Active Asteroids

Frequently Asked Questions

In this section you will find a list of frequently asked questions (FAQ). This page will be updated as we get more questions and as the project evolves.

What exactly is Activity?

In solar system astronomy and planetary science, activity is a broad term that describes material -- like dust or gas -- leaving a body. Solar system bodies -- meaning comets, asteroids, Centaurs

What are Volatiles?

In astronomy and planetary science the term volatiles usually refers to substances that are liquid or gas at room temperature on the surface of Earth. In space these substances usually sublimate -- meaning they change from solid to gas, skipping the liquid phase -- similar to dry ice on Earth.

How do you get the pictures?

The team developed a comprehensive pipeline to extract the thumbnail images for this project. The process begins by examining the Dark Energy Camera (DECam) archive to see what data is available. We then figure out what objects may be in those images. We download individual images and perform a series of checks to make sure the object is really in the thumbnail and that it can actually be seen. We assess the overall content of our image repository and copy thumbnails we want to a cloud storage service and upload thumbnails to Zooniverse for classification. This is a highly oversimplified description of a very complex process, but you can read more in our publication "SAFARI: Searching Asteroids for Activity Revealing Indicators" discussed in the Results section.

Where do these pictures come from?

See also "How do you get the pictures?" above. The images primarily come from the Dark Energy Camera (DECam) instrument, with a few coming from the earlier Mosaic2 instrument, both mounted on the Blanco 4-meter telescope at the Cerro Tololo Inter-American Observatory (CTIO) in Chile.

What's the difference between an active asteroid and a main belt comet?

You may hear these terms used interchangeably, but strictly speaking main belt comets (MBCs) are a subset of active asteroids. MBCs orbit only within the main asteroid belt that is found between the orbits of Mars and Jupiter.

How do you know activity in an image is real?

This question is basically asking how we can tell if the activity in question is really coming from the object, and not an image artifact or some background object such as a galaxy. To evaluate potential activity we first consider how many images of the activity we have. If we only have one image of the activity, we may extract a "comparison field" that shows exactly the same field of view but at a different time. If the "activity" is still there but the asteroid is not, then the "activity" is actually something else, such as a background galaxy. Hopefully we have multiple images of the object being active. No matter what images we have, in the case of a new active object discovery we would carry out a follow-up observing campaign to study the object and confirm activity.

What will you do with the classifications?

We will carry out a follow-up observing campaign of newfound active objects in order to confirm activity and to study the object in more detail. Classifications may also be used to train machine learning systems and inform future ground- and space-based observatories about various aspects of finding and observing active objects.

Where is the research being conducted?

Northern Arizona University and Lowell Observatory are both located in Flagstaff, Arizona.

What kind of resources are necessary for this project?

Monsoon is the Northern Arizona University high performance computing cluster. The project pipeline can use up to 500 CPUs, 32 Tb of RAM, 100 Tb of local storage and 50 Tb of cloud storage.