Asteroid Palmys May Be Hiding a Secret Twin. Help Us Find Out!

On July 28th, observers in North America have the chance to catch an asteroid as it occults, or passes in front of a distant star. But could this asteroid have a secret? Observations of 58931 Palmys last year hinted that this Trojan asteroid might have a hidden twin, making it not one, but two asteroids!

58931 Palmys is a fairly large asteroid, with an estimated diameter around 28 kilometers. It’s part of the Trojans, asteroids that follow Jupiter’s orbit around the Sun, and which date back to the dawn of the Solar System. But this asteroid may also have a gravitationally-bound companion that orbits along with it, meaning it would be a rare binary Trojan asteroid.

This July, Unistellar citizen astronomers can help get to the bottom of the mystery by training their eVscopes on 58931 Palmys during two back-to-back occultations sweeping across North America. One path cuts from Mexico through the midwestern U.S. and into Quebec, Canada, while the other is along the eastern coast of the U.S.

Asteroid passing in front of a star, known as an occultation

As of right now, there are three hypotheses about the asteroid. One is that 58931 Palmys has a previously-unknown twin. The second is that this asteroid simply has an odd shape, which could explain why it appeared to be two asteroids. Or, the observation from last year may simply have mistakenly appeared to show a double occultation. With the help of new observations, we should be able to solve the mystery.

Here’s how you can find 58931 Palmys on July 28th:

First, if it’s your first time doing an occultation, check out our general tutorial on finding occultations with your eVscope. If you’re already a seasoned shadow hunter, you can go straight to our Asteroid Occultation Predictions page, click on North America on the drop-down menu and scroll down the page until you find the two events about 58931 Palmys.

Visibiltity zone for the first event

Visibiltity zone for the second event

Select the event near your location and zoom into the map so you can see the exact locations where you can observe this occultation. Then check the information above the map to make sure you have the correct parameters (like the celestial coordinates and the telescope setting) and observe for the duration listed.

If you have any questions, please reach out to us at [email protected].