The dream of directly visualizing planets like Earth outside of the solar system got a little closer with a new technique developed by an international group of astronomers. As a demonstration, they have used it to study the Alpha Centauri system (which is closest to us, 4.3 light-years from here) and may already have found a planet there.
The project, called NEAR (English acronym for New Lands in the Alfa Centauri region) involved installing updates for one of the VLT instruments, the Very Large Telescope, in Chile. The mid-infrared camera received a new coronograph that blocks the light of the imaginary stars and thus enables the observation of less bright objects in their surroundings. In addition, it was used in conjunction with one of the VLT telescopes with a malleable secondary mirror that compensates for image distortion caused by atmospheric turbulence in real time.
The researchers, led by Kevin Wagner of the University of Arizona, estimated that it would be possible to discover planets at the extreme limit up to three times the diameter of Earth around the habitable zone of the largest of the two main stars, Alfa Centauri A. , with 100 hours of observation.
It wouldn’t be a rocky planet like ours yet, but it’s getting closer. They estimate that with next-generation telescopes with a primary mirror of about 30 meters (as opposed to the VLT of 8 meters) it should be easy to see a planet like Earth in Alfa Centauri in just a few hours.
The system observation campaign was conducted between May and June 2019, and then researchers had to remove the noise generated by the telescope and its surroundings from the image (almost everything generates heat, i.e. infrared emission that contaminates the detection). That left a constant glow at a distance of 1.1 astronomical units from Star A, a planet between 3 and 11 times that of Earth. Something between a mini tune and a Jupiter. Only observations by other methods excluded a Jovian equivalent. So if it really is a planet, it will be smaller than Saturn.
Scientists also point out that in view of the novelty of the technology, it cannot be ruled out that the detection is an unforeseen image artifact. They went out of their way to get around this, even testing artificially inserting planets into the image to see if the processing caught on, and everything makes it look like it was real – a planet or maybe a disk of dust around the star. The only way to confirm the actual identity of the object from now on is to make new observations. However, there is no doubt that it is a promising first result that also paves the way for observing other nearby stars such as Epsilon Eridani, Epsilon Indi, and Tau Ceti. The results were published in Nature Communications.
This column is published in Folha Corrida on Mondays.
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