Solar systems are kinda like our families. Just like in a family scenario, some worlds leave home. Once they’ve left the gravitational hold of their Star, they’re pretty much fated to drift through interstellar space forever, unbound.
Astrophysicists call these wanderers “rogue planets,” and they’re getting better at finding them. A team of space scientists has found one of these drifting rogues that’s about the same mass as Mars or Earth recently.
Such planets are virtually impossible to see using traditional techniques because they do not orbit around a sun and cannot be spotted by the dimming they cause when passing in front of stars, and they do not give off any radiation.
Hence, the researchers use an astronomical phenomenon known as “gravitational microlensing” to spot such objects, which revealed themselves through the light of more distant stars.
The result was an effect that is much like a giant magnifying glass, which brightens light from a background “source” star to reveal the presence of the massive object.
Gravitational microlensing is only possible when an astronomer’s telescope lies in an almost perfect position with the observed object and the source star.
The newly-discovered planet, which has been named “OGLE-2016-BLG-1928,” was discovered in a micro-lensing event that only lasted only 41.5 minutes. That’s not much time for detailed data to be gathered.
Przemek Mroz, a postdoctoral scholar at the California Institute of Technology, said: “Chances of observing microlensing are extremely slim because three objects – source, lens, and observer – must be nearly perfectly aligned.”
“As in the case of other short timescale microlensing events, we cannot rule out the presence of a distant stellar companion,” they write. They were able to exclude any stellar companions out to a distance of only 8 AUs. But many planets orbit their stars at much greater distances than that. This planet was also found at the edge of current limits of detecting short-timescale microlensing events,”
“The source star is located in the red giant branch in the color-magnitude diagram, and some giants are known to produce stellar flares,”
“However, the properties of the event (its duration, amplitude, and light curve shape) do not match those of flaring stars.” He added.
Rogue planets have almost zero probability of hosting life, so they may never be the intense field of study in the same way that exoplanets have become. But they’re still intriguing, and like everything else, they hold clues to how nature works.
Researchers believe free-floating planets may have formed in the rotating discs of dense gas and dust around stars and were ejected from their parent planetary systems after gravitational interactions with other bodies.
They say studying these objects could help astrophysicists to learn more about the turbulent past of planetary systems such as the Solar System.