Asteroid Gault

Hubble Space Telescope captured this image of asteroid Gault, showing two narrow, comet-like tails of dusty debris.

The UH Mānoa Institute for Astronomy (IfA) Asteroid Terrestrial-Impact Last Alert System (ATLAS) telescopes, located on Mauna Loa and Haleakalā, have recently found dramatic changes in an asteroid known as Gault.

Everyday, ATLAS observes thousands of asteroids located in the main asteroid belt. Gault, which was discovered in 1998, has shown signs of disintegrating as of January 2019. The asteroid was mistaken to be a new comet by Ken Smith, a collaborator with UH Mānoa from Belfast, Ireland, having a comet-like tail.

Scientists believe that long-term effects from the sunlight is what seems to be causing asteroids to slowly spin over time until they shed material. This event is predicted by astronomers to happen about once a year. ATLAS project scientist Larry Denneau and IfA colleague Robert Weryk took a look at UH Panoramic Survey Telescope and Rapid Response System telescopes after the new discovery and have found that Gault’s tail appeared in data leading back to December 2018.

Other astronomers from UH Mānoa, such as Jan Kleyna and Karen Meech, have discovered that NASA’s Hubble Space Telescope shows two narrow tails which have been slowly releasing material of the asteroid over these past few months.

When sunlight heats the asteroid, momentum from infrared radiation escaping the asteroids warmed surface creates the spinning process. If this force overcomes gravity, it becomes unstable and dust is sent into space.

Along with Gault, there is only one other asteroid known to have had a spin-up process known as a Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) torque.