It’s hard to be a young planet growing up with four parent-stars! The lucky eight major planets of our own Solar System orbit just one fiery Star–our Sun–but there are many exoplanets that have not been as fortunate. Some exoplanets–which are alien worlds circling distant stars beyond our Solar System–have been found dwelling within complex systems containing two or more stellar-parents. The world was made aware of the possible existence of such strange and exotic multiple star planetary systems back in 1977 with the fictitious planet Tatooine–when it made its debut in the first Star Wars movie–but for many years astronomers thought that such complex systems might not be able to form in the real Universe because they would be too unstable. However, they were wrong–and in March 2015, planet-hunting astronomers announced that they have come up with two new and important discoveries, the latest in a long series of detections of exoplanets with multiple stellar-parents: the first is a planet found to have three parent-stars, and the second is a planet with four–representing the second known case of a planet residing in a quadruple star system! The first quadruple-star-planet, KIC 4862625, was discovered in 2013 by citizen scientists using public data derived from NASA’s highly successful Kepler Space Telescope. 바카라사이트
Even though the second quadruple-star-planet was already known, it was originally believed to possess “only” a trio of stellar-parents–not four! The new findings can help planet-hunting astronomers understand how multiple star systems can influence the formation, development, and ultimate fate of their severely challenged planetary offspring.
The discoveries were made by astronomers using instruments fitted to telescopes at the Palomar Observatory in San Diego, California; the Robo-AO adaptive optics system, developed by the Inter-University Center for Astronomy and Astrophysics in India and the California Institute of Technology (Caltech) in Pasadena, California; and the PALM-3000 adaptive optics system, developed by NASA’s Jet Propulsion Laboratory (JPL) in Pasadena.
The Hunt For Planets With Multiple Stellar Parents
Back in 1977, astronomers had not yet detected alien worlds circling distant stars. The very first exoplanet in orbit around a Sun-like star was not discovered until 1995, but now the number of distant exoplanets detected by astronomers has skyrocketed –many, many more planets are now known to orbit distant stars beyond our own Solar System than the eight familiar worlds circling our Sun. Some astronomers even suggest that there are more planets than stars in our large barred-spiral Milky Way Galaxy. Exoplanets are known to exist in large numbers, and with great diversity–some are familiar-looking worlds that resemble planets in our own Solar System, while others are unlike anything astronomers once believed could exist. As of March 3, 2015, 1894 exoplanets had been discovered. The Kepler Space Telescope has also spotted a few thousand candidate exoplanets, most of which are expected to be validated. Kepler hunts for exoplanets using the transit method. This means that it searches for dips in a star’s brightness that may indicate planets are in orbit, blotting out a small amount of their parent-star’s brilliance. Many astronomers think that there is at least one planet on average orbiting each star inhabiting our Galaxy, and approximately 1 out of 5 Sun-like stars are thought to possess an “Earth-size” planet dwelling within what is termed its habitable zone. The habitable zone of a star is that “Goldilocks” region surrounding a stellar-parent where temperatures are just right for water to exist as a liquid–not too hot, not too cold, but just right! Where there is liquid water, there may also be life as we know it. However, at this point, Earth is the only planet known to be inhabited.
Astronomers have been on the hunt for planets orbiting stars beyond our own Sun for a very long time, and historically the search for exoplanets proved to be difficult. Detecting a planet the size of Jupiter, orbiting a distant star in our own Galaxy, has been compared to observing light bouncing of a mote of dust, close to a 1,000-watt light bulb, while the observer is miles away. Even stars that reside relatively close to our Solar System are very remote, and in visible light a distant exoplanet glows only in reflection. The closest star to our own Sun is actually a triple star system called Alpha Centauri, and it resides four light-years from our planet–or about 24 trillion miles!
The Dutch astronomer, mathematician, and physicist, Christiaan Huygens (1629-1695) was the first scientist known to attempt to hunt for exoplanets. Unfortunately, the next several centuries were riddled with one false alarm after another, and one disappointment following on the heels of yet another. It was not until 1988 that the first true and tantalizing indications emerged that triumph was fast-approaching. For example, Dr. Gordon A.H. Walker and his team at the University of British Columbia in Canada reported that they had observed hints of unseen planetary-mass bodies circling several “nearby” stars. These early discoveries were reported cautiously, however, with numerous disclaimers stating that orbiting planets were just one of many possible interpretations of the data.
Planetary scientists are in general agreement that it is not difficult for planets to be born circling a common star like our own Sun. As a dense blob of material within a giant, cold, dark interstellar molecular cloud, composed of gas and dust, collapses under its own weight to give birth to a new, seething-hot, and brilliantly glaring baby star, it also tends to leave behind a disk of dust motes circling the neonatal protostar. These particles are richly endowed with a natural stickiness, and they easily “glue” themselves together to eventually form larger and larger objects that merge together and finally grow to become full-fledged planets. For example, the birth and evolution of our own Solar System is thought to have commenced about 4.6 billion years ago with the gravitational collapse of a very small portion of a molecular cloud. Most of the collapsing mass collected at the center, forming our Sun, while the rest flattened out into a protoplanetary disk from which the familiar bodies of our Solar System formed–the planets, moons, asteroids, comets, and an assortment of smaller objects.