Exoplanets are planets that exist outside of our solar system. The number of confirmed exoplanets is rapidly growing and now exceeds two thousand. An additional nearly 5,000 exoplanet candidates are awaiting confirmation in the NASA Exoplanet Archive. Most of these planets have been discovered by the NASA Kepler Mission, a space observatory launched by NASA specifically to discover Earth-size planets orbiting other stars. Smaller subsets of these planets are similar in size to the Earth and orbit in the (liquid water) Habitable Zones (HZ) of their host stars. It is estimated that about ten to fifteen percent of solar-type stars and about twenty to twenty-five percent of the more numerous cooler (red dwarf) stars host Earth-size HZ planets. These planets are of great interest because they have conditions roughly similar to Earth and therefore could be potentially habitable planets (PHPs).
In this talk, Dr. Edward Guinan, Professor of Astronomy and Astrophysics at Villanova University, Pennsylvania, briefly discusses how these exoplanets are discovered; however, the main focus will be on the stellar and planet properties that appear necessary for life to form and develop on their surfaces. New missions and techniques to detect signatures of life (bio-signatures) on these planets are presented along with the feasibility of interstellar missions to nearby HZ exoplanets that could support life.