A “Halloween” asteroid that will pass close to Earth tomorrow could actually be a dead comet, according to research by Vishnu Reddy of the Planetary Science Institute.

On Halloween — Oct. 31 — asteroid 2015 TB145, considered a potentially hazardous object, will pass the Earth as close as 300,000 miles, or just 25 percent beyond the Moon’s orbit. Understanding the composition of these objects is important to understand how such threats might be mitigated, but also from where in the solar system they originated. The asteroid, 600 meters in diameter, poses no threat to Earth at this time.

On Oct. 30 Reddy, a PSI Research Scientist, captured the body’s spectrum and determined it to be similar to dark carbonaceous meteorites. Astronomers had suggested that the body could be a comet based on its orbit.

“We found that the object reflects about 6 percent of the light it receives from the Sun. That is similar to fresh asphalt, and here on Earth we think that is pretty dark, but it is brighter than a typical comet which reflects only 3 to 5 percent of the light,” said Reddy, who made his observations using the NASA Infrared Telescope Facility on Maunakea, Hawaii. “That suggests it could be cometary in origin — but as there is no coma evident, the conclusion is it is a dead comet.”

2015 TB145 presents a rare opportunity to study a potentially hazardous object up close. By knowing what it is made of, we can plan for future encounters with asteroids that pose a real threat.

Asteroid 2015 TB145 will safely fly by our planet on Halloween at 1:01 p.m. EDT (10:01 a.m. PDT).

PIO Contact:
Alan Fischer
PSI Public Information Officer
+1 520-382-0411, +1 520-622-6300

Science Contact:
Vishnu Reddy
PSI Research Scientist
+1 808-342-8932

Visit https://pbs.twimg.com/tweet_video/CSlokMgUwAAvnBR.mp4 to see a short video of the asteroid prepared using Arecibo Observatory radar images. Credit NAIC-Arecibo/NSF.

The project is funded by NASA Near-Earth Object Observations program.

The Planetary Science Institute is a private, nonprofit 501(c)(3) corporation dedicated to solar system exploration. It is headquartered in Tucson, Arizona, where it was founded in 1972. PSI scientists are involved in numerous NASA and international missions, the study of Mars and other planets, the Moon, asteroids, comets, interplanetary dust, impact physics, the origin of the solar system, extra-solar planet formation, dynamics, the rise of life, and other areas of research. They conduct fieldwork on all continents around the world. They also are actively involved in science education and public outreach through school programs, children’s books, popular science books and art. PSI scientists are based in 21 states and the District of Columbia, and work from various locations around the world.