When astronomers use the Hubble space telescope to study deep space, the asteroids of our solar system may appear by surprise in the images, leaving their characteristic marks in galaxies or background nebulae. But far from being bothered by these stelae that cross what would otherwise be a “clean” image, astronomers take advantage of the fortuitous occasion to get more data on asteroids. Now they have captured a colossal photo of an asteroid crossing the Crab Nebula.
With that goal in mind, a team of ESA astronomers and software engineers started the Hubble Asteroid Hunter project last June, motivating volunteers from the public to help them find the trails of these objects in the large Hubble image archive. Through this initiative, more than 1900 volunteers have made more than 300,000 classifications in about 11,000 images in just a few months, far exceeding what the team of scientists expected.
One of the public enthusiasts was Melina Thévenot, from Germany, who when analyzing the space telescope’s data discovered the mark of an asteroid on the bottom of the Crab Nebula, in an image taken in 2005.
Inspired by the amazing cosmic scene, Melina decided to process the original image, combining several color filters to create the instant protagonist of this news.
The asteroid, which leaves its mark as if it were a “scratch” that crosses the image from the lower left to the upper right corner, is 2001 SE101, belonging to the main asteroid belt and discovered in a LINEAR survey in 2001.
The Crab Nebula, also known as Messier 1 or M1, was the first object recorded by the French astronomer Charles Messier in his famous catalog of deep-sky objects. This is the expanding remnant of the explosion of a supernova observed by astronomers in 1054 AD Apart from the cloud of gas and dust, the explosion left behind a neutron star in the center of the nebula – also visible in the image as the leftmost star of the two that appear in the center.
And while the possibility that a relatively close object – an asteroid – is aligned with a distant nebula is fascinating, it is not something completely unexpected either. In fact, the Crab Nebula, which has been observed by the Hubble about 300 times, lies casually near the elliptical – the orbital plane where most of the asteroids of the Solar System reside -, so it was only a matter of time before one crossed during one of the observations.
Now that volunteers have contributed to the platform to detect asteroid trails, astronomers will get to work. Knowing the date and time when Hubble took the images and thanks to the traces reflected in the photos, you can infer the positions and speeds of these celestial bodies. That is, the orbits and future trajectories of known or unknown asteroids can be determined to date with greater precision than before.
This knowledge is especially important for near-Earth objects (NEOs), since determining their precise orbits can help protect our planet from possible impacts.