Exoplanets orbiting alien suns could be stretched and pulled by the gravitational influence of their parent stars. Now, astronomers believe they may have found a method of detecting these distant worlds through a unique technique.
The first exoplanet was discovered in 1993, and over 1,800 other worlds have been spotted by astronomers since that time. Alien worlds of all different sizes have been found so far, orbiting at various distances from their local stars. The largest of the planets, so-called super-Jupiters, and those orbiting closest to their parent star are the easiest to detect. Worlds close to their suns are subject to tremendous heating, which can lead to scorching temperatures, as well as significant tidal forces, which can warp the shape of planets.
"Imagine taking a planet like the Earth or Mars, placing it near a cool red star and stretching it out. Analysing the new shape alone will tell us a lot about the otherwise impossible to see internal structure of the planet and how it changes over time," Prabal Saxena of George Mason University, said.
Red dwarf stars are significantly smaller and cooler than our own Sun, and are the most common variety of stellar bodies in the Universe. Saxena and his team examined exoplanets orbiting close to red dwarf stars. Because they are so close to their suns, they are gravitationally locked, causing one face of the planet to constantly face toward their stars, similar to the way the Moon revolves around the Earth.
This action warps the rocky body into an egg-like shape, with the pointy end eternally turned toward the local star. Alien worlds can often be detected when they orbit in front of their sun, blocking out a small portion of light from the star. Saxena believes rocky alien worlds, warped into egg-like shapes, may be detected through the distinctive pattern produced as the planet passes between its star and the Earth. Through observing these small worlds, astronomers may be able to learn more about smaller alien worlds. This could assist researchers studying how the Earth and terrestrial planets in our own solar system formed and developed over time.
Some of the most powerful telescopes in the world are able to detect rocky planets orbiting near their suns, and instruments coming online in the next few years, such as the James Webb telescope, could make observations more common.
Development of the new technique to detect planet warped by tidal forces from their local star was detailed in the journal Monthly Notices of the Royal Astronomical Society.