Outreach

INAOE studies the physics of asteroids

• INAOE is working on the physical determination of these objects at its headquarters in Tonantzintla and Cananea.
• Knowing the physical properties of asteroids will allow us to prevent their collision with Earth or develop evacuation and damage mitigation programs.

Santa María Tonantzintla, Puebla, June 29, 2024. This Sunday, June 30, Asteroid Day is celebrated to remember the anniversary of the Tunguska impact in Siberia on June 30, 1908, and to raise awareness about the risks of these objects and the measures that can be taken at a global level in the event of an impact of one of these objects against our planet.

The National Institute of Astrophysics, Optics and Electronics (INAOE), a center coordinated by the National Council of Humanities, Sciences and Technologies (Conahcyt), is a founding member of the International Asteroid Warning Network, an alert network for monitoring asteroids, where the Institute contributes to the physical determination of asteroids.

INAOE conducts observations and develops scientific programs on these objects at its headquarters in Tonantzintla, Puebla, and at the Guillermo Haro Astrophysical Observatory in Cananea, Sonora, says Dr. José Ramón Valdés Parra, head ot the Astrophysics Department at INAOE.

In 2018, he adds, the Schmidt Camera in Tonantzintla was renovated to make professional observations since, for some years, due to light pollution, this historic telescope was used mainly for training students.

Thanks to these renovation works, the Schmidt Camera has become a telescope dedicated to the photometric observation of asteroids, that is, to the measurement of the sunlight reflected by these objects to determine some of their physical properties, such as their rotation period and its amplitude, which gives us a first idea of ​​their shape. “We create three-dimensional models of asteroids and we can also participate in astrometric measurements to determine the orbital parameters of the asteroids,” he says.

In Cananea, he adds, a spectrograph is used to obtain spectra of asteroids from different families of the main belt and of asteroids close to the Earth, with the objective of making the taxonomic classification to determine their surface mineral composition.

Valdés points out that these programs have been relevant for the students of the postgraduate program in Space Science and Technology of INAOE, one of whose research areas is the interplanetary environment.

Asked about the importance of these studies, Dr. Valdés Parra cited several reasons. One of them is that asteroids are the only objects in which the matter that led to the formation of the planets of the solar system more than 4,500 million years ago remains.

Another reason is of a more practical nature and has a high social content. It is known that asteroids close to Earth can enter into a collision orbit with us and we must be prepared to try to avoid this collision through some technologies.

One of them is the asteroid deflection technology, which seeks to modify their orbital speed: “We already know that we are not going to place a bomb with an explosive charge that destroys the asteroid because that does not modify the trajectory or its orbital speed. We have to find a technology that allows us to modify its orbital speed in order to avoid a coincidence in time, because there can be a coincidence in space because if at the moment when the asteroid is passing through the Earth's orbit, the Earth is on the other side of its orbit, nothing happens. The problem is when there is also a coincidence in time. That is why we have to modify the asteroid's speed and to find out if any of these techniques can be effective or not, we need to know their physical properties because a large asteroid is not the same as a small one, or if it is made of iron or stone."

Another technique that has already been tested is the kinetic impact, which is like playing billiards in space. A couple of years ago NASA sent the Dart mission to an asteroid, which crashed into the surface of a binary asteroid. This type of asteroid was chosen because it is very easy to detect if the satellite's orbit around the main asteroid is modified by the impact. The impact does not have an explosive charge.

“Dart transmitted its momentum to the satellite and, as it hit it in the opposite direction to the orbital motion, we expected the asteroid to slow down and this could be verified from Earth. The orbit of the satellite asteroid was modified with respect to the main asteroid,” adds Valdés.

A third technique is known as the “gravitational tractor”: “If we send a ship towards an asteroid and it does not hit it but becomes its satellite, we have a system that was previously a single body and now is a two-body system. In this new system, gravity plays its part and this modifies the asteroid’s orbital speed.”

Finally, laser ablation consists of placing a satellite around an asteroid with a very powerful laser that produces the ablation of the asteroid’s material, which will modify the asteroid’s mass and therefore its orbital speed.

However, if none of these techniques work and an asteroid impact is imminent, we need to create effective plans to mitigate damage on the Earth's surface "and for that we need to know the physical properties of the asteroid because the physics of the impact is well known and we could determine how much of the population in the impact zone would have to be evacuated."

Finally, another reason for studying asteroids is because the future of mining is in space, specifically in asteroids: "It is estimated that in 50 years the mineral resources that we have available for extraction will be exhausted and asteroids contain minerals."

To conclude, Dr. José Ramón Valdés invited everyone to the activities that, on the occasion of Asteroid Day, are being organized by INAOE at the Museum of Evolution in the Los Fuertes area of ​​the city of Puebla. The activities will take place on Sunday, June 30 from 12 to 6 p.m. There will be talks, demonstrations, workshops and an exhibition of meteorites.