios for billions of years,” Burgasser said.
The news around TRAPPIST-1 may be bleak, but thanks to these new discoveries we can understand how star systems are formed and move closer to understanding just how habitable planets come to life. In any case, don’t be too glum: you were always going to die on Earth anyway.