The European Southern Observatory and the billionaire-backed Breakthrough Watch program say they have achieved first light with a new observing instrument designed to spot super-Earths in Alpha Centauri, the nearest star system to our own.
The NEAR instrument, which takes its name from the acronym for “Near Earths in the AlphaCen Region,” has been installed on an 8-meter (26.2-foot) telescope that’s part of ESO’s Very Large Telescope facility in Chile’s Atacama Desert.
NEAR takes advantage of a thermal-infrared coronagraph to block out most of the light coming from the stars in the Alpha Centauri system, a little more than 4 light-years away – including the sunlike stars Alpha Centauri A and B, plus a red dwarf called Proxima Centauri.
Cutting down on that glare makes it easier for an infrared imaging spectrometer known as VISIR to pick up the warm glow of planets orbiting the stars. The upgraded instrumentation, which took three years to develop, should be capable of detecting worlds down to twice the size of Earth.
Last month, ESO astronomers began a campaign aimed at taking in up to 100 hours’ worth of observations with NEAR, with support from the Breakthrough Watch program. Breakthrough Watch is one of several initiatives created by Israeli-Russian billionaire Yuri Milner with the aim of looking for evidence of planets and perhaps even life beyond our solar system.
The first-light campaign is due to conclude on Tuesday, and Pete Worden, executive director of the Breakthrough Initiatives, said NEAR is meeting expectations.
“It’s clear that we’re going to have sensitivity that’s an order of magnitude better than we had previously,” Worden told GeekWire.
Based on the data collected so far, there’s no evidence of planets bigger than Neptune in the Alpha Centauri system, Worden said. Further observations should produce higher-resolution results over the coming year, he said.
If NEAR picks up the thermal signature of planets in the Alpha Centauri system, scientists could make measurements to determine whether the temperatures on those planets allow for water to exist in liquid form. That’d be a hopeful sign for life.
Three years ago, astronomers reported detecting an Earth-sized planet in what’s thought to be Proxima Centauri’s habitable zone, although there have been nagging questions about just how habitable it is.
NEAR could reveal whether Alpha Centauri A and B have planets as well.
“NEAR is the first and (currently) only project that could directly image a habitable exoplanet,” Olivier Guyon, lead scientist for Breakthrough Watch, said today in a news release. “Fingers crossed – we are hoping a large habitable planet is orbiting Alpha Cen A or B.”
The coronagraph isn’t NEAR’s only innovation: The telescope was upgraded to take advantage of adaptive optics, a technology that compensates for the distortions caused by Earth’s atmospheres. ESO also uses chopping strategies to reduce data noise and allow for rapid switching between target stars.
“This is a valuable opportunity, as – in addition to its own science goals – the NEAR experiment is also a pathfinder for future planet-hunting instruments for the upcoming Extremely Large Telescope,” said Markus Kasper, ESO’s lead scientist for NEAR.
Worden said the NEAR project already has proven that valuable astronomy can be done at relatively low cost. “It was a pretty affordable thing – a few million dollars for the effort,” he said.
Data from NEAR’s observations will be publicly available from the ESO archive under program ID 2102.C-5011. Worden said that availability should provide opportunities for the astronomy community to contribute to the planet-hunting cause.
“Human beings are natural explorers,” Milner said in a statement. “It is time we found out what lies beyond the next valley. This telescope will let us gaze across.”
The NEAR instrument was built in collaboration with the University of Uppsala, the University of Liege, the California Institute of Technology and Kampf Telescope Optics. In addition to Breakthrough Watch, Milner supports Breakthrough Listen’s $100 million SETI campaign and the $100 million Breakthrough Starshot effort to send miniaturized probes through the Alpha Centauri system.