Making Simulated Main-belt Comets

Hello everyone!

I am Ishan, a summer student at ASIAA, Taiwan. I started working with the Comet Hunters team, about 3 weeks ago, on creating simulated Main-Belt Comet (MBC) images. Using appropriate mathematical functions, we are trying to create asteroid images with variable attributes like the direction of motion, brightness of tail and coma, etc. When ready, these images will be fed into the Comet Hunters website intermixed with the real images. How the project as a whole performs on these images will help us gain better insight into how well Comet Hunters can find different strengths of cometary activity and thus the true number of main-belt comets. For example, we can figure out up to what minimum brightness level of the coma (with respect to the nucleus) of the asteroid do the volunteers generally detect it.

For my present work, I am considering the nucleus to be just one pixel wide. For modelling the coma around it, we are using a 1/r profile centered around the nucleus. A sample coma is shown below.  Note that the actual coma will be much fainter than the nucleus.

As we can see, there is ‘cross’ visible at the center. This is due to the fact that we are plotting a circular function in square pixel-grid. Now when we trail this image in a randomly chosen direction, we get a weird output.

As you can see, there is a skewed ‘X’ at the center of the trail. To check whether the trailing function is faulty, I fed it with a simple 2D gaussian coma. The resultant image looks pretty decent!

We are currently trying to figure out the issue with the 1/r profile. Maybe using polar coordinates will resolve this. I will get back to you with the developments!

Cheers!