They found a 5.5 Earth mass extrasolar planet orbiting what seems to be a red dwarf star at around 2.6 AU, a distance that would put it between Mars and Jupiter's orbits if it was put into our system. The new planet and its star are about 20,000 light years away towards the center of the galaxy.
It was found with the gravitional microlensing method, which detects how the light is bent by a star between the planet's star and us. The planet is detected by its additional distorting of the light. This method can detect lower mass planets. They said that it suggests that lower mass planets may be more common than higher mass planets because if higher mass ones were more common, dozens of those would have been found.
The higher mass planets that had been found were found with a different method, the radial velocity method, that uses dopper shift of the star's light to see how the star orbits the barycenter of the system of its planets and itself.
Universe Today
CNET
Nature paper
Wikipedia
Discovery page
This page has a chart showing where the new planet is with its mass and distance from its star compared to those of other extrasolar planets. There are lots of high mass close planets because the radial velocity method is good at detecting those planets. They'll continuing monitoring for planets with the microlensing method to find more low mass planets.
It was found with the gravitional microlensing method, which detects how the light is bent by a star between the planet's star and us. The planet is detected by its additional distorting of the light. This method can detect lower mass planets. They said that it suggests that lower mass planets may be more common than higher mass planets because if higher mass ones were more common, dozens of those would have been found.
The higher mass planets that had been found were found with a different method, the radial velocity method, that uses dopper shift of the star's light to see how the star orbits the barycenter of the system of its planets and itself.
Universe Today
CNET
Nature paper
Wikipedia
Discovery page
This page has a chart showing where the new planet is with its mass and distance from its star compared to those of other extrasolar planets. There are lots of high mass close planets because the radial velocity method is good at detecting those planets. They'll continuing monitoring for planets with the microlensing method to find more low mass planets.
