Ultracool dwarf binary stars break records
Astrophysicists discover the closest and oldest ultracool dwarf binary ever observed
IMAGE: ILLUSTRATION OF THE OLDEST KNOWN PAIR OF ULTRACOOL DWARF STARS THAT ORBIT EACH OTHER SO CLOSELY, THEY TAKE LESS THAN ONE EARTH DAY TO REVOLVE AROUND EACH OTHER. view more
CREDIT: ADAM BURGASSER/UC SAN DIEGO
Northwestern University and the University of California San Diego (UC San Diego) astrophysicists have discovered the tightest ultracool dwarf binary system ever observed.
The two stars are so close that it takes them less than one Earth day to revolve around each other. In other words, each star’s “year” lasts just 17 hours.
The newly discovered system, named LP 413-53AB, is composed of a pair of ultracool dwarfs, a class of very low-mass stars that are so cool that they emit their light primarily in the infrared, making them completely invisible to the human eye. They are nonetheless one of the most common types of stars in the universe.
Previously, astronomers had only detected three short-period ultracool dwarf binary systems, all of which are relatively young — up to 40 million years old. LP 413-53AB is estimated to be billions of years old — similar age to our sun — but has an orbital period that is at least three times shorter than the all ultracool dwarf binaries discovered so far.
The research was published on March 1 in the Astrophysical Journal Letters.
“It’s exciting to discover such an extreme system,” said Chih-Chun “Dino” Hsu, a Northwestern astrophysicist who led the study. “In principle, we knew these systems should exist, but no such systems had been identified yet.”
Hsu is a postdoctoral researcher in Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics(CIERA). He began this study while a Ph.D. student at UC San Diego, where he was advised by Professor Adam Burgasser.
The team first discovered the strange binary system while exploring archival data. Hsu developed an algorithm that can model a star based on its spectral data. By analyzing the spectrum of light emitted from a star, astrophysicists can determine the star’s chemical composition, temperature, gravity and rotation. This analysis also shows the star’s motion as it moves toward and away from the observer, known as radial velocity.
When examining the spectral data of LP 413-53AB, Hsu noticed something strange. Early observations caught the system when the stars were roughly aligned and their spectral lines overlapped, leading Hsu to believe it was just one star. But as the stars moved in their orbit, the spectral lines shifted in opposite directions, splitting into pairs in later spectral data. Hsu realized there were actually two stars locked into an incredibly tight binary.
Using powerful telescopes at the W.M. Keck Observatory, Hsu decided to observe the phenomenon for himself. On March 13, 2022, the team turned the telescopes toward the constellation Taurus, where the binary system is located, and observed it for two hours. Then, they followed up with more observations in July, October and December as well as January 2023.
“When we were making this measurement, we could see things changing over a couple of minutes of observation,” Burgasser said. “Most binaries we follow have orbit periods of years. So, you get a measurement every few months. Then, after a while, you can piece together the puzzle. With this system, we could see the spectral lines moving apart in real time. It’s amazing to see something happen in the universe on a human time scale.”
The observations confirmed what Hsu’s model predicted. The distance between the two stars is about 1% of the distance between the Earth and the sun. “This is remarkable, because when they were young, something like 1 million years old, these stars would have been on top of each other,” said Burgasser.
The team speculates that the stars either migrated toward each other as they evolved, or they could have come together after the ejection of a third — now lost — stellar member. More observations are needed to test these ideas.
Hsu also said that by studying similar star systems researchers can learn more about potentially habitable planets beyond Earth. Ultracool dwarfs are much fainter and dimmer than the sun, so any worlds with liquid water on their surfaces — a crucial ingredient to form and sustain life — would need to be much closer to the star. However, for LP 413-53AB, the habitable zone distance happens to be the same as the stellar orbit, making it impossible to form habitable planets in this system.
“These ultracool dwarfs are neighbors of our sun,” Hsu said. “To identify potentially habitable hosts, it’s helpful to start with our nearby neighbors. But if close binaries are common among ultracool dwarfs, there may be few habitable worlds to be found.”
To fully explore these scenarios, Hsu, Burgasser and their collaborators hope to pinpoint more ultracool dwarf binary systems to create a full data sample. New observational data could help strengthen theoretical models for binary-star formation and evolution. Until now, however, finding ultracool binary stars has remained a rare feat.
“These systems are rare,” said Chris Theissen, study co-author and a Chancellor’s Postdoctoral Fellow at UC San Diego. “But we don’t know whether they are rare because they rarely exist or because we just don’t find them. That’s an open-ended question. Now we have one data point that we can start building on. This data had been sitting in the archive for a long time. Dino’s tool will enable us to look for more binaries like this.”
JOURNAL
The Astrophysical Journal Letters
METHOD OF RESEARCH
Observational study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Discovery of the Exceptionally Short Period Ultracool Dwarf Binary LP 413-53AB
ARTICLE PUBLICATION DATE
1-Mar-2023
Resurrected supernova provides missing-link
IMAGE: AN IMAGE OF THE CENTRAL REGION OF M77 TAKEN BY THE HUBBLE SPACE TELESCOPE (LEFT), IN WHICH THE POSITION OF SN 2018IVC IS MARKED. RIGHT PANELS SHOW THE EXPANDED VIEW AROUND SN 2018IVC BASED ON THE DATA TAKEN BY ALMA, AT ~200 DAYS (UPPER RIGHT) AND ~ 1000 DAYS (LOWER RIGHT), CLEARLY SHOWING THAT THE REBRIGHTENING HAPPENED AT ABOUT ONE YEAR AFTER THE SN EXPLOSION. view more
CREDIT: CREDIT: (LEFT) BASED ON OBSERVATIONS MADE WITH THE NASA/ESA HUBBLE SPACE TELESCOPE, AND OBTAINED FROM THE HUBBLE LEGACY ARCHIVE, WHICH IS A COLLABORATION BETWEEN THE SPACE TELESCOPE SCIENCE INSTITUTE (STSCI/NASA), THE SPACE TELESCOPE EUROPEAN COORDINATING FACILITY (ST-ECF/ESA) AND THE CANADIAN ASTRONOMY DATA CENTRE (CADC/NRC/CSA). (RIGHT) ALMA (ESO/NAOJ/NRAO), K. MAEDA ET AL.
Astronomers have discovered a supernova exhibiting unprecedented rebrightening at millimeter wavelengths, providing an intermediate case between two types of supernovae: those of solitary stars and those in close-binary systems.
Many massive stars end their lives in a catastrophic explosion known as a supernova (SN). Supernovae increase rapidly in brightness, and then fade over the course of several months.
Astronomers have long known that the presence or absence of a close binary companion can affect the evolution of massive stars. In a close binary system, gravitational interactions with the binary companion will strip large amounts of material from the SN progenitor long before the final explosion. In these cases, the progenitor will be quiet up until the time of the actual SN. On the other hand, in the case of an SN progenitor with no binary companion or a distant companion, leading up to the SN explosion the progenitor will keep most of its initial mass.
Of course smart alecs will ask, “What happens when the binary is not too close and not too distant?” Not just smart alecs, astronomers also wanted to know. The break came when an international research team, led by Keiichi Maeda (Professor at the Graduate School of Science, Kyoto University) and Tomonari Michiyama (ALMA Joint Postdoctoral Fellow at the Graduate School of Science, Osaka University), used ALMA (The Atacama Large Millimeter/submillimeter Array) to monitor a supernova known as SN 2018ivc as it dimmed for about 200 days after the initial explosion. The results showed that SN 2018ivc was an unusual object, so the team decided to check up on it again, at about 1000 days after the explosion. They found that the object was actually rebrightening, the first time this phenomenon had ever been observed in millimeter wavelength radiation.
Comparison to numerical modeling suggests that interaction with an intermediate-distance binary companion about 1500 years before the SN explosion created a large hollow shell of circumstellar medium. At 200 days after the SN, the ejecta flying out from the explosion had yet to reach the shell. Then sometime between 200 and 1000 days, the ejecta collided with the circumstellar medium.
These results appeared as K. Maeda et al. “Resurrection of Type IIL Supernova 2018ivc: Implications for a Binary Evolution Sequence Connecting Hydrogen-rich and Hydrogen-poor Progenitors” in The Astrophysical Journal Letters on March 1, 2023.
JOURNAL
The Astrophysical Journal Letters
METHOD OF RESEARCH
Observational study
ARTICLE TITLE
Resurrection of Type IIL Supernova 2018ivc: Implications for a Binary Evolution Sequence Connecting Hydrogen-rich and Hydrogen-poor Progenitors
ARTICLE PUBLICATION DATE
1-Mar-2023
Aerospace: research by the Politecnico di Milano protagonist of the launch of the NASA DART impactor
Divert the trajectory of an asteroid on a collision course with the Earth, by means of a controlled impact at full speed with a space probe. This was the challenge of the DART mission (Double Asteroid Redirection Test) by NASA, successfully completed on 2
Peer-Reviewed PublicationIMAGE: DART-INFOGRAPHIC view more
CREDIT: DART
Milan, 1 March 2023 – Divert the trajectory of an asteroid on a collision course with the Earth, by means of a controlled impact at full speed with a space probe. This was the challenge of the DART mission (Double Asteroid Redirection Test) by NASA, successfully completed on 26 September 2022, in which the Politecnico was directly involved as part of the scientific team.
The first scientific results on the DART Mission have been published in the authoritative journal Nature in three different articles, co-authored by the researcher Fabio Ferrari from the Department of Aerospace Science and Technology at the Politecnico di Milano.
The article ‘Successful Kinetic Impact into an Asteroid for Planetary Defense’, describes the successful test of kinetic impact technology on the asteroid Dimorphos. The DART mission was the first to test this technology at full scale, demonstrating that it is an effective technique for planetary defence against possible asteroid threats.
The study ‘Ejecta from the DART-produced active asteroid Dimorphos’, describes the observations made using the Hubble Space Telescope on the material ejected by the impact of DART with the asteroid Dimorphos. The observations showed a complex morphology of the ejecta, conditioned by the gravitational interaction between the asteroid and the dust under the influence of solar radiation pressure.
Finally, the effectiveness of the kinetic impact of a satellite in avoiding a potential collision with the Earth is demonstrated in ‘Momentum Transfer from the DART mission Kinetic Impact on Asteroid Dimorphos’ co-authored by the professor of Flight Mechanics at the Politecnico, Michele Lavagna. The article quantifies the deflection effect produced by the high speed impact on the orbit of the binary system Didymos, showing how the ejection of the fragments generated by the impact helped to increase the efficiency of the energy exchange between the probe and the asteroid.
“DART is a historic moment for space exploration: it is not only the first planetary defence test, but it is also the first time we visit a binary asteroid (a system where two asteroids orbit around a common centre of gravity) and where we have the opportunity to observe how an asteroid can react to an external stress,” explains FabioFerrari, co-author of the scientific studies on DART. This has allowed us – and will allow us again in the coming months – to study the structure and evolutionary history of these celestial bodies, so close to us but still barely known. The Politecnico di Milano is part of the scientific team of the DART mission and has contributed to the study of the evolutionary dynamics of the Didymos binary system. These include the motion and stability of the binary system, as well as the internal structure of the two asteroids Didymos and Dimorphos. The Politecnico has also played a decisive role in the characterization of the motion of the fragments ejected following the impact, and their morphology observed through orbital and Earth-based telescopes.”
“It is the first time that an attempt has been made to divert a celestial body from its natural orbital path in a perceptible and significant way and to measure its effectiveness,” adds Michele Lavagna. And it is above all the first time that the impact has been witnessed by an extremely small satellite, LICIACube, the first European probe to travel in deep space. It played a fundamental role in acquiring images during and after the DART impact: images that helped us to understand the composition and structure of Dimorphos and the dynamics of the binary asteroid system, having recorded the sequence of formation of the fragments post impact and their expansion into the surrounding space in the minutes following the collision by DART. The Politecnico di Milano, together with the Italian National Institute of Astrophysics (INAF), contributed to the design and guidance of this small scientific satellite and is actively involved in the scientific analysis of the images acquired to reconstruct the evolution of the motion of the fragments generated.”
The Johns Hopkins Applied Physics Lab built and operated the DART spacecraft and manages the DART mission for NASA’s Planetary Defense Coordination Office as a project of the agency’s Planetary Missions Program Office. For more information about the DART mission, visit https://www.nasa.gov/dart or https://dart.jhuapl.edu . Neither Dimorphos nor Didymos poses any hazard to Earth before or after DART’s controlled collision with Dimorphos
JOURNAL
Nature
METHOD OF RESEARCH
Experimental study
ARTICLE TITLE
Momentum Transfer from the DART Mission Kinetic Impact on Asteroid Dimorphos
ARTICLE PUBLICATION DATE
1-Mar-2023
DART successfully deflected the orbit of an asteroid, but by how much?
IMAGE: ASI’S LICIACUBE SATELLITE ACQUIRED THIS IMAGE JUST AFTER ITS CLOSEST APPROACH TO THE DIMORPHOS ASTEROID, AFTER THE DOUBLE ASTEROID REDIRECT TEST, OR DART MISSION, MADE IMPACT ON SEP. 26, 2022. IN THIS IMAGE, IT IS POSSIBLE TO OBSERVE THE DIDYMOS AND DIMORPHOS FROM A DIFFERENT PERSPECTIVE, WHICH CAN BE USEFUL TO DETERMINE THE SHAPES OF THE ASTEROIDS. CREDIT: ASI/NASA view more
CREDIT: ASI/NASA
Using data from NASA’s successful double asteroid redirection test in September 2022, a team of scientists including Siegfried Eggl, an aerospace engineer at the University of Illinois Urbana-Champaign, calculated the momentum transferred to the target asteroid on impact to be greater than they expected it would be. They found the momentum was significantly enhanced by the recoil created from streams of particles produced by the impact.
“The smaller asteroid of the binary Didymos, Dimorphos, that was hit by the DART spacecraft is basically a rubble pile—an agglomeration of lots of tiny and not so tiny pebbles—so I wasn’t surprised at the larger quantity of ejecta the impact created,” said Eggl. He is one of the authors of a paper published in the journal Nature.
ASI’s LICIACube satellite acquired this image just after its closest approach to the Dimorphos asteroid, after the Double Asteroid Redirect Test, or DART mission, made impact on Sep. 26, 2022. In this image, it is possible to observe the Didymos and Dimorphos from a different perspective, which can be useful to determine the shapes of the asteroids. Credit: ASI/NASA
The team of scientists calculated the momentum transferred to Dimorphos as a result of the impact, the Beta factor, and learn its displacement with respect to its primary asteroid Didymos.
He said, going into it, they could infer the shape of Dimorphos from images recorded by DART’s DRACO camera, but without knowing the mass it was difficult to estimate the momentum transfer onto Dimophos,. After the impact, they had new information that made a big difference in their ability to make accurate calculations—they knew that the impact changed the period of Dimorphos’ orbit by 33 minutes.
“I think the most important outcome is what we've learned in terms of how we anchor our simulations,” Eggl said. “We’ve tried to derive all the deflection predictions based on first principles, but we didn't have a single, actual data point. Now we have that and can compare which results match and which ones give us a better understanding, so that we have better predictions in the future.”
The team ran Monte Carlo simulations using random combinations of variables such as whether Dimorphos was more or less massive than Didymos. Eggl’s role was to ensure that the simulations were statistically correct and accurately reflect reality.
He said, because near Earth asteroids are very diverse in their makeup, more tests like DART are needed.
The last complete image of asteroid moonlet Dimorphos, taken by the DRACO imager on NASA's DART mission from ~7 miles (12 kilometers) from the asteroid and 2 seconds before impact. The image shows a patch of the asteroid that is 100 feet (31 meters) across. Dimorphos' north is toward the top of the image. Credit: NASA/Johns Hopkins APL
“If we had pictures of the primary asteroid beforehand, our pre-impact predictions may have been more in line with the results coming out of DART,” Eggl said. “The amount of momentum transported by ejecta was not completely out of the possible range that we calculated, but it was on the high end. We need to do more tests on other kinds of asteroids, to better understand which uncertainties we are looking at when we try to deflect an actual impactor.”
Eggl noted that thanks to the joint work of his Ph.D. student Rahil Makadia and researchers at the NASA Jet Propulsion Laboratory, California Institute of Technology, we know that neither Dimorphos nor Didymos pose any hazard to Earth before or after DART’s controlled collision with Dimorphos. According to Eggl another mission conducted by the European Space Agency, Hera, will accurately measure the mass of Dimorphos by sometime in 2027. That will allow the DART team to further refine the results of world’s first dedicated asteroid deflection mission.
About the DART project, which he has been working on since it began in 2013, Eggl said, “A lot of the work I do is predictive in nature and yet to be validated. In that respect DART was unusual. The mission had a very quick turnaround. Because we had done all of the preparation and made predictions using the software and models, once we got the actual data from the mission we were able to immediately run the simulations and learn the results quickly.”
“I think what we also learned is that if people work together, we can achieve amazing things, like to actually deflect an asteroid.”
The NASA/Johns Hopkins University Applied Physics Laboratory Double Asteroid Redirection Test team which includes Eggl and two of his Ph.D. students Rahil Makadia, and Bhaskar Mondal, is receiving the 2023 AIAA Award for Aerospace Excellence. The award states it is “In recognition of humanity’s first time purposely changing the motion of a celestial object by a team of protectors of our home planet.”
The study, Momentum Transfer from the DART Mission Kinetic Impact on Asteroid Dimorphos,” by Andrew F. Cheng, et al, is published in the journal Nature. DOI: 10.1038/s41586-023-05878-z
Johns Hopkins Applied Physics Lab built and operated the DART spacecraft and manages the DART mission for NASA’s Planetary Defense Coordination Office as a project of the agency’s Planetary Missions Program Office. LICIACube is a project of the Italian Space Agency, carried out by Argotec. For more information about the DART mission, visit https://www.nasa.gov/dart or https://dart.jhuapl.edu.
JOURNAL
Nature
ARTICLE TITLE
Momentum Transfer from the DART Mission Kinetic Impact on Asteroid Dimorphos
ARTICLE PUBLICATION DATE
1-Mar-2023
Hansel and Gretel's breadcrumb trick
inspires robotic exploration of caves on
Mars and beyond
University of Arizona engineers have developed a system that allows autonomous vehicles to scout out underground habitats for astronauts
Peer-Reviewed PublicationIMAGE: IN THIS ARTIST'S IMPRESSION OF THE BREADCRUMB SCENARIO, AUTONOMOUS ROVERS CAN BE SEEN EXPLORING A LAVA TUBE AFTER BEING DEPLOYED BY A MOTHER ROVER THAT REMAINS AT THE ENTRANCE TO MAINTAIN CONTACT WITH AN ORBITER OR A BLIMP. view more
CREDIT: JOHN FOWLER/CREATIVE COMMONS (PHOTO), MARK TARBELL AND WOLFGANG FINK/UNIVERSITY OF ARIZONA
House hunting on Mars could soon become a thing, and researchers at the University of Arizona are already in the business of scouting real estate that future astronauts could use as habitats. Researchers in the UArizona College of Engineering have developed technology that would allow a flock of robots to explore subsurface environments on other worlds.
"Lava tubes and caves would make perfect habitats for astronauts because you don't have to build a structure; you are shielded from harmful cosmic radiation, so all you need to do is make it pretty and cozy," said Wolfgang Fink, an associate professor of electrical and computer engineering at UArizona.
Fink is lead author of a new paper in Advances in Space Research that details a communication network that would link rovers, lake landers and even submersible vehicles through a so-called mesh topology network, allowing the machines to work together as a team, independently from human input. According to Fink and his co-authors, the approach could help address one of NASA's Space Technology Grand Challenges by helping overcome the limited ability of current technology to safely traverse environments on comets, asteroids, moons and planetary bodies. In a nod to the fairy tale "Hansel and Gretel," the researchers named their patent-pending concept the "Breadcrumb-Style Dynamically Deployed Communication Network" paradigm, or DDCN.
A fairy tale inspires the future
"If you remember the book, you know how Hansel and Gretel dropped breadcrumbs to make sure they'd find their way back," said Fink, founder and director of the Visual and Autonomous Exploration Systems Research Laboratory at Caltech and UArizona. "In our scenario, the 'breadcrumbs' are miniaturized sensors that piggyback on the rovers, which deploy the sensors as they traverse a cave or other subsurface environment."
Continuously monitoring their environment and maintaining awareness of where they are in space, the rovers proceed on their own, connected to each other via a wireless data connection, deploying communication nodes along the way. Once a rover senses the signal is fading but still within range, it drops a communication node, regardless of how much distance has actually passed since it placed the last node.
"One of the new aspects is what we call opportunistic deployment – the idea that you deploy the 'breadcrumbs' when you have to and not according to a previously planned schedule," Fink said.
All the while, there is no need for input from the mother rover; each subordinate rover will make that determination on its own, Fink added. The system can work in one of two ways, Fink explained. In one, the mother rover acts as a passive recipient, collecting data transmitted by the rovers doing the exploration. In the other, the mother rover acts as the orchestrator, controlling the rovers' moves like a puppet master.
Machines take over
The new concept dovetails with the tier-scalable reconnaissance paradigm devised by Fink and colleagues in the early 2000s. This idea envisions a team of robots operating at different command levels – for example, an orbiter controlling a blimp, which in turn controls one or more landers or rovers on the ground. Already, space missions have embraced this concept, several with participation by UArizona researchers. For example, on Mars, the Perseverance rover is commanding Ingenuity, a robotic helicopter. A concept for another mission, which ultimately was not selected for funding, proposed sending an orbiter carrying a balloon and a lake lander to study one of the hydrocarbon seas on Saturn's moon Titan. The breadcrumb approach takes the idea one step further by providing a robust platform allowing robotic explorers to operate underground or even submerged in liquid environments. Such swarms of individual, autonomous robots could also aid in search and rescue efforts in the wake of natural disasters on Earth, Fink said.
Fink said the biggest challenge, apart from getting the rovers inside the subsurface environment in the first place, is to retrieve the data they record underground and bring it back to the surface. The DDCN concept allows a team of rovers to navigate even convoluted underground environments without ever losing contact to their "mother rover" on the surface. Outfitted with a light detection and ranging system, or lidar, they could even map out cave passages in all three dimensions, not unlike the drones that can be seen exploring an alien spacecraft in the movie "Prometheus."
"Once deployed, our sensors automatically establish a nondirected mesh network, which means each node updates itself about each node around it," said Fink, who first detailed the DDCN concept in a proposal to NASA in 2019.
"They can switch between each other and compensate for dead spots and signal blackouts," added Mark Tarbell, paper co-author and senior research scientist in Fink's laboratory. "If some of them die, there still is connectivity through the remaining nodes, so the mother rover never loses connection to the farthest node in the network."
Mission of no return
The robust network of communication nodes ensures all the data collected by the robotic explorers make it back to the mother rover on the surface. Therefore, there is no need to retrieve the robots once they have done their job, said Fink, who published the idea of using groups of expendable mobile robotic surface probes as early as 2014.
"They're designed to be expendable," he said. "Instead of wasting resources to get them into the cave and back out, it makes more sense to have them go as far as they possibly can and leave them behind once they have fulfilled their mission, run out of power or succumbed to a hostile environment."
"The communication network approach introduced in this new paper has the potential to herald a new age of planetary and astrobiological discoveries," said Dirk Schulze-Makuch, president of the German Astrobiological Society and author of many publications on extraterrestrial life. "It finally allows us to explore Martian lava tube caves and the subsurface oceans of the icy moons – places where extraterrestrial life might be present."
The proposed concept "holds magic," according to Victor Baker, a UArizona Regents Professor of Hydrology and Atmospheric Sciences, Geosciences and Planetary Sciences. "The most amazing discoveries in science come about when advances in technology provide both first-time access to a thing or place and the means of communicating what is thereby discovered to creative minds that are seeking understanding," Baker said.
Exploring hidden ocean worlds
In places that call for submersible robots, the system could consist of a lander – either floating on a lake, as might be the case on Titan, or sitting on the ice atop a subsurface ocean like on Europa – that is connected to the submarine, for example through a long cable. Here the communication nodes would act as repeaters, boosting the signal in regular intervals to prevent it from degrading. Importantly, Fink pointed out, the nodes have the capabilities to gather data themselves – for example measuring pressure, salinity, temperature and other chemical and physical parameters – and to ingest the data into the cable connecting back to the lander.
"Imagine you make it all the way to Europa, you melt your way through miles of ice, make it down to the subsurface ocean, where you find yourself surrounded by alien life, but you have no way of getting data back to the surface," he said. "That's the scenario we need to avoid."
Having developed the rovers and the communication technology, Fink's group is now working on building the actual mechanism by which the rovers would deploy the communication nodes.
"Basically, we're going to teach our 'Hansels' and 'Gretels' how to drop the breadcrumbs so they add up to a functioning mesh communication network," Fink said.
A hole in the surface of Mars, spotted by the HiRISE camera, reveals a cave below. Protected from the harsh surface of Mars, such pits are believed to be good candidates to contain Martian life, making them prime targets for possible future spacecraft, robots and even human interplanetary explorers.
CREDIT
NASA/JPL/University of Arizona
One of the experimental rovers used by Fink's team to test hardware and software related to autonomous exploration. This prototype is outfitted with cameras and other sensors for navigation.
CREDIT
Wolfgang Fink/University of Arizona
JOURNAL
Advances in Space Research
METHOD OF RESEARCH
Computational simulation/modeling
ARTICLE TITLE
A Hansel & Gretel Breadcrumb-Style Dynamically Deployed Communication Network Paradigm using Mesh Topology for Planetary Subsurface Exploration
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