Night Sky Gaze
Planetary Collision

Planetary Collision Evidence Found in Space Debris

Astronomers have been wondering for over a decade about the origin of planetary dust seen in the orbit of binary star system BD +20 307. Some speculated that it could have been scattered throughout the system during a planetary collision event, a catastrophic and awesome display of raw cosmic energy.

Now, new data gathered from the Stratospheric Observatory for Infrared Astronomy (SOFIA) might shed some light on the history of this planetary dust.

Is it possible that system BD +20 307 was home to a collision of two rocky planets, not unlike the Inner Planets of our own Solar System?

System BD +20 307

Star system BD +20 307 was first imaged in 2004 by researchers on Maunuakea, Hawai‘i. They were using the Keck and Gemini North telescopes when they detected the system. The infrared imaging used is particularly sensitive to warm dust, which the system has plenty of. However, the stars in the system are at least one billion years old, meaning any dust from their formation should have cooled off long ago.

The warm dust present in the system pointed to a more recent event at a very large cosmic scale. Researchers made a reasonably guess: that two planets in the system collided, resulting in huge quantities of dust and planetary fragments scattering throughout the system.

The fragments, in turn, would be gravitationally attracted to one another, colliding and creating yet more dust. This is known as a collisional cascade, though such an event hasn’t been directly observed by humans.

SOFIA Findings Point Towards Collision

The SOFIA findings were published recently in a paper headed by Maggie Thompson of UC Santa Cruz. “Our recent SOFIA observations, taken about 10 years after Spitzer’s measurements, indicate that the brightness of the dust disk has increased by 10% in the last decade,” says Thompson. While it’s presently unclear what could account for this brightness, Thompson and her colleagues have a few theories.

The first is that the dust could be warming as it is drawn closer to the binary stars at the heart of the system, causing it to increase in brightness. Another theory holds that this observation could instead be detecting the presence of a higher concentration of dust than a decade ago, indicating that a collisional cascade could be ongoing in the system.

Either way, it seems likely that at some point in the past tens of thousands of years, two planetary bodies collided with incredible force in the BD +20 307 system. Hopefully, future findings will shed more light on the system and the origins of its mysterious dust clouds.

Cameron Norris