Skip to main content

Contact Binary Asteroids are Common, but We’ve Never Seen One Form. So Let’s Make One

Ever want to play a game of cosmic billiards? That’s commonly how the DART mission was described when it successfully changed the orbit of a near-Earth asteroid last year. If you want an idea of how it works, just Google it and an Easter egg from the search giant will give you a general idea. But DART was more like trying to brute force a billiards break – there are many other things you can do with a set of asteroids and impactors on the galactic stage. One of the more interesting is to try to force two asteroids together to form a “contact binary” – the goal of a mission design put forward by a group of scientists from Cornell in a recent paper in Acta Astronautica.

Colby Merill and his colleagues at Cornell’s Mechanical and Aerospace Engineering department first explain why such a mission would be a good idea. Contact binaries are defined as a system when two objects are so close together that their surfaces touch. Typically, astronomers think of the objects as a pair of stars, but asteroids can also form contact binaries.

Recent estimates put the total number of contact binaries as high as 30% of all small solar system bodies, including famous ones like Arrokoth and 67P/Churyumov-Gersasimenko. That means if there are any potentially hazardous asteroids we aren’t yet aware of, there’s a fair chance it’s actually a contact binary.

Fraser discusses another potential DART successor.

Such a configuration presents a problem for planetary defense operators. Understanding where to hit a binary to deflect it makes the math much harder. Moreover, we’ve never seen one of these systems form to understand its underlying mechanisms. The standard model of this process is known as the Binary Yarkovsky-O’Keefe-Radzievskii-Paddack (BYORP) effect, by which the two asteroids, which usually begin in a standard, non-touching binary system, end up having their gravities draw each other together and touch without the catastrophic impact that would be typical of large bodies at higher speeds.

Setting up a contact binary through the BYORP effect would require a separate mission design. According to the paper, a good first effort would be to smack the asteroids into each other using an impactor. There are several advantages to this. A big one is flight heritage – the mission could use a slightly modified version of DART and a coupled observer satellite that could watch the slow-motion impact.

How slow that impact is will have a significant impact on the success of the mission. Hit the billiard ball too hard, and it will smash into its companion and cause a potentially devastating chain reaction. Hit it too softly, and there might not be enough force to push the two objects together. Plenty of math, including simulations of the forces of ejecta fragments, would go into the planning stage of any such mission.

Fraser also discusses the aftermath of the DART impact.

Those simulations require you to know some features of the planned targets, though, and the Cornell researchers have identified one. Known in strikingly formal near-asteroid parlance as (350751) 2002 AW, this system’s primary comes in at about 230 m, with a secondary partner measuring about 50 m. One potential advantage of a mission to this system is that the 50 m size of its smaller object is the minimum size limit for possible future planetary defense missions, allowing the mission to emulate a potential real planetary defense scenario.

Plenty of observation will need to take place to effectively plan where best to hit the pair, though, and with how much force to do so. The paper requests plenty of ground-based observational support, including density and orbital measurements. However, it’s unclear if there’s enough interest in the project yet to warrant diverting those resources to this new effort.

There’s also additional work to do, including developing a plan for how the observational satellite could avoid the debris cloud that will form after the impact. Another potential research area is initiating a contact using a gravity tug to force a sped-up BYORP effect.

For now, these ideas remain on the drawing board. But it’s nice to see how successful missions like DART can inspire even more ambitious ones in the future. Maybe someday, our skill at cosmic billiards will grow to include an ability to do trick shots, too.

Learn More:
Merill et al. – Creating a contact binary via spacecraft impact to near-Earth binary asteroid (350751) 2002 AW
UT – DART Had a Surprising Impact on its Target
UT – After DART Smashed Into Dimorphos, What Happened to the Larger Asteroid Didymos?
UT – Remember the DART impact? Hubble Made a Movie of the Debris

Lead Image:
Images of three contact asteroids – Arrokoth (right), 67P/Churyumov-Gerasimenko (middle), and Itokawa (left)
Credit – NASA, ESA, and JAXA

The post Contact Binary Asteroids are Common, but We’ve Never Seen One Form. So Let’s Make One appeared first on Universe Today.



from Universe Today https://ift.tt/DQZKkyB
via IFTTT
Labels:

Comments

Post a Comment

Popular posts from this blog

Researchers Match Up 12 Meteorites with the Near-Earth Asteroids They Came From

Every day meteoroids blast through our planet’s atmosphere to hit the ground as meteorites. A team of researchers in Italy traced twelve of them to progenitor asteroids that orbit in near-Earth space. Scientists treasure meteorites because they reveal information about their parent bodies. In an arXiv paper, two Italian researchers—Albino Carbognani and Marco Fenucci—analyze the characteristics of the parent bodies of 20 selected meteorites. They were able to track all but eight back to their parent asteroids. Based on their work, the pair says at least a quarter of meteorites come from collisions that happened in near-Earth space and not in the Main Belt. Meteorites from Near-Earth Asteroids: How They Got Here Many meteorites are chondritic, similar to asteroids in the Main Belt (or came from it). In their paper, the authors point out that progenitor meteoroids (including many that fall to Earth and become meteorites) formed millions of years ago following collisions between main-...
Post a Comment
Read more

JWST Takes a Detailed Look at Jupiter’s Moon Ganymede

Nature doesn’t conform to our ideas of neatly-contained categories. Many things in nature blur the lines we try to draw around them. That’s true of Jupiter’s moon Ganymede, the largest moon in the Solar System. The JWST took a closer look at Ganymede, the moon that’s kind of like a planet, to understand its surface better. Ganymede is basically a planet, except it doesn’t orbit the Sun. If it did orbit the Sun instead of Jupiter, it would be indistinguishable from a planet. It has a differentiated internal structure with a molten core that produces a magnetic field. It has a silicon mantle much like Earth’s, and has a complex icy crust with a deep ocean submerged beneath it. It has an atmosphere, though it’s thin. It’s also larger than Mercury, and almost as large as Mars. According to the authors of a new study, it’s an archetype of a water world. But even with all this knowledge of the huge moon, there are details yet to be revealed. This is especially true of its complex surface...
Post a Comment
Read more

The Ultraviolet Habitable Zone Sets a Time Limit on the Formation of Life

The field of extrasolar planet studies has grown exponentially in the past twenty years. Thanks to missions like Kepler, the Transiting Exoplanet Survey Satellite (TESS), and other dedicated observatories, astronomers have confirmed 5,690 exoplanets in 4,243 star systems . With so many planets and systems available for study, scientists have been forced to reconsider many previously-held notions about planet formation and evolution and what conditions are necessary for life. In the latter case, scientists have been rethinking the concept of the Circumsolar Habitable Zone (CHZ). By definition, a CHZ is the region around a star where an orbiting planet would be warm enough to maintain liquid water on its surface. As stars evolve with time, their radiance and heat will increase or decrease depending on their mass , altering the boundaries of the CHZ. In a recent study , a team of astronomers from the Italian National Institute of Astrophysics (INAF) considered how the evolution of star...
Post a Comment
Read more