Astronomers have discovered a new exoplanet in a, particularly roundabout way. What makes it special is that it closely resembles Earth, but with expected stark differences. Scientists have since called the new discovery "one in a million."
The newly discovered Super-Earth is about four times our home planet's mass and orbits around a brown dwarf or a dim dwarf star. A year on the planet is about 617 Earth days, even though its orbit falls somewhere between those of our planet and Venus around our Sun.
But the team of astronomers that discovered the exoplanet didn't observe it directly. Instead, they spotted the planet because of how it and its star warped and magnified light, similar to a lens, which scientists call gravitational microlensing.
This method relies on the gravitational force of distant objects to bend and focus light coming from a star. As a planet passes in front of the star relative to the observer, the light dips measurably, which can then be used to determine the presence of a planet.
Gravitational microlensing is very uncommon, according to scientists from the University of Canterbury in New Zealand. In fact, only one in one million stars are being lensed at any given time. To spot the new Super-Earth, researchers had combined microlensing observations from two facilities: the Korean Microlensing Telescope Network; and Poland's Optical Gravitational Lensing Experiment.
Scientists can use the precise details of microlensing observations to calculate what acted as the lens, which more often than not, is a solitary star. But by analyzing the brightness of the target when it was microlensed versus when it wasn't, the research team found that the lens was actually a system, not a lone star.
The discovery was made possible by studying five days worth of data to isolate five hours of relevant observations, and then confirming that an instrument fluke wasn't to blame for the unusual finding.
The findings concluded with a description of the distant star system: a planet four times the mass of Earth and a star one-tenth the mass of the Sun. It's an incredibly rare Super-Earth, which orbits its star between the distances of Venus and Earth.
According to scientists, that combination is one of a kind because among the thousands of exoplanets astronomers have identified to date, such worlds in similar orbits are unique.
You can read the research in its entirety in a paper published in The Astronomical Journal.
