NASA expects upcoming space telescope to find 100,000 new worlds (earthsky.org)
Posted by Paul Scott Anderson in Space | May 6, 2021
NASA’s Roman space telescope mission – launching sometime in the mid-2020s – is expected to find at least 100,000 new exoplanets orbiting other stars, say astronomers.
Since the 1990s, astronomers have discovered more than 4,000 exoplanets – planets outside our solar system, orbiting other stars. NASA’s upcoming Roman Space Telescope – named for American astronomer Nancy Grace Roman – is one of the next generation of space telescopes that will play a big part in discovering more new worlds. In fact, NASA is expecting Roman, which is scheduled to launch in the mid-2020s, to discover upwards of 100,000 exoplanets, the space agency announced on March 31, 2021.
How will Roman do this? The telescope will use two different methods for detecting exoplanets, the transit method and microlensing. Most telescopes use primarily just one method, but by using two different ones, Roman – previously known as the Wide Field Infrared Survey Telescope (WFIRST) – will be one of the most prolific planet hunters ever launched.
Microlensing uses the gravitational light-bending effects of massive objects to detect planets orbiting a star. It does this by monitoring the tiny changes in light produced by the star. This happens when a more distant star happens to align with the closer foreground star, the one that is being studied for the presence of possible planets. The closer star acts as a sort of lens, bending the light coming from the further star. As the alignment changes slightly over days and weeks, due to the movement of the stars, the brightness of the more distant star changes slightly also. By looking at the pattern of changes in the light of the closer target star, astronomers can find clues as to there are any planets orbiting it.
This kind of microlensing event doesn’t happen often, however, so Roman will also search for planets using the most common technique, the transit method. As Ben Montet, a Scientia Lecturer at the University of New South Wales, said in a statement:
Microlensing events are rare and occur quickly, so you need to look at a lot of stars repeatedly and precisely measure brightness changes to detect them. Those are exactly the same things you need to do to find transiting planets, so by creating a robust microlensing survey, Roman will produce a nice transit survey as well.
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more: https://earthsky.org/space/nasa-roman-space-telescope-will-find-100000-new-exoplanets?
