How the next NASA exoplanet fighter could find more than 1,000 worlds • The Register

Les Boffins predict the success rate of telescope gravitational microlensing technology

In a galaxy not so far away … Our Milky Way, which will be probed by WFIRST

According to new estimates, NASA's developing wide-field infrared surveyor telescope could help scientists discover up to 1,400 distant exoplanets.

The mission, named WFIRST, was proposed in 2010 by the US National Research Council. Regarded as the successor of the Kepler Space Telescope in orbit at retirement, WFIRST will also be looking for exoplanets. He will also be able to locate exoplanets with larger orbits, thanks to the wonders of the gravitational lens.

Kepler ran out of gasoline at the end of October last year. He had discovered 2,681 exoplanets confirmed since its launch in the sky in 2009. He relied on the transit method to detect the presence of bodies in orbit around stars where, when the planets pass in front of their sun, they block a Part of the light from the oscilloscope sensors. By measuring diminished luminosity, scientists could estimate the size and mass of the planet.

The transit method is useful for searching for exoplanets whose orbital periods are close to the parent star and which transit quite often. The WFIRST satellite, however, will use the gravitational microlens. While the light of a distant star passes close to another star, considered the lens star, en route to Earth, the gravity of the star lens will bend the rays to give several images of the distant star.

If a planet hovers near the star lens, the gravity of it also inflects the light of the far star to create a third star image. This results in a temporary brightness that lasts only a few hours and only happens every few million years. WFIRST will scan a small parcel of space measuring about two square degrees to monitor 100 million stars in the center of our Milky Way galaxy to detect the presence of exoplanets using this technique.

"Although it's a small fraction of the sky, it's huge compared to what other space telescopes can do," said Matthew Penny, lead author of an article predicting WFIRST detection rates, published this week in The Astrophysical Journal.

"It's the unique combination of WFIRST – both a wide field of view and a high resolution – that makes it so powerful for microlens research around the world. Previous space telescopes, including Hubble and James Webb, had to choose one or the other. "

Scientists have spotted about 700 planetary systems containing more than one planet. Penny predicted that of the 1,600 new planets, about 100 could have the same mass or a lower mass than the Earth.

"WFIRST will allow us to find types of planets that we have not seen before. The WFIRST microfinance survey will teach us how often different types of planets are formed and how unique our solar system is, "added Penny, a postdoctoral researcher in the state's astronomy department. from Ohio to the United States.

NASA is still designing the space telescope and determining the appropriate equipment to use. The mission had a difficult start as plans were initially rejected, with the Trump Administration having limited NASA's budget last February. Fortunately, the decision was rescinded a month later, in March 2018, by Congress, which approved funding through the space agency to continue working on WFIRST. Its launch is planned for the mid-2020s. ®