Last September darts mission For the first time, NASA has succeeded in deliberately changing the trajectory of an asteroid. This, of course, is very useful for future objects that pose a danger to the Earth. However, other groups of researchers took advantage of the situation for other purposes, such as study the composition of asteroids and at the same time get more information about the birth of our own planet.
They did this in two studies published today in Letters from an astrophysical journal. Both focus on using different instruments, but they are all focused on the same telescope: Very Large Telescope (VLT) European Southern Observatory (ESO). Thanks to the tools MUSE and FORS2 were able to measure very specific parameters of the dust cloud released by the DART impact and thus establish the composition Asteroid Dimorphos.
This, as we have seen, is very useful, because asteroids are one of the links in the chain that ends with the formation of new planets. Knowing what they are made of can help us understand how our own planet came into being. And for that, DART may have managed to kill two birds with one stone. You better not say.
Precise hit DART
When the DART mission was launched, it was for one main reason: to see if change the trajectory of the asteroid intentionally. For this, the asteroid Dimorphos was chosen, located 11 million kilometers from Earth. This distance was large enough not to affect our planet if something went wrong; but, at the same time, low enough that several telescopes, both space and ground, could fix it.
Among the space telescopes that captured the collision is the famous James Webb. But here, on Earth, there were also many who took it upon themselves to observe what was happening. One of them was VLT.whose tools were used to scrutinize what happened next.
MUSE and rainbow lights
To start, we used Multiunit Spectroscopic Viewer (MUSE) follow the debris cloud for a month. It is a very useful tool that combines research potential image processing device with measuring capabilities spectrograph. In addition, it takes advantage of the higher spatial resolution provided by adaptive optics.
The first thing that was noticed was that the dust cloud released after the DART impact was more bluish than an asteroid. This indicates that this cloud probably consisted of very small particles. In the following hours they formed new structures such as clumps, spirals and a long tail pushed by solar radiation. The swirls and tail were redder than the original cloud. Therefore, it is most likely that they consisted of larger particles.
In addition to all this, MUSE allowed the light of the cloud to be decomposed into rainbow pattern. Thus, its composition can be analyzed, since different elements absorb and reflect different wavelengths of the electromagnetic spectrum and have different colors.
How much has DART changed the asteroid’s surface?
The second tool used was FOcal Reducer / Low Dispersion Spectrograph 2 (FORS2). As explained on the ESO page, it has many benefits. First, it can display relatively large areas of the sky with very high sensitivity. In addition, it can take spectra of one, two or even several objects in the sky at the same time. But, above all, his great ability lies in the fact that he can measure light polarization. And that’s what was really helpful after the DART hit.
When we talk about the polarization of light, we mean that the waves oscillate in a certain direction. Measuring this is very useful because, as the lead author of the second study explained in a statement, Stefano Bagnulo“Tracking how the polarization changes with the orientation of the asteroid relative to us and the Sun reveals structure and composition of its surface“.
Thanks to FORS2, it was clear that the level of polarization dropped sharply after the DART impact. At the same time, the overall brightness of the system increased. The reason is not exactly known, but a possible explanation is that the impact was subjected to more ancient material from the interior of an asteroid. This hypothesis is due to the fact that the material inside the asteroid was less affected by the solar wind, which made it brighter and less polarized.
Although it is also possible that the impact destroyed particles on the surface, ejecting garbage cloud others are smaller.
What is clear is that both this study and the MUSE study by the astronomer’s team Cyriel Opitome, can tell us a lot about Dimorphos and, why not ?, about how the planets of the solar system were born. The data generated by the VLT will need to be further explored; because the impact of DART was much more than a rehearsal for a future Armageddon.
Source: Hiper Textual
