Astronomers at the New Zealand's University of Canterbury discovered a very rare super-Earth. The new planet that they've spotted is one of the very few extra-solar planets that have been detected with both sizes and orbits close to that of Earth.
A planet that has the same characteristics as Earth
According to the researchers, there are multitudes of Earth-like planets sprinkled throughout the Milky Way galaxy, but they are not so easy to find. Only around a third of the over 4,000 exoplanets found and confirmed are rocky and most of those discovered are within a few thousand light-years of Earth.
The extra-solar planet is another term for an exoplanet, which describes a planet that is located outside the solar system. There are only artists' impressions of what the planets might look like, but they continue to fuel the curiosity of the people.
The research was published in The Astronomical Journal, and it states that the newly spotted exoplanet's year lasts about 617 days and it travels around a much less massive star than the sun. It is located near the Milky Way's central bulge of stars. For comparison, Earth is about 25,000 light-years away from the galactic center.
How to detect exoplanets
Most of the exoplanets that are now known have been detected using one of two methods, the transit, and the wobble. The transit method detects planets based in the regular, minuscule dips in starlight when an exoplanet passes in front of it. The wobble method detects minuscule wobbling exerted on a star by the gravitational influence of an exoplanet.
However, there is a third method based on the predictions of general relativity, it is gravitational microlensing. It is like imagining two stars, one behind the other, and an observer at some distance again. The rays of light from the rear star are slightly bent by the gravity of the closer star as they pass by. This distorts and magnified that source light, hence the gravitational microlens.
When an exoplanet is thrown into the mix, it creates a further disturbance in the light that reaches the observer, that is how astronomers recognize that there is a planet. They can also analyze the light curve of the microlensing event to know the parameters of the system.
Is the planet exoplanet habitable?
The truth is, experts still do not know if the exoplanet could be habitable. They do not know the nature of the star yet because the temperature and activity level of a host star is vital in habitability. The star is also so far away that there are not instruments created that are sensitive enough to study its spectrum and to determine if it has an atmosphere.
One of the biggest questions about the Universe and the potential life outside Earth is how often it has the opportunity to arise. It can arise on rocky exoplanets since it did so here on Earth. So the more rocky exoplanets that are found, the better humans can understand that constraint.
What the research does demonstrate in all of this is the power of gravitational microlensing and how effective it is as a tool to find distant, low-mass exoplanets.