Chapter 1: A Groundbreaking Discovery

A significant discovery has emerged from the Backyard Worlds: Planet 9 initiative, where citizen scientists identified a massive celestial body that may be classified as a brown dwarf. This object is located an astounding 1,600 astronomical units (AU) away from its host star.

During a recent Q&A session, we discussed the current trend in exoplanet discoveries, which seem to focus predominantly on the most bizarre and unusual findings. This trend arises from the fact that nearly 5,000 exoplanets have already been documented, leading to an overwhelming number of announcements that often go unnoticed. What once sparked excitement is now commonplace, with new findings typically involving planets that exhibit odd orbital patterns or unusual sizes, such as those that complete their orbits in less than a day or those comparable in size to Mars.

Today's announcement follows this pattern, as a new paper in The Astrophysical Journal elaborates on the discovery of this extraordinary exoplanet, possibly a brown dwarf, situated at an unprecedented distance from its star. To put this into perspective, 1,600 AU is 1,600 times the average distance from the Earth to the Sun. Discoveries of planets located at such vast distances from their stars are quite rare.

One of the most fascinating aspects of this discovery is that it was made by a volunteer citizen scientist participating in the Backyard Worlds: Planet 9 project. Jörg Schümann observed an object moving alongside a star, a finding that had been overlooked in previous searches due to the considerable distance separating the planet from its star. Lead author Jackie Faherty notes that this star had been examined by multiple teams searching for exoplanetary companions, but prior efforts focused too closely on the star itself. Thanks to the dedication of citizen scientists, an intriguing object was identified that many previous imaging surveys had not detected due to their limited range.

It's important to highlight that this initiative does not operate by analyzing light curves for transit signals as is common in many exoplanet studies. Instead, Backyard Worlds utilizes data from NASA's Wide-field Infrared Survey Explorer (WISE) mission, allowing citizen scientists to sift through digital images for objects that appear to shift between frames. These flagged objects then undergo further scrutiny.

So, what do we know about this newly discovered exoplanet? Its mass is estimated to be between ten to twenty times that of Jupiter, which is particularly noteworthy as the threshold for classifying an object as a brown dwarf is around thirteen times Jupiter's mass. Thus, it could either be an exceptionally large gas giant or a brown dwarf. The determining factor between the two classifications hinges on understanding how the object formed: planets develop from materials accumulating in protoplanetary disks, while brown dwarfs emerge from the gravitational collapse of massive gas clouds. Unfortunately, we currently lack sufficient data to reach a definitive conclusion, so we can simply acknowledge that there exists a remarkably massive celestial entity out there.