Different methods of searching for and finding distant exoplanets give different information about the planets found.
The transit method — where an exoplanets passed in front of its sun and dims the bright sunlight ever so slightly — gives astronomers not only a detection but also its radius or size.
The radial velocity method — where an exoplanet’s gravity causes its host star to “wobble” in a way that can be measured — provides different information about mass and orbit.
If a planet can be measured by both the transit and radial velocity methods, an important added dimension can be determined — how dense the planet might be. This tells us if the planet is rocky or gaseous, watery or even if it has a central core and might have an atmosphere. So many things have to go right that this kind of dual detection has seldom been accomplished for a relatively small and rocky planet, but such a new planet has now been found.
The planet, Gliese 486b, is a super-Earth orbiting its host star at only 24 light-years away. That makes the planet the third closest transiting exoplanet to Earth that is known, and the closest with a measured mass that transits a red dwarf star.
The authors of the study in the journal Science say Gliese 486b is an ideal candidate for learning how to best search for and characterize an all-important atmosphere, and to study potential habitability, too. Future telescopes will make this kind of work more of a reality.
“Gliese 486 b is not hot enough to be a lava world,” lead author Trifon Trifonov of the Max-Planck-Institut für Astronomie and colleagues write. “But its temperature of ~700 Kelvin (800 degrees Fahrenheit) makes it suitable for emission spectroscopy and …. studies in search of an atmosphere.”… Read more