Astronomers Eye New ‘Invisible’ Stars Using One Key Principle Predicted by Einstein’s Theory of General Relativity
An international team of astronomers using three years of data from the European Space Agency's Gaia Observatory has discovered – and proven – that there is a brand-new binary star system hiding in the Cygnus constellation, according to a report from Science Alert.
One component of the Gaia Observatory scans the sky to record any aberrations and alert astronomers to all of the strange things that can happen in our night sky. A few years ago, that alarm finally went off on something called "Gaia16aye."
"We saw the star getting brighter and brighter and then, within one day, its brightness suddenly dropped," Łukasz Wyrzykowski, an astronomer at the University of Warsaw, Poland, provided the background speaking in an official statement from the ESA.
They immediately recognized that this was out of the ordinary. Wyrzykowski continued, "This was a very unusual behaviour. Hardly any type of supernova or other star does this."
To find out what could be causing this, the team relied on input from telescopes and observatories around the world, analyzing over 25,000 data points over three years.
It turns out, there was not just one star but two – and what they were witnessing confirmed the part of Einstein's theory of relativity that predicts gravitational lensing. This is what happens when light emitted from Point A is traveling to Point B over vast distance – and a third massive object, Point C, comes between the two. The gravitational pull of a third massive object (that comes between the source and the observer then distorts the light comes from Point A, and functions as a magnifying glass so that Point A appears temporarily magnified to Point B.
In this case, "the rotation was fast enough and the overall micro-lensing event slow enough that the background star entered the high magnification region, left it and then entered it again," noted Wyrzykowski.
The two small stars are roughly one-half and one-third the size of our Sun each, and separated by just twice the distance between Earth and Sun.
"We don't see this binary system at all, but from only seeing the effects that it created by acting as a lens on a background star, we were able to tell everything about it," explained Dr. Przemek Mróz, an astronomer at Caltech.
"We could determine the rotational period of the system, the masses of its components, their separation, the shape of their orbits – basically everything – without seeing the light of the binary components," Mróz continued.
A paper has been published in the journal Astronomy and Astrophysics.