Free Astronomy Magazine January-February 2021

45 JANUARY-FEBRUARY 2021 ASTRO PUBLISHING jectives an understanding of how re- current the configurations that in- clude both a rocky planet similar to the Earth (or a little more massive) and a gas giant as large as Jupiter are within the planetary systems of solar-type stars. For several years, scientists have sus- pected that, in our planetary system, Jupiter played an important role in maintaining life on our planet. Its presence beyond the so-called “snow line” would have prevented many asteroids and comets from traveling potentially dangerous or- bits, considerably reducing the num- ber of their catastrophic collisions with the Earth. It goes without say- ing that it would be interesting to understand if this combination of planets, orbiting solar-type stars, is purely coincidental or if it is instead a scenario common to a significant number of extrasolar systems. I n the background a super-Earth is represented, a planet more than twice the size of Earth, but which may still be habitable if it orbits in the temperate region of its star. [Amanda Smith] According to observations (which are limited in scope by various fac- tors), systems with a “cold Jupiter” quite far away from its star also quite often contain a super-Earth in