Scientists have discovered a new planet with the mass of Earth, orbiting its star at the same distance that we orbit our sun.
The planet is likely far too cold to be habitable for life as we know it, however, because its star is so faint.
But the discovery adds to scientists' understanding of the types of planetary systems that exist beyond our own.
This 'iceball' planet is the lowest-mass planet ever found through microlensing.
The newly discovered planet, called OGLE-2016-BLG-1195Lb, aids scientists in their quest to figure out the distribution of planets in our galaxy.
An open question is whether there is a difference in the frequency of planets in the Milky Way's central bulge compared to its disk, the pancake-like region surrounding the bulge.
OGLE-2016-BLG-1195Lb is located in the disk, as are two planets previously detected through microlensing by NASA's Spitzer Space Telescope.
For the new study, researchers were alerted to the initial microlensing event by the ground-based Optical Gravitational Lensing Experiment (OGLE) survey, managed by the University of Warsaw in Poland.
KMTNet consists of three wide-field telescopes: one in Chile, one in Australia, and one in South Africa.
Although OGLE-2016-BLG-1195Lb is about the same mass as Earth, and the same distance from its host star as our planet is from our sun, the similarities may end there.
OGLE-2016-BLG-1195Lb is nearly 13,000 light-years away and orbits a star so small, scientists aren't sure if it's a star at all.
Alternatively, it could be a brown dwarf or ultra-cool dwarf star much like TRAPPIST-1, which Spitzer and ground-based telescopes recently revealed to host seven Earth-size planet
Ground-based telescopes available today are not able to find smaller planets than this one using the microlensing method.
A highly sensitive space telescope would be needed to spot smaller bodies in microlensing events.
NASA's upcoming Wide Field Infrared Survey Telescope (WFIRST), planned for launch in the mid-2020s, will have this capability.
What is Microlensing?- Microlensing is a technique that encourages the discovery of distant objects by using background stars as flashlights.
- When a star crosses accurately in front of a bright star in the background, the gravity of the foreground star focuses the light of the background star, making it appear brighter.
- A planet orbiting the foreground object may lead to an additional blip in the star’s brightness. In this case, the blip only lasted a few hours.
- This technique has discovered the most distant known exoplanets from Earth, and can detect low-mass planets that are substantially farther from their stars than Earth is from our sun.
