Astronomers Find 3 Nearby Super-Earth Exoplanets in Newly Discovered Solar System
All things considered, the Earth is small—very small. Out of the thousands of exoplanets we've found over the past few years, only a small portion of them are rocky, Earth-sized planets. There are a number of planets called "super-Earths" that fall between Earth-sized and Neptune-sized, however, and astronomers just discovered a solar system with three.
The system is based around a star named GJ9827, which is only about 100 light years away and the three planets were discovered using the "transit method," which watches for dips in a star's brightness when an object (like a planet) passes in front of them. The transit method has become one of the main tools for spotting new exoplanets, but it's usefulness doesn't stop there:
"Astronomers can combine the transit light curves with velocity wobble observations to determine the planet's mass and radius, and thereby constrain its interior structure. The atmosphere can also be studied in a transit by using the fact that the chemical composition of the atmosphere means its opacity varies with wavelength. By measuring the depth of the transit at different wavelengths, it is possible to infer the composition and temperature of the planet's atmosphere."
The radii of the newly discovered super-Earths vary from 1.3 to 2.1 times that of the real Earth. That's an interesting range to be in, considering that planets at the larger end of the spectrum are more likely to be gaseous than rocky. Unfortunately for hopeful space colonists, these super-Earths are very, very hot—it's estimated that their temperatures are between 680 and 1182 degrees Fahrenheit.
Though these may not be the Earth-like planets we're looking for, their discovery means learning more about the galaxy's solar system, including the range of super-Earths floating around. If TRAPPIST-1 is any indication, there's a lot more promising solar systems out there.