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

More Data and Machine Learning has Kicked SETI Into High Gear

For over sixty years, astronomers and astrophysicists have been engaged in the Search for Extraterrestrial Intelligence (SETI). This consists of listening to other star systems for signs of technological activity (or “technosignatures), such as radio transmissions. This first attempt was in 1960, known as Project Ozma, where famed SETI researcher Dr. Frank Drake (father of the Drake Equation) and his colleagues used the Robert C. Byrd Green Bank Telescope in West Virginia to conduct a radio survey of Tau Ceti and Epsilon Eridani. Since then, the vast majority of SETI surveys have similarly looked for narrowband radio signals since they are very good at propagating through interstellar space. However, the biggest challenge has always been how to filter out radio transmissions on Earth – aka. radio frequency interference (RFI). In a recent study, an international team led by the Dunlap Institute for Astronomy and Astrophysics (DIAA) applied a new deep-learning algorithm to data collecte...
Post a Comment
Read more

eROSITA Sees Changes in the Most Powerful Quasar

After almost seventy years of study, astronomers are still fascinated by active galactic nuclei (AGN), otherwise known as quasi-stellar objects (or “quasars.”) These are the result of supermassive black holes (SMBHs) at the center of massive galaxies, which cause gas and dust to fall in around them and form accretion disks. The material in these disks is accelerated to close to the speed of light, causing it to release tremendous amounts of radiation in the visible, radio, infrared, ultraviolet, gamma-ray, and X-ray wavelengths. In fact, quasars are so bright that they temporarily outshine every star in their host galaxy’s disk combined. The brightest quasar observed to date, 100,000 billion times as luminous as our Sun, is known as SMSS J114447.77-430859.3 (J1144). This AGN is hosted by a galaxy located roughly 9.6 billion light years from Earth between the constellations Centaurus and Hydra. Using data from the eROSITA All Sky Survey and other space telescopes, an international t...
Post a Comment
Read more

The First Close-Up Picture of Star Outside the Milky Way

Like a performer preparing for their big finale, a distant star is shedding its outer layers and preparing to explode as a supernova. Astronomers have been observing the huge star, named WOH G64, since its discovery in the 1970s. It’s one of the largest known stars, and also one of the most luminous and massive red supergiants (RSGs). The star is surrounded by an envelope of expelled star-stuff, which could indicate it’s getting ready to explode. WOH G64 isn’t in the Milky Way; it’s in the Large Magellanic Cloud (LMC), the Milky Way’s largest satellite galaxy. Getting these detailed image is quite a feat for the ESO’s Very Large Telescope Interferometer. It’s also quite an accomplishment for the team of scientists behind the image. They’ve published their images and the results of their observations of the star in the journal Astronomy and Astrophysics. Their research is titled “ Imaging the innermost circumstellar environment of the red supergiant WOH G64 in the Large Magellanic ...
Post a Comment
Read more