Summary: Astronomers have discovered a planetary free agent floating through the Milky Way, unbound to the gravity of any nearby stars. The discovery, detailed Thursday in Astrophysical Journal Letters, suggests the Milky Way may be teeming with rogue planets.
Original author and publication date: Brooks Hays – October 29, 2020
Futurizonte Editor’s Note: This is yet another indication of how little we know about what’s out there
From the article:
The new exoplanet, the smallest free-floating planet astronomers have found, is too small to be directly observed.
Researchers were able to spot the rogue world — which is somewhere between the size of Mars and Earth — with the assistance of a microlensing event.
“If a massive object — a star or a planet — passes between an Earth-based observer and a distant source star, its gravity may deflect and focus light from the source,” lead study author Przemek Mroz, a postdoctoral scholar at the California Institute of Technology, said in a news release. “The observer will measure a short brightening of the source star.”
“Chances of observing microlensing are extremely slim because three objects — source, lens, and observer — must be nearly perfectly aligned,” Mroz said. “If we observed only one source star, we would have to wait almost a million years to see the source being microlensed.”
To increase their odds of locating microlensing events, researchers rely on surveys. In this instance, astronomers utilized data collected by the OGLE survey, featuring a Chilean telescope and led by a team of astronomers at Warsaw University in Poland.
Every night, the OGLE survey’s 1.3-meter Warsaw Telescope scans the Milky Way center, home to hundreds of millions of stars, looking for changes in stellar brightness.