NASA's Nancy Grace Roman Space Telescope will be able to unveil countless rogue planets based on new simulations. These exoplanets, unlike the ones in our solar system, are not tethered to a star and are freely floating bodies. Studying these planets will help us uncover the mystery behind how planetary systems are born, evolve, and die.
Planets beyond our solar system were discovered by astronomers in the 1990s. This knowledge made scientists realize that there could be more planets in our galaxy, they likely outnumber stars. A team of experts is seeking to find answers to this possibility and understand planet demographics by observing rogue planets.
"As our view of the universe has expanded, we've realized that our solar system may be unusual," said Samson Johnson, lead researcher of the paper published in the Astronomical Journal. "Roman will help us learn more about how we fit in the cosmic scheme of things by studying rogue planets."
The discoveries focus on the ability of the Roman Space Telescope to detect and classify remote planets. Astronomers have so far only tentatively identified some of these nomadic planets because they are too impossible to pinpoint.
Roman running a massive microlensing survey will discover rogue planets. Gravitational lensing is an optical phenomenon that exists when the presence of mass distorts the space-time fabric. The effect on very large objects, including black holes and whole galaxies, is significant. And isolated planets induce a measurable degree of warping, called microlensing.
When a stray planet aligns closely with a distant star from our point of view, the light of the star will bend as it moves around the planet through the bent space-time. The effect is that the planet functions as a natural magnifying glass that amplifies light from the star in the background. Scientists see the result as an increase in the brightness of the star when the star and planet align. Measuring how the spike varies over time gives hints to the mass of the rogue world.
Microlensing provides an effective way to scan rogue planets systematically, particularly those with low masses. These don't shine like stars and are instead very cool objects that emit too little heat for viewing infrared telescopes. Such vagabond planets are practically invisible, but due to their gravitational effects on the light of more distant stars, Roman will indirectly discover them.
Johnson and co-authors have shown that Roman can detect planets with masses as small as Mars. Studying these worlds can help to narrow down competing planetary formation models.
