An Astronomical Event: Colliding Planets
The concept of two planets colliding might sound like an intriguing plot for a Star Trek episode, but it is more fact than fiction. Indeed, such an event has occurred around the star ASASSN-21qj, a conclusion researchers have arrived at including through social media.
Mystery and Discovery
The star ASASSN-21qj provoked frustration among astronomers when its brightness inexplicably diminished a few years ago. A perplexing phenomenon given there was no previous fluctuation in its brightness recorded. Astronomer Matthew Kenworthy was determined to unravel this cosmic mystery and committed to rigorous observation of the star. The breakthrough, however, came not from mere observation but a tip-off via social media. Another astronomer informed Kenworthy that the star’s brightness on infrared wavelengths had doubled three years prior. It was a revelation that took a surprised Kenworthy by storm.
The Mystery Unraveled
Armed with this new information, Kenworthy along with his team eventually solved the puzzle. They revealed in this week’s edition of Nature that the increase in infrared brightness followed by a decrease in visible light brightness were the results of a collision between two gigantic ice planets orbiting around ASASSN-21qj.
A Tale of Two Giant Ice Planets
Here’s what happened: two large ice giants were orbiting ASASSN-21qj when they collided. The collision generated an infrared (heat) glow, giving the impression that the star’s brightness had increased in infrared wavelengths. Additionally, an expanding debris cloud was created which, observed from Earth, seemed to pass in front of the star, causing an apparent decrease in the star’s brightness in visible light three years later.
Calculations and Models
A conclusion about the collision between these two large ice giants was derived from the noted infrared glow – spotted on social media and observed by the American NEOWISE mission, as researcher Simon Lock explains. The size, temperature of the glowing material, and duration of the glow, corresponded with the collision of two ice giants, deduced from their calculations and computer models. “What’s notable is that we believe this to be the first time we have seen the glow arising from a planetary collision,” adds researcher Grant Kennedy.
Implications and Future Studies
The researchers are enthusiastic about their findings and eagerly anticipate future observations. “It’s really a fantastic opportunity to learn more about what lies inside giant planets,” says researcher Ludmila Carone. Normally, the innards of such planets are hidden beneath a thick layer of hydrogen and helium atmosphere. But this collision catapulted material from the deeply concealed cores of ice giants, or deposited it in the outer regions of bodies formed by planetary collisions. This makes studying and observing these materials considerably easier.
