Thousands of planets have been found by exoplanet hunters and most of them orbiting close to their host stars. But few rogue planets have been detected that float freely through the galaxy and they are not bound to any star. Many astronomers believe that these plants are common than people know. But the techniques used to find planets haven’t been up to the task of finding them.
A survey will be conducted by NASA’s Nancy Grace Roman Space Telescope to discover many more exoplanets. Powerful techniques will be used that are available to a wide-field telescope. The stars in the Milky Way Galaxy move, and chance alignments can help to find rogue planets. With a distant star, when a free-floating planet aligns, this can cause the star to brighten. The background star’s light is briefly magnified during such events as the planet’s gravity acts as a lens.
The distance to the lensing planet is not known properly. A mission concept is being developed by Goddard scientist Dr. Richard K. Barry called the Contemporaneous LEnsing Parallax and Autonomous TRansient Assay (CLEoPATRA). The purpose is to calculate these distances. Parallax is the apparent shift in the position of a foreground object as seen by observers in slightly different locations. In the 19th century, astronomers first established the distances to nearby stars using the same effect.
With microlensing, it works a little differently. The apparent alignment of the planet and distant background star dramatically depends on the observer’s position. At slightly different times two well-separated observers would witness the same microlensing. Each one will be equipped with a precise clock. The planet’s distance is determined by the time delay between the two detections.
CLEoPATRA would hitch a ride on a Mars-bound mission to maximize the parallax effect that launches around the same time. Around the Sun, it would place its orbit, achieving a sufficient distance from Earth to measure the microlensing parallax signal effectively. This will help to fill in the missing information.
From the principal observatory, CLEoPATRA would be at a great distance. The parallax signal should then permit the astronauts to calculate quite precise masses for these objects. Understanding these free-floating planets will help fill in some of the gaps in knowledge in how planets are formed. The astronauts are on a mission to find as many free-floating planets as they can find. Once they are found they will analyze their masses to find out which factors are common and which are not.
In early August CLEoPATRA completed a Mission Planning Laboratory study at Wallops Flight Facility to efficiently find these planets. It will use AI called RApid Machine learnEd Triage for the mission. The developed AI will help CLEoPATRA overcome a minimal data transmission rate. Millions of stars every hour or so will have to be matched by CLEoPATRA. There is no way to send all the data to Earth. Onboard the spacecraft will have to analyze the data. It will send back measurements for sources it detects during microlensing events.