Are Mars’ Trojan Asteroids Pieces of the Red Planet?

By Jesse Emspak,

mars trojan

A mosaic of the Valles Marineris hemisphere of Mars. This view is similar to what one would see from a spacecraft, according to NASA.
Credit: NASA/JPL-Caltech

The Trojan asteroids that follow Mars in its orbit might have come from the planet itself, blown off in an ancient impact rather than being late arrivals, a new study suggests.

Several planets in Earth’s solar system have Trojan asteroids — bodies that run ahead of or behind the planet. Jupiter, for example, has thousands. Earth has at least one, discovered in 2010. Uranus, Neptune and Venus also have them. Trojan asteroids are so called because the first ones to be discovered were named for figures from the Trojan War, including Achilles and Agamemnon. NASA plans to launch a mission in 2021, called Lucy, to study six of Jupiter’s Trojan asteroids.

David Polishook, a researcher at the Weizmann Institute in Israel and lead author on the new study, posits that the Trojans following Mars were blasted off the surface of the young planet at least a billion years ago, and settled into their current positions soon after that.

Trojans orbit at Lagrange points, regions of gravitational stability numbered 1 through 5, where an object that is a small fraction of the mass of a planet and the sun, such as an asteroid, will maintain its position.

Around Mars, for example, Lagrange point No. 1 (or L1) is on an imaginary line connecting Mars and the sun, while L2 is directly behind the planet if one extends that same line. Extend the line through the sun so that it touches the point in Mars’ orbit exactly opposite the planet to reach L3. L4 and L5 are at points 60 degrees ahead and behind Mars along its orbit. (If you draw lines between L4, L5, Mars and the sun, you get two equilateral triangles.) Mars’ Trojan asteroids are at L4 and L5.

Mars has nine Trojan asteroids, the study notes. One, called 1999 UJ7, runs ahead of the planet at the L4 position. Three others, 5261 Eureka, 2001 DH47 and 2007 NS2, travel behind at L5. Astronomers had already studied the reflected light from Eureka and noted that the object was rich in the mineral olivine.

The new study shows that 2001 DH47 and 2007 NS2 also are rich in olivine. Olivine is rare in asteroids, but it is common in larger bodies — and occurs on Mars in impact basins.

mars trojan

An artist’s concept of NASA’s Lucy mission, which will study Jupiter’s Trojan asteroids.
Credit: Southwest Research Institute

“This mineral crystallizes in high pressure, for example in the mantle of terrestrial planets,” Polishook told, “Mars, Earth and Venus have olivine, too, but dynamically speaking, it is much easier for Mars to capture Martian ejecta than to capture Earth, lunar or Venus ejecta.”

That, Polishook told, is one good reason to think that the Trojans were pieces of Mars. Earlier studies estimated the age of Eureka is about 1 billion years, so that means the cluster of Trojans has to be at least that old.

The question, though, is how such large pieces of Mars settled into the Trojan orbit at the L4 and L5 points. Polishook thinks it happened because Mars and Jupiter — the latter, especially — have both migrated from the positions they were in when they formed.

Mars’ orbit, like many of the planets, changed in the early solar system. As this change progressed, bits of the planet that blasted off in an impact, which might ordinarily have escaped or remained in orbit around the planet itself, ended up as Trojan asteroids, Polishook said. “If ejecta are present within a new orbit of Mars, then they may be captured into a Trojan orbit.”

The Trojans could be captured this way only early in the solar system’s history — once the planets settled into their current positions, any bodies that ended up in Trojan orbits would tend to stay there, and any subsequent planetary migrations would free existing Trojans, Polishook said.

The study appears in Monday’s (July 17) issue of the journal Nature Astronomy.


Original article here.

NEOShield-2 participates in EUCASS 2017

eucass 2017 elecnor deimosThe European Conference for Aeronautics and Space Sciences (EUCASS) is the main continental scientific event for aeronautics and space, second only to the AIAA Scitech in the USA. The Eucass association was created by a group of european scientists in order to provide, on the old continent, a high quality forum for the aerospace scientific community. Eucass is member of Ecaero group, supported by the European commission, with Eccomas, Euromech, Ercoftac, Euroturbo and Ceas.

EUCASS is the natural high-level forum for all aeronautics and space research players. It showcases promising fundamental breakthroughs, enabling sciences and technologies. The main objectives are to:

  1. review the state of the art in Aeronautics and Space Sciences, focusing on promising innovations;
  2. promote industrial understanding of recent scientific breakthroughs and develop synergies between Aeronautics and Space, Academia and Industry;
  3. give Agencies and Industry the opportunity to present their programs, particularly EU’s Framework programmes.
eucass 2017 elecnor deimos

Miguel Hagenfeldt delivering his presentation

This years’ conference was the seventh issue and it took place in Milan, Italy, on 3-6 July. About 600 participants, of which 149 students, have attended and contributed to making it a very warm and lively forum. The number of papers received reached a total of about 700, of which 550 were presented either orally or in poster format. There were 34 countries represented.

The NEOShield-2 project was represented by its consortium member Elecnor Deimos, who presented the work achievements of WP5 (Reconnaissance S/C technologies).

The Reconnaissance GNC/AOCS technologies were presented in the Flight Dynamics, GNC and Avionics symposium, on Thursday 6 July, with oral presentation by Miguel Hagenfeldt of the paper entitled “Autonomous GNC/IP for Approach and Hovering of irregular small bodies”, on behalf of the Elecnor Deimos WP5 Team.



NEOShield-2 Agent Spain – Asteroid Day 2017

By Maksym Abramov, NEOShield-2 Agent in Spain

On the 30th June 2017, I organized a workshop about NEOs, Meteoroids, Asteroids, and Comets. It was to commemorate Asteroid Day and it was about past impact events, the threat from space and our answer to that threat. The event took place at the Avanza Educational Center in Granada, in Spain and target students from all courses.

Asteroid Day 2017 Agent Spain

First part

The workshop was divided in two parts. After a brief introduction, the first part got started, where I talked about mass extinction events on Earth in the past based on historical registers, such as the crater Chicxulub, and about the Chelyabinsk event, which have better coverage because of the amount of data that actually exists for our disposal thanks to recently expeditions to that places. I also talked about impact craters, how to distinguish them from volcanic craters, how they appear and what shapes and types exist, as well as their structure.

Group activity

Closing the first part, it was offered a brief in group activity supported by Deimos (NEOShield-2 project member), who prepared a set of images from their satellite database. There were two groups of pictures – one with real impacts craters and other with volcanic craters and geological structures which appeared as craters. The participants were asked to find the real impact craters. It was a funny activity, people were intrigued and I received very positive feedback.

Second part

In this part I explained which initiatives and programs we as community (UNOOSA) elaborate to protect the Earth and what the NEOShield-2 project does for that common mission. I talked about strategies and the different techniques of mitigation measures associated to asteroids and comets threat. I also explained the purpose, differentiation and value of NEOTωIST as an necessary and important space demo mission to acquire more knowledge and scientific data about asteroids and how we can defend our planet from possible hazardous NEAs.

Asteroid Day 2017 Agent Spain

Later on, I briefly talked about the space missions to asteroids and comets in the past and present. I also talked about the near future of space exploration and exploitation of resources, which could be contained within hundreds of asteroids already identified as potentially rich in high value metals or indeed in the thousands of asteroids in existence whose composition has yet to be confirmed.

And for the end of the workshop, we made a brief excursion on culture background and the participants could see asteroids in literature, movies, and videogames. I delivered some pins, stickers, cards, and flyers from the NEOShield-2 project and people were gladly surprised.

In sum, people liked the new information they received and I liked this experience which I never had before. I am looking forward to my next workshops!


NEOShield-2 Note:

The NEOShield-2 team is very glad to have Maksym on board and very proud of his effort and commitment to the cause. We are looking forward to his future events in Spain.

NEOShield-2 Agent Malta – Asteroid Day 2017

By Alexei Pace, NEOShield-2 Agent in Malta

A public event was held in Malta in the run up to Asteroid Day on 30 June 2017. The event was held at a recently restored seventeenth-century farmhouse at Buskett Woodlands in Siġġiewi (Malta).

The event was well-attended by members of the Astronomical Society of Malta as well as space enthusiasts as well as several foreigners who attended to learn more about the threat of an impact to the Earth from Near-Earth Asteroids (NEOs).

Some of those attending were skeptical at the thought of an asteroid hitting the Earth, thinking that this was only the subject matter of science fiction films. However they quickly changed their opinion once the opening video showing a collection of actual footage of the Chelyabinsk fireball was shown. This event has raised a lot of awareness since it happened so recently and it was captured and shared widely online on the social media.

My presentation commenced with a brief overview of how the solar system was formed from a large protoplanetary disk/s, explaining the roles of collisions in the early solar system as necessary for the formation of planets (collisional accretion) whilst in the late stages it causes collisional disruption. Asteroids and comets are the small bodies of the solar system, remnants and left over blocks from its formation.

Malta Agent Asteroid Day

Since these small bodies are the building blocks of the solar system, by studying asteroids one can even obtain a good insight of the constituents of the planets.

The Main Belt of the asteroids was then explained as well as the location of NEOs. Those attending were shown images of asteroids shot by amateur astronomers, appearing as points of light identical to the stars. Blinking of the images and stacking is used to track their motion and identify their nature. Imagery from space probes nowadays helps to reveal the true nature of asteroid surfaces and geology.

The first asteroid, Ceres, was discovered by Giuseppe Piazzi in Palermo on 1 January 1801. Piazzi is of significance in Malta since he taught mathematics there between 1770 and 1773.

Malta Agent Asteroid Day

A plot of asteroid impacts was shown to contain a lot of large impacts, much more than one could imagine. The 2002 Eastern Mediterranean Event is of significance as it happened so close to Malta. Luckily the object disintegrated over the sea and there was no ground impact. Other events described were the Tunguska one, as well as the one in the Yucatan peninsula (65 million years ago), the Barringer crater in Arizona and Shoemaker-Levy 9 impacting Jupiter – the first collision observed in real time on another planet. Nowadays amateur astronomers have managed to observe impacts on Jupiter in real time through their telescopes whilst imaging the giant planet.

The most important point to be borne out is that NEOs impact the Earth every day so it is not a question “if” a NEO will hit the Earth, but rather “when” it will hit and “how big” the impact will be.

The final part of the talk was on projects like NEOShield-2, pioneering science and technology for NEO impact prevention. A brief description of methods like kinetic impact, blast deflection, gravity traction, combined methods, and civil defence procedures was given.

Finally those attending could listen to another brief talk on astronomy as well as observe the skies using telescopes set up on the roof of the building.

NEOShield-2 note:

The NEOShield-2 team is very glad to have Alexei on board and very proud of his effort and commitment to the cause. We are looking forward to future events in Malta.