The Southern European Observatory and the Breakthrough Watch program supported by billionaires say they have reached the first light with a new observation instrument designed to detect super-Earths in Alpha Centauri, the star system closest to ours.
The NEAR instrument, named after the acronym for Near Earth in the AlphaCen Region, was installed on an 8-meter telescope that is part of ESO's Very Large Telescope in the Atacama Desert in Chile.
NEAR takes advantage of a thermal infrared coronagraph to block most of the light coming from the stars in the Alpha Centauri system, just over 4 light-years away – including the Alpha-like stars Alpha Centauri A and B, a red dwarf named Proxima Centauri.
Cutting this brightness makes it easier for an infrared imaging spectrometer known as VISIR to capture the warm glow of planets orbiting the stars. Updated instrumentation, which took three years to develop, should be able to detect worlds up to twice the size of Earth.
Last month, ESO astronomers began a campaign to take up to 100 hours of observations with NEAR, with the support of the Breakthrough Watch program. Breakthrough Watch is one of a number of initiatives created by Russian billionaire Yuri Milner with the goal of searching for evidence of planets and perhaps even life beyond our solar system.
The first light campaign is due to be completed on Tuesday, and Pete Worden, chief executive of Breakthrough Initiatives, said NEAR is meeting expectations.
"It's clear that we will have a sensitivity that is an order of magnitude better than we had previously," Worden told GeekWire.
Based on data collected so far, there is no evidence of planets larger than Neptune in the Alpha Centauri system, Worden said. Other comments are expected to produce higher-resolution results next year, he said.
If NEAR gets the thermal signature of the planets in the Alpha Centauri system, scientists could take measurements to determine if temperatures on those planets allow water to exist in liquid form. That would be a sign of hope for life.
Three years ago, astronomers reported on the detection of an Earth-sized planet in what was thought to be the habitable zone of Proxima Centauri, although there were uncomfortable questions about how habitable it is.
NEAR can reveal whether Alpha Centauri A and B also have planets.
"NEAR is the first (and currently) only project that could directly project a habitable exoplanet," said Olivier Guyon, chief scientist at Breakthrough Watch, in a press release. "Fingers crossed – we're expecting a large habitable planet to be orbiting Alpha Cen A or B."
The coronagraph is not the only innovation of NEAR: the telescope has been enhanced to take advantage of adaptive optics, a technology that compensates for the distortions caused by the Earth's atmospheres. ESO also uses cutting strategies to reduce data noise and allow quick switching between target stars.
"This is a valuable opportunity because – in addition to its own scientific objectives – the NEAR experiment is also a path for future instruments to hunt the planet for the next Extremely Large Telescope," said Markus Kasper, ESO's chief scientist for NEAR.
Worden said the NEAR project has already proven that valuable astronomy can be done at a relatively low cost. "It was a pretty affordable thing – a few million dollars for the effort," he said.
Data from the NEAR observations will be publicly available in the ESO file under program ID 2102.C-5011. Worden said availability should provide opportunities for the astronomical community to contribute to the cause of the hunt for the planet.
"Humans are natural exploiters," Milner said in a statement. "It's time to find out what lies beyond the next valley. This telescope will allow us to look the other way.
The NEAR instrument was built in collaboration with the University of Uppsala, the University of Liege, the California Institute of Technology and the Kampf Telescope Optics. In addition to Breakthrough Watch, Milner supports the $ 100 million SETI campaign of Breakthrough Listen and Breakthrough Starshot's $ 100 million effort to ship miniaturized probes through the Alpha Centauri system.
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