Stars are gravitationally fastened to their galaxies and move in concert with their surroundings. But sometimes, something breaks the bond. If a star gets too close to a supermassive black hole, for example, the black hole can expel it out into space as a rogue star.
What would happen to Earth if one of these stellar interlopers got too close?
What do UX Tauri, RW Aurigae, AS 205, Z CMajoris, and FU Orionis have in common? They’re young stellar systems with disks where planets could form. It appears those disks were disturbed by stellar flybys or other close encounters in the recent past. Astronomers want to know: did those events disrupt planet formation in the disks? What do they do? Does this happen in other systems? And, did our own solar system experience a strange encounter in its youth?
What causes an otherwise unremarkable star to become over 100 times brighter? That’s a question astronomers have been pondering since 1936, when a star in Orion brightened from 16th magnitude to 8th magnitude in a single year.
The star, named FU Ori, is still bright to this day. Astronomers have come up with different explanations for the star’s brightening, but none of them provides a complete explanation.
Within the Milky Way, there are an estimated 200 to 400 billion stars, all of which orbit around the center of our galaxy in a coordinated cosmic dance. As they orbit, stars in the galactic disk (where our Sun is located) periodically shuffle about and get closer to one another. At times, this can have a drastic effect on the star that experience a close encounter, disrupting their systems and causing planets to be ejected.
Knowing when stars will make a close encounter with our Solar System, and how it might shake-up objects within it, is therefore a concern to astronomers. Using data collected by the Gaia Observatory, two researchers with the Russian Academy of Sciences (RAS) determined that a handful of stars will be making close passes by our Solar System in the future, one of which will stray pretty close!
Next time you want to be the life of the party—if you’re hanging out with cool nerds that is—just drop that phrase into the conversation. And when they look at you quizzically, just say that’s the eventual fate of the Solar System.
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At the center of our galaxy resides the Galactic Bulge, a densely-packed region of stars, dust, and gas. Within this massive structure, which spans thousands of light-years, there are an estimated 10 billion stars, most of which are old red giant stars. Because of this density, astronomers have often wondered if a galactic bulge is a likely place to find stars with habitable planets orbiting them.
Essentially, stars that are closely packed together are more likely to experience close encounters with other stars, which can be catastrophic for any planets that orbit them. According to a new study from Columbia University’s Cool Worlds Lab, most stars in the Bulge will experience dozens of close encounters over the course of a billion years, which could have significant implications for long-term habitability in this region.