Hubble goes hunting for small main belt asteroids
IMAGE:
THIS HUBBLE SPACE TELESCOPE IMAGE OF THE BARRED SPIRAL GALAXY UGC 12158 LOOKS LIKE SOMEONE TOOK A WHITE MARKING PEN TO IT. IN REALITY IT IS A COMBINATION OF TIME EXPOSURES OF A FOREGROUND ASTEROID MOVING THROUGH HUBBLE'S FIELD-OF-VIEW, PHOTOBOMBING THE OBSERVATION OF THE GALAXY. SEVERAL EXPOSURES OF THE GALAXY WERE TAKEN, WHAT IS EVIDENCE IN THE DASHED PATTERN. THE ASTEROID APPEARS AS A CURVED TRAIL DUE TO PARALLAX: BECAUSE HUBBLE IS NOT STATIONARY, BUT ORBITING EARTH, AND THIS GIVES THE ILLUSION THAT THE FAINT ASTEROID IS SWIMMING ALONG A CURVED TRAJECTORY. THE UNCHARTED ASTEROID IS IN INSIDE THE ASTEROID BELT IN OUR SOLAR SYSTEM, AND HENCE IS 10 TRILLION TIMES CLOSER TO HUBBLE THAN THE BACKGROUND GALAXY. RATHER THAN A NUISANCE, THIS TYPE OF DATA ARE USEFUL TO ASTRONOMERS FOR DOING A CENSUS OF THE ASTEROID POPULATION IN OUR SOLAR SYSTEM.
view moreCREDIT: NASA, ESA, PABLO GARCÍA MARTÍN (UAM); IMAGE PROCESSING: JOSEPH DEPASQUALE (STSCI); ACKNOWLEDGMENT: ALEX FILIPPENKO (UC BERKELEY)
Like boulders, rocks, and pebbles scattered across a landscape, asteroids come in a wide range of sizes. Cataloging asteroids in space is tricky because they are faint and they don't stop to be photographed as they zip along their orbits around the Sun.
Astronomers recently used a trove of archived images taken by NASA's Hubble Space Telescope to visually snag a largely unseen population of smaller asteroids in their tracks. The treasure hunt required perusing 37,000 Hubble images spanning 19 years. The payoff was finding 1,701 asteroid trails, with 1,031 of the asteroids previously uncatalogued. About 400 of these uncatalogued asteroids are below 1 kilometer in size.
Volunteers from around the world known as "citizen scientists" contributed to the identification of this asteroid bounty. Professional scientists combined the volunteers' efforts with machine learning algorithm to identify the asteroids. It represents a new approach to finding asteroids in astronomical archives spanning decades, which may be effectively applied to other datasets, say the researchers.
"We are getting deeper into seeing the smaller population of main belt asteroids. We were surprised with seeing such a large number of candidate objects," said lead author Pablo García Martín of the Autonomous University of Madrid, Spain. "There was some hint of this population existing, but now we are confirming it with a random asteroid population sample obtained using the whole Hubble archive. This is important for providing insights into the evolutionary models of our solar system."
The large, random sample offers new insights into the formation and evolution of the asteroid belt. Finding a lot of small asteroids favors the idea that they are fragments of larger asteroids that have collided and broken apart, like smashed pottery. This is a grinding-down process spanning billions of years.
An alternative theory for the existence of smaller fragments is that they formed that way billions of years ago. But there is no conceivable mechanism that would keep them from snowballing up to larger sizes as they agglomerated dust from the planet-forming circumstellar disk around our Sun. "Collisions would have a certain signature that we can use to test the current main belt population," said co-author Bruno Merín of the European Space Astronomy Centre, in Madrid, Spain .
Amateur Astronomers Teach AI to Find Asteroids
Because of Hubble's fast orbit around the Earth, it can capture wandering asteroids through their telltale trails in the Hubble exposures. As viewed from an Earth-based telescope, an asteroid leaves a streak across the picture. Asteroids "photobomb" Hubble exposures by appearing as unmistakable, curved trails in Hubble photographs.
As Hubble moves around the Earth, it changes its point of view while observing an asteroid, which also moves along its own orbit. By knowing the position of Hubble during the observation and measuring the curvature of the streaks, scientists can determine the distances to the asteroids and estimate the shapes of their orbits.
The asteroids snagged mostly dwell in the main belt, which lies between the orbits of Mars and Jupiter. Their brightness is measured by Hubble's sensitive cameras. And comparing their brightness to their distance allows for a size estimate. The faintest asteroids in the survey are roughly one forty-millionth the brightness of the faintest star that can be seen by the human eye.
"Asteroid positions change with time, and therefore you cannot find them just by entering coordinates, because at different times, they might not be there," said Merín. "As astronomers we don't have time to go looking through all the asteroid images. So we got the idea to collaborate with over 10,000 citizen-science volunteers to peruse the huge Hubble archives."
In 2019 an international group of astronomers launched the Hubble Asteroid Hunter, a citizen-science project to identify asteroids in archival Hubble data. The initiative was developed by researchers and engineers at the European Science and Technology Centre (ESTEC) and the European Space Astronomy Centre's science data center (ESDC), in collaboration with the Zooniverse platform, the world's largest and most popular citizen-science platform, and Google.
A total of 11,482 citizen-science volunteers, who provided nearly 2 million identifications, were then given a training set for an automated algorithm to identify asteroids based on artificial intelligence. This pioneering approach may be effectively applied to other datasets.
The project will next explore the streaks of previously unknown asteroids to characterize their orbits and study their properties, such as rotation periods. Because most of these asteroid streaks were captured by Hubble many years ago, it is not possible to follow them up now to determine their orbits.
The findings are published in the journal Astronomy and Astrophysics.
To learn how you can participate in citizen science projects related to NASA, visit https://science.nasa.gov/citizen-science/. Participation is open to everyone around the world, not limited to U.S. citizens or residents.
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
Learn More:
Hubble Sees Nearby Asteroids Photobombing Distant Galaxies
Tracking Evolution in the Asteroid Belt
Uncovering Icy Objects in the Kuiper Belt
Media Contact:
Claire Andreoli
NASA's Goddard Space Flight Center, Greenbelt, MD
claire.andreoli@nasa.gov
Ray Villard
Space Telescope Science Institute, Baltimore, MD
Science Contact:
Pablo García Martín
Autonomous University of Madrid, Madrid, Spain
JOURNAL
Astronomy and Astrophysics
METHOD OF RESEARCH
Observational study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Hubble Asteroid Hunter
Peptides on Interstellar Ice
International research team led by physicists at Friedrich Schiller University Jena observes formation of biomolecules under space conditions
FRIEDRICH-SCHILLER-UNIVERSITAET JENA
IMAGE:
DR SERGE KRASNOKUTSKI FROM UNIVERSITY OF JENA, GERMANY USES A VACUUM CHAMBER TO INVESTIGATE THE FORMATION OF BIOMOLECULES IN SPACE.
view moreCREDIT: IMAGE: JENS MEYER/UNIVERSITY OF JENA
Peptides are organic compounds that play a crucial role in many biological processes, for example, as enzymes. A research team led by Dr Serge Krasnokutski from the Astrophysics Laboratory at the Max Planck Institute for Astronomy at the University of Jena had already demonstrated that simple peptides can form on cosmic dust particles. However, it was previously assumed that this would not be possible if molecular ice, which covers the dust particle, contains water – which is usually the case. Now, the team, in collaboration with the University of Poitiers, France, has discovered that the presence of water molecules is not a major obstacle for the formation of peptides on such dust particles. The researchers report on their finding in the journal “Science Advances”.
Chemistry in the Icy Vacuum
“We have replicated conditions similar to those in outer space in a vacuum chamber, also adding substances that occur in so-called molecular clouds,” explains Krasnokutski. These substances include ammonia, atomic carbon, and carbon monoxide. “Thus, all the chemical elements needed for simple peptides are present,” adds the physicist.
These raw materials, Krasnokutski describes, initially form chemical precursors to amino acids known as aminoketenes. These then combine to form chains, resulting in polypeptides. “It was previously suspected that the individual aminoketenes would bond to form peptides,” the scientist explains. “However, for this step, the absence of water might be crucial as it could hinder the reaction. At the same time, most interstellar dust particles are covered with water-containing molecular ice,” says Krasnokutski. Hence, the assumption until now has been that if peptides form in space, they do so only to a limited extent.
Precise Analysis in France
“The highly precise mass spectrometric analyses now possible at the University of Poitiers, however, showed that the presence of water in the molecular ice slows down the formation of peptides by fifty percent, but they still form,” he explains. “When you consider the time scales on which astronomical processes occur, this slowdown is practically negligible.”
The question of whether the first biomolecules on our planet are of terrestrial or extraterrestrial origin – or both – will likely remain unresolved for the foreseeable future. However, outer space as a source of our life cannot be ruled out, as this discovery indicates.
JOURNAL
Science Advances
METHOD OF RESEARCH
Experimental study
ARTICLE TITLE
Formation of extraterrestrial peptides and their derivatives
ARTICLE PUBLICATION DATE
17-Apr-2024
‘Tube map’ around planets and moons made possible by knot theory
UNIVERSITY OF SURREY
Just as sat-nav did away with the need to argue over the best route home, scientists from the University of Surrey have developed a new method to find the optimal routes for future space missions without the need to waste fuel.
The new method uses mathematics to reveal all possible routes from one orbit to another without guesswork or using enormous computer power.
Danny Owen, who developed the technique at the Surrey Space Centre, said:
“Previously, when the likes of NASA wanted to plot a route, their calculations relied on either brute force or guesswork.
"Our new technique neatly reveals all possible routes a spacecraft could take from A to B, as long as both orbits share a common energy level.
"This makes the task of planning missions much simpler. We think of it as a tube map for space.”
In recent decades, space missions have increasingly relied on the ability to change the course of a satellite’s path through space without using fuel.
One way of doing this is to find ‘heteroclinic connections’ - the paths that allow spacecraft to transfer from one orbit to another without using fuel.
The mathematics for finding these paths is complex – usually calculated by using vast computing power to churn through one option after another or by making an ‘intelligent guess’ and then investigating it further.
This new technique uses an area of maths called knot theory to quickly generate rough trajectories – which can then be refined. By doing so, space agencies can gain a full list of all possible routes from a designated orbit. They can then choose the one that best suits their mission – much as you might choose a route by studying the tube map.
The technique was tested successfully on various planetary systems - including the Moon, and the Galilean moons of Jupiter. Both of these are the focus of current and future missions.
Dr Nicola Baresi, Lecturer in Orbital Mechanics at the University of Surrey, said:
“Spurred on by NASA’s Artemis programme, the new Moon race is inspiring mission designers around the world to research fuel-efficient routes that can better and more efficiently explore the vicinity of the Moon.
“Not only does our technique make that cumbersome task more straightforward, but it can also be applied to other planetary systems, such as the icy moons of Saturn and Jupiter.”
The paper is published in the journal Astrodynamics.
JOURNAL
Astrodynamics
METHOD OF RESEARCH
Computational simulation/modeling
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Applications of knot theory to the detection of heteroclinic connections between quasi-periodic orbits
ARTICLE PUBLICATION DATE
17-Apr-2024
Atmospheric isotopes reveal 4.5 billion years of volcanism on Jupiter’s moon Io
AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)
Sulfur and chlorine isotopes in the atmosphere of Jupiter’s moon Io indicate that it has been volcanically active for the entire 4.57 billion-year history of the Solar System, according to a new study. The findings offer new insights into the moon’s history. Io is the most volcanically active body in the Solar System. This extreme level of volcanic activity is the result of tidal heating from friction generated within the moon’s interior as it is pulled between Jupiter and its neighboring moons of Europa and Ganymede. However, how long Io has hosted such extensive volcanism isn’t fully understood. Due to the moon’s current level of volcanic activity, the surface of Io is constantly being reworked, leaving a geological record of only the most recent million years of its history. Stable isotopic measurements of volatile elements in Io’s atmosphere could provide information on the history of volcanism on Io. Katherine de Kleer and colleagues used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe the gasses in Io’s tenuous atmosphere and determine the stable isotopic radios of sulfer- and chlorine-bearing molecules. de Kleer et al. found that both elements are highly enriched in heavy isotopes compared to average Solar System values due to the loss of lighter isotopes from the upper atmosphere as material is continuously recycled between Io’s interior and atmosphere. The findings indicate that Io has lost 94% to 99% of the sulfur that undergoes this outgassing and recycling process. According to the authors, this would require Io to have had its current level of volcanic activity for its entire lifetime.
JOURNAL
Science
ARTICLE TITLE
Isotopic evidence of long-lived volcanism on Io
ARTICLE PUBLICATION DATE
18-Apr-2024
The CTAO enters a new phase of growth
VIDEO:
ON THURSDAY, 18 APRIL, DURING THE CLOSING SESSION OF THE CTAO SCIENCE SYMPOSIUM AT TEATRO DUSE IN BOLOGNA, THE DIRECTOR GENERAL OF THE CTAO, DR. STUART MCMULDROCH, OFFICIALLY ANNOUNCED THE OBSERVATORY’S NEW PHASE OF GROWTH. SUPPORTED BY THE 30M EURO ENDORSEMENT BY THE CTAO’S GOVERNING BODIES IN SEPTEMBER 2023, THIS NEW PERIOD PUTS AN END TO THE DESIGN PHASE OF THE OBSERVATORY, AS IT EMBARKS ON MAJOR INFRASTRUCTURE DEVELOPMENT TO OPERATE INTERMEDIATE TELESCOPE ARRAY CONFIGURATIONS IN THE UPCOMING YEARS. TO SHOWCASE THIS MILESTONE, STUART ALSO LAUNCHED THE CTAO’S NEW VISUAL IDENTITY AND WEBSITE DURING HIS TALK. #CTAOisGrowing
view moreCREDIT: CTAO
Bologna, Italy – On Thursday, 18 April, during the closing session of the CTAO Science Symposium at Teatro Duse in Bologna, the Managing Director of the CTAO, Dr. Stuart McMuldroch, officially announced the Observatory’s new phase of growth. Supported by the 30M Euro endorsement by the CTAO’s governing bodies in September 2023, this new period puts an end to the design phase of the Observatory, as it embarks on major infrastructure development to operate intermediate telescope array configurations in the upcoming years.
“We are moving from individual prototype telescopes to building intermediate array configurations on both sites in Spain and Chile,” explained Dr. McMuldroch during his presentation. “While our goal is to reach the Alpha Configuration, these subsets will already be more powerful than any existing instrument.”
“The intermediate array configurations will have a performance two to three times better than the current generation of ground-based instruments, allowing the CTAO to detect fainter sources and minute-scale variability from gamma-ray signals,” says Roberta Zanin, CTAO Project Scientist.
The growth of the CTAO will not only be apparent in terms of hardware, but also software and personnel. Firstly, the Observatory will start applying advanced software packages, moving from testing to integrating key systems that control the telescopes and process data. Additionally, the CTAO Central Organisation will double its staff to support the advancement of the Observatory on all fronts, from science and engineering to computing and administration.
To showcase this milestone, Stuart also launched the CTAO’s new visual identity and website during his talk. An important update is that the "CTAO" will now define the Observatory and international project, discontinuing the term "CTA."
“The CTAO is built thanks to a growing international partnership composed of various teams with different tasks, scopes and even management, but who share a common goal: to build the world’s largest gamma-ray observatory to achieve transformational science,” says Stuart. “The "CTAO" encompasses that joint effort, representing all the groups involved.”
The CTAO’s new logo and brand reflect this fresh phase of growth and collaboration with a clean, modern aesthetic that clearly positions the Observatory for its current and future status in the field. The website is the most visible manifestation of this transition, providing an immersive and engaging interface for the general public and scientists to interact with the science, technology and partners behind the CTAO.
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