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The principal investigator of the team that has discovered Próxima b is Spanish, Guillem Anglada-Escudé. He works in the astronomy unit at Queen Mary University (London).
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Proxima b orbits around Proxima Centauri, located 4 light years away.
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The entire experimental process was narrated in real time on Twitter, Facebook and on the Pale Red Dot blog.
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The project was sold to the ESO (European Southern Observatory), which is in charge of managing the telescopes with which Proxima b was finally discovered. In order for ESO to give the green light, the researchers advised to carry out dissemination tasks while the detection work was being carried out and it was emphasized that the search for an exoplanet in the star closest to Earth would be interesting for the public opinion.
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The main instrument used was the High Accuracy Radial velocity Planet Searcher (HARPS), a telescope (managed by ESO) oriented to the search for exoplanets by observing changes in radial velocity.
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The radial velocity method consists of measuring small changes in the emission frequency of the star as it moves – minimally – due to the influence of the planet that orbits around it. These changes in frequency (the Doppler effect) revealed that the star was moving only a few meters per second. The Pale Red Dot group also used a very efficient convolution method that allowed for a resolution in Proxima Centauri’s speed of movement unmatched to date.
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60 nights of observation were necessary but with only 2 weeks elapsed it was already perceived that the project was going to have a successful result. In fact, the entire nights were not used, but only a few minutes per night, which makes this project one of the most efficient in astrophysics.
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Two other observatories were used. One of them was not even for scientific use, but is intended for astronomical tourism.
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The project budget was € 0.
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Guillem Anglada-Escudé’s team was not the first to be interested in carrying out a similar experiment, but scientists from Queen Mary University were the first to present it in the right way and convince ESO to carry it out.
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Shortly after concluding the experiment, and before presenting the results in a collegiate way, there was a leak of the results by the newspaper Der Spiegel .
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Years in Proxima b are 11.2 days long. The planet always shows the same face to its star. This is called gravitational blocking or tidal coupling. This is due to the proximity of the planet to its star.
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To analyze the data obtained with the telescope, a novel system based on Bayesian statistics was used that allows us to see very small signals hidden in data streams.
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The existence of Proxima b has been suspected for 4 years, but until the scientific method has been applied in a forceful way, it has not been possible to reach a reliable result.
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In 2013, the team of researcher Anglada-Escudé sent a preliminary scientific article on Próxima b that was rejected by the journal that received it.
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Proxima b has a mass between 1.3 and 2.0 times the mass of Earth.
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Proxima Centauri is 12% of the mass of the Sun and 1,000 times weaker than it, but Proxima b is close enough that the energy received by the planet makes it stay in the habitable zone (it could host liquid water and, perhaps , lifetime.).
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Proxima b’s official name is Alpha Centauri Cb.
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The discovery of Proxima b has been a blow to the scientific community of exoplanets, since with very few means and resources, Pale Red Dot has achieved much more than other scientific groups against which it competes. In addition, the result is much more valuable since it implies having found a planet comparable to Earth at a distance reachable by humans.
Alberto Corbi is a professor at the Higher School of Engineering and Technology (ESIT) of the International University of La Rioja (UNIR ).
