There were only 125 binary asteroids that had been found and identified by the world’s astronomers. Last December, however, Andover’s Astronomy Research class discovered the 126th binary asteroid in a belt between Mars and Jupiter. Most asteroids in space are solitary, but binary asteroids are distinguished by a moon in their orbit. The astronomy class was originally monitoring asteroid van Woerkom 4296 when they discovered its moon.
“[The class does] a project where they’re trying to figure out the rotation period of an asteroid. They’ll choose an asteroid… and they’ll take pictures of it every night. Since the asteroid is not just a sphere, as it rotates, the sun reflects on it slightly differently. So they’re able to look and see how the brightness changes over a period of time. [A new group of students] picked the asteroid van Woerkom, and [when] they looked at the data… you find two different periods: one that is the actual asteroid and one which is the moon going around it,” said Ethan Brown ’17, a member of the astronomy class.
Van Woerkom’s moon’s diameter is approximately 30 percent the size of the asteroid itself. According to Caroline Odden, Instructor in Physics and Astronomy, finding a binary asteroid is exciting because of it’s rarity and how the asteroid itself has big enough mass to carry a moon.
Odden said, “This is the first binary asteroid we’ve discovered. We have discovered some other cool things, such as binary stars that the students have been able to record as discoveries. They’re also in the process of following up on some exoplanets, which is another kind of discovery. They’ve done lots of cool things, and some of those things are discoveries, but this particular one is new and different.”
“We’re lucky to have a telescope that has good enough resolution to pick up on the fact that there is a binary asteroid and also have access to the technology to make light curves. I think that [the discovery] also shows that we have talented students who work on the astronomy projects… When you’re doing astronomy research, you are actually making scientific discoveries,” said Paige Morss ’17, one of the students who discovered the binary asteroid.
Van Woerkom was officially registered as a binary asteroid in the Central Bureau for Astronomical Telegrams (CBAT) last January. The registration announces the discovery to the astronomy community. “The Minor Planet Bulletin,” an astronomy publication, will also release an issue on the details of the discovery and the specific light curves. All of the students involved in the discovery will be named on the paper.
Brown is currently taking his fifth term of astronomy research. He says that he is drawn to the class because of the potential discoveries that can occur when cataloging asteroids and looking at their data.
“The work that we do on the asteroid project is less groundbreaking, analytical research, and more that there’s so much out there and we just want to be able to catalog it all… This is just doing the hard work and cataloging them… So if someone [in the future] were to say that they wanted to do research specifically on binary asteroids, they have another one that they can include in their data… It’s extremely important for these discoveries to be made. The sheer number of asteroids makes it hard for all of them to be closely monitored and cataloged, so Andover’s contribution helps add to our knowledge of space as a whole,” said Brown.
Odden’s astronomy class will continue to catalogue and collect data on asteroids.
Odden said, “In astronomy, and in science in general, the goal is to extend knowledge and human understanding. This is just one piece in a very big puzzle, like a lot of discoveries are. There are some discoveries that are huge, and worthy of a Nobel Prize. But most of the time, there are many discoveries that together push science forward”