The James Webb Space Telescope was used to confirm the existence of exoplanets for the first time. Known as LHS 475 b, this Earth-sized world is a cosmic stone-throwing distance and may be the first of many planetary discoveries by Webb.
More than 5,000 exoplanets (worlds orbiting stars other than the Sun) have been discovered to date, and thanks to James Webb’s more sensitive instruments, that number could skyrocket soon. To test its power, a team of astronomers pointed it at a star system where another telescope, NASA’s Transiting Exoplanet Survey Satellite (TESS), had previously found evidence of a planet.
TESS and many other instruments use what is called the transit method to detect exoplanets. Basically, if you look at a star for a long time, you’ll find that the brightness of its light diminishes. If these occur in a predictable pattern, it could indicate a planet passing in front of the star.
TESS implied this around LHS 475, but failed to confirm the planet’s existence, so the team trained Webb on the system. And as expected, we were able to confirm an exoplanet in just two transits, demonstrating its power.
Illustrations: NASA, ESA, CSA, L. Hastak (STScI); Science: K. Stevenson, J. Lustig-Yaeger, E. May (Johns Hopkins University Applied Physics Laboratory), G. Fu (Johns Hopkins University), S. Moran (University of Arizona)
This new world, named LHS 475 b, orbits a star in the constellation Octane just 41 light-years away. It revolves once every two days and appears to be 99% of Earth’s diameter. Although hidden very close to its primary star, it is a dim, cold red dwarf star that may orbit within its habitable zone.
However, don’t assume this is your lovely, comfortable Earth twin. LHS 475 b is much hotter, hundreds of degrees Celsius, and may have a pure carbon dioxide atmosphere or no atmosphere at all.
To investigate further, the scientists plan to take a closer look at the planet later this year with Webb to study the composition of its atmosphere. This is a big step towards the telescope’s goal of searching exoplanets for signs of life.
“These first observations from an Earth-sized rocky planet open the door to many future possibilities for studying rocky planet atmospheres with Webb,” said NASA’s Director of Astrophysics. As one Mark Crampin said, “Webb is bringing us closer to a new understanding of extrasolar, Earth-like worlds, and his mission is just beginning.”
The research was presented at a meeting of the American Astronomical Society on January 11th.
Source: NASA
