Finding Proxima b: the `planet hunters` searching for signs of alien life around nearby stars
    Source: Wired

After Pale Red Dot found Proxima b could have the conditions necessary to sustain life, the team plans to search for exoplanets around 15 other nearby stars

Astronomer Guillem Anglada-Escudé took four years to form the team that found Proxima b, the closest Earth-like planet to our solar system. Discovered in August 2016, it orbits the red dwarf star Proxima Centauri, 4.2 light years away.



It is slightly larger than Earth and has a temperature range that can accommodate liquid water. In short, it is the closest place to search for life in our nearby intergalactic neighbourhood. "The nearest stars and these red dwarfs, like Proxima, are the places where we have the chance to test these questions," says Anglada-Escudé, 37, a lecturer in astronomy at the Queen Mary University of London.



For years, scientists speculated that a planet lurked near Proxima Centauri, but they had no physical observation to back up the theory. Reams of spectrograph data showed that something was pulling Proxima Centauri back and forth, but nothing could reconcile violent flares with a planet`s orbit. The astronomers needed to untangle the star`s activity from the signal.



In 2012, Anglada-Escudé devised a way of analysing data to extract more accurate signals from spectrographs. This caught the attention of applied mathematicians at the University of Hertfordshire. Together, they developed a theoretical model of Proxima Centauri; all they needed was evidence to support it, as well as access to more historic data and telescopes on the ground.



So Anglada-Escudé and his colleagues set out to find Proxima Centauri enthusiasts around the world for a campaign they called Pale Red Dot. For 60 nights in 2016, the 31-person team obtained new data from the High Accuracy Radial Velocity Planet Searcher (Harps) spectrograph in Chile. They did this while simultaneously monitoring Proxima Centauri`s activity on a series of photometric telescopes. To their delight, the scientists clearly saw the planet`s orbital period in the signal. Thanks to the telescope observations, they could rule out interference from the star.



Next, Anglada-Escudé plans to mobilise more researchers to help search for exoplanets around 15 other nearby stars. "Within the next two or three years, we should be able to detect a lot of Proxima-like planets," he says. The search for life in the Universe will become more crowded.