Asteroids, Comets, and Meteors

[firestar464]

NASA's Lucy spacecraft discovers 2nd asteroid during Dinkinesh flyby

https://phys.org/news/2023-11-nasa-lucy ... eroid.html

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Near Earth Asteroid May Be a Chunk of the Moon
by Niranjana Rajalakshmi
October 24, 2023

Introduction:

(Futurity) In 2021, a team of astronomers suggested that a recently discovered near-Earth asteroid, Kamo`oalewa, could be a chunk of the moon. Two years later, another research group finds that a rare pathway could have enabled this to happen.

So far, only distant asteroids from beyond the orbit of Mars have been considered a source of near-Earth asteroids, says Renu Malhotra, professor of planetary sciences at the University of Arizona and a senior author of the paper in the journal Communications Earth & Environment.
“We are now establishing that the moon is a more likely source of Kamo`oalewa,” Malhotra says.

The implication is that many more lunar fragments remain to be discovered among the near-Earth asteroid population.

Read more here: https://www.futurity.org/near-earth-as ... 90712-2/

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NASA's Lucy spacecraft discovers 2nd asteroid during Dinkinesh flyby

https://phys.org/news/2023-11-nasa-lucy ... eroid.html

Hidden Moon Discovered During Asteroid Flyby Isn't What We Thought
by Michele Starr
November 8, 2023

Introduction:

(Science Alert) It seems like yesterday we were marveling over Dinkinesh (because it practically was) and its secret little moon, and the main belt asteroid has already given us another huge surprise.

The small moonlet orbiting the larger rock, NASA scientists have discovered, is not one moon at all. It's two moons that are glued together like a little snowman, in a type of object called a contact binary.

You may have seen this before, in outer Solar System object Arrokoth – but Dinkinesh's little double moon is the first time we've seen one orbiting an asteroid.

"Contact binaries seem to be fairly common in the Solar System," says astronomer John Spencer of the Southwest Research Institute (SwRI).
"We haven't seen many up-close, and we've never seen one orbiting another asteroid. We'd been puzzling over odd variations in Dinkinesh's brightness that we saw on approach, which gave us a hint that Dinkinesh might have a moon of some sort, but we never suspected anything so bizarre!"

Read more here: https://www.sciencealert.com/hold-up-h ... -thought



Two moonlets for the price of one, like two gummi bears stuck together.
NASA/Goddard/SwRI/Johns Hopkins APL

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Halley’s Comet Has Begun Its 38-Year Journey Back Toward Earth
by Regina Seinra
December 12, 2023

Introduction:

(My Modern Met) Halley's Comet is one of the most fascinating astronomic events ever, with records dating back to a thousand years ago. It was last visible from Earth in 1986, and since it comes around every 75 to 79 years, its next sighting will take place in July 2061. And while that seems a while away, we can now start looking forward to its return. As of December 8, 2023, Halley's Comet is on its way back through the solar system towards Earth.

The comet travels around the Sun in a flattened elliptical orbit that takes it beyond the outer limits of the solar system, before bringing it back right around the Sun. And after decades of traveling away from our star, it has reached the farthest point of its orbit, also known as aphelion. Located 3.27 billion miles away from the Sun, it's roughly 472.2 million miles beyond the orbit of Neptune. The last time Halley's Comet was at this point in its orbit was in April 1948.

Now that Halley's comet is on its way back, it means that for the first time in nearly 38 years it will be getting closer to the Sun. It currently holds a speed of 0.565 miles per second, or about 2,034 miles per hour, which is expected to increase as it gets closer to the inner solar system. “In concert with Kepler's second law of motion, a celestial body moves fastest when it is at perihelion and slowest at aphelion,” writes Joe Rao from Space. So, once Halley passes through aphelion, its orbital velocity will begin to—very slowly at first—increase, on its way inbound toward the Sun.”

Halley's Comet last reached perihelion—its closest point to the Sun—on February 9, 1986, and it will be at that point again on July 28, 2061. Since the comet will be on the same side of the Sun as the Earth during the summer, it will appear at least 10 times brighter than it did 38 years ago—light pollution permitting.

Read more here: https://mymodernmet.com/halleys-comet- ... -earth/

[wjfox]

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Miniaturized Jumping Robots Could Study an Asteroid’s Gravity
by Andy Tomaswick
December 23, 2023

Introduction:

(Universe Today) Missions focusing on small bodies in the solar system have been coming thick and fast lately. OSIRIS-Rex, Psyche, and Rosetta are all examples of projects that planned or did rendezvous with a small body in the solar system. But one of their biggest challenges is understanding the gravity of these bodies – which was especially evident when Philae, Rosetta’s lander, had a hard time staying on the surface of its intended comet. A new idea from researchers at the University of Colorado Boulder and NASA’s Jet Propulsion Laboratory could help solve that problem – by bouncing small probes around.

The concept, called Gravity Poppers, resulted from a NIAC grant back in 2020. The idea is simple enough – release a bunch of probes onto the surface of a small body and have them periodically jump off it. When they do so, keep track of them. If you know the force they jumped off with and can track them as they return to the surface, you can estimate the gravity of the area they’re floating over more accurately than alternative techniques.
Scientists use three main alternative techniques to calculate the gravity of small bodies – radar tomography, seismic imaging, and gravimetry. Each has disadvantages that the Gravity Poppers can overcome.

Radar tomography uses reflections of radio signals to estimate what the gravity is like in a particular area. However, it’s difficult to penetrate the deeper sections of a small body. Some materials don’t reflect electromagnetic waves at all, making it impossible to characterize areas with these materials.

Seismic imaging is commonly used on Earth. By tracking the movement of seismic waves across the surface of a body, scientists can estimate the gravity of regions surrounding them. However, some small bodies, especially asteroids, are just piles of rubble with no internal coherent structure. Seismic waves don’t do very well in such environments. Ryugu, the asteroid Hayabusa-2 visited, absorbed the seismic energy of an impact event such that the spacecraft couldn’t even discern any changes in its surface features.

Read more here: https://www.universetoday.com/164977/m ... e-164977

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NASA's Asteroid Sampler Begins its New Mission with a New Name
OSIRIS-REx is now OSIRIS-APEX, and it's on the way to an asteroid encounter in 2029.
By Ryan Whitwam December 27, 2023

https://www.extremetech.com/science/nas ... a-new-name
NASA's OSIRIS-REx mission was a smashing success—probably. Technicians are still struggling to open the sample canister that was delivered to Earth in October, but the spacecraft has a whole new mission to complete while NASA puzzles over those stuck screws. NASA flipped the switch from OSIRIS-REx to OSIRIS-APEX. This endeavor will end with a visit to another

asteroid, this one fresh off a close encounter with Earth.

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NASA Reveals Massive OSIRIS-REx Asteroid Sample
The mission is likely a success several times over.
By Ryan Whitwam January 24, 2024
https://www.extremetech.com/science/nas ... oid-sample

NASA's OSIRIS-REx mission collected a sample from the asteroid Bennu in 2020, returning its precious cargo to Earth in late 2023. However, technicians at Johnson Space Center had more trouble than expected getting a look at the payload. NASA reports that the canister has finally been opened and photographed. You're looking at a big, heaping mound of material from the dawn of the solar system.

OSIRIS-REx was designed to scoop up at least 60 grams of material from the asteroid, which is one of a class of objects that have remained unaltered since the formation of the solar system. Even before opening the container, NASA collected 70 grams of asteroidal dust from the exterior of the Touch-and-Go Sample Acquisition Mechanism (TAGSAM). So, the mission was already a success, but now it's a success several times over.

While the spacecraft dropped off the sample container last year, we're only getting a look inside now because NASA had trouble opening it. The TAGSAM is sealed with 35 fasteners, and two of them refused to budge with the approved tools. NASA ended up designing custom tools that could be used safely inside the sealed glovebox to loosen the bolts. It reported success earlier this month, but it delayed opening the container until late last week.

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Asteroid that Impacted Near Berlin Identified as a Rare Aubrite
February 5, 2024

Introduction:

(Eurekalert) February 5, 2024, Mountain View, CA – The official classification now aligns with what many suspected from merely looking at the images of the strange meteorites that fell near Berlin on January 21, 2024. They belong to a rare group called “aubrites”.

“They were devilishly difficult to find because, from a distance, they look like other rocks on Earth,” said SETI Institute meteor astronomer Dr. Peter Jenniskens. “Close up, not so much.”

Jenniskens traveled from San Francisco to Berlin to search the fields just south of the village of Ribbeck with Museum für Naturkunde (MfN) researcher Dr. Lutz Hecht, guiding a team of students and staff from the MfN, the Freie Universität Berlin, the Deutches zentrum für Luft und Raumfahrt, and the Technische Universität Berlin in the days following the fall.

“Even with superb directions by meteor astronomers Drs. Pavel Spurný, Jiří Borovička and Lukáš Shrbený of the Astronomical Institute of the Czech Academy of Sciences, who calculated how the strong winds blew the meteorites, and predicted that these could be rare enstatite-rich meteorites based on the light emitted by the fireball, our search team initially could not easily spot them on the ground,” said Jenniskens.

Unlike other meteorites which have a thin crust of black glass from atmospheric heat, these meteorites have a mostly translucent glass crust.

Read more here: https://www.eurekalert.org/news-releases/1033487

[wjfox]

Water found on the surface of an asteroid for the 1st time ever

By Samantha Mathewson
published about 13 hours ago

Water molecules have been detected on the surface of an asteroid for the first time, revealing new clues about the distribution of water in our solar system.

Scientists studied four silicate-rich asteroids using data gathered by the now-retired Stratospheric Observatory for Infrared Astronomy (SOFIA), a telescope-outfitted plane operated by NASA and the German Aerospace Center.

Observations by SOFIA's Faint Object InfraRed Camera (FORCAST) instrument showed that two of the asteroids — named Iris and Massalia — exhibit a specific wavelength of light that indicated the presence of water molecules at their surface, a new study reports.

"Asteroids are leftovers from the planetary formation process, so their compositions vary depending on where they formed in the solar nebula," study lead author Anicia Arredondo, of the Southwest Research Institute in San Antonio, said in a statement. "Of particular interest is the distribution of water on asteroids, because that can shed light on how water was delivered to Earth."

https://www.space.com/water-detected-as ... time-sofia



Image credit: Courtesy of NASA/Carla Thomas/SwRI)

[wjfox]

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News Release. Limitations regarding length of citation therefore do not apply.
Astronomers Confirm a New “Trojan” Asteroid that Shares an Orbit with Mars
by
March 21, 2024

Introduction:

(IAC) Using observations made with the Gran Telescopio Canarias (GTC) a study led from the Instituto de Astrofísica de Canarias (IAC) and the Universidad Complutense de Madrid (UCM) has confirmed that the asteroid 2023 FW14, discovered last year, is accompanying the red planet in its journey around the Sun, ahead of Mars and in the same orbit. With this new member, the group of Trojans which accompany Mars has increased in number to 17. But it shows differences in its orbit and chemical composition which may indicate that it is a captured asteroid, of a primitive type. The results are published in the prestigious journal Astronomy & Astrophysics.

A team from the Instituto de Astrofísica de Canarias (IAC) and the Universidad Complutense de Madrid (UCM) has observed and described for the first time the object 2023FW14, a Trojan asteroid which shares its orbit with Mars. After Jupiter, the red planet is the one which has the largest number of known Trojans, 17 with this new incorporation.

The Trojan asteroids are small bodies of the Solar System which share the orbit of a planet, occupying one of the points of stable equilibrium called the Lagrange points, situated 60º in front of (L4) and 60º behind (L5) the planet.

For the object 2023 FW14, the numerical simulations carried out at UCM during 2023 and 2024 have confirmed that it is an L4 Trojan, which means that it travels ahead of Mars, and is the second known Trojan of this type, after asteroid 1999 UJ7.

Although the majority of the Martian asteroids seem to have accompanied the planet since the epoch of its formation, 2023 FW14 arrived at its Trojan trajectory about a million years ago, and it may leave it in some 10 million years, according to the numerical results obtained.

”While the orbital evolution of the 16 previously known Trojans shows long term stability, the orbit of the new one is not stable” explains Raul de la Fuente Marcos, a researcher in the Department of Earth Science and Astrophysics at the UCM, who has led the study.”There are two possibilities for its origin: it could be a fragment of the Trojan 1999 UJ7, or it may have been captured from the population of asteroids close to the Earth which cross the orbit of Mars” he adds.

Additional extract:

Increasing the number of known Martian Trojans allows researchers to deepen their understanding of these objects, whose existence was first predicted from mathematical calcuiations. “Studying real Trojans rather than only those predicted mathematically allows us to test the reliability of our theoretical models”, concludes de la Fuente Marcos.

Read more here: https://www.iac.es/en/outreach/news/as ... orbit-mars

Earth has only two known trojans but it is difficult to study them.

Source: https://www.iflscience.com/mars-has-a- ... rbit-73511

[wjfox]

[Time_Traveller]

NASA shuts down NEOWISE asteroid hunter after almost 15 years in space

published 21 hours ago



A prolific NASA asteroid-hunting mission has come to an end.

Engineers sent a final command to the agency's NEOWISE (Near-Earth Object Wide-field Infrared Survey Explorer) spacecraft on Thursday (Aug. 8), ordering the probe to turn off its transmitter after nearly 15 years of operation in low Earth orbit.

"The NEOWISE mission has been an extraordinary success story as it helped us better understand our place in the universe by tracking asteroids and comets that could be hazardous for us on Earth," Nicola Fox, associate administrator for the Science Mission Directorate at NASA Headquarters, said in a statement on Thursday.

"While we are sad to see this brave mission come to an end, we are excited for the future scientific discoveries it has opened by setting the foundation for the next generation planetary defense telescope," she added.

NEOWISE launched in December 2009 with a different name and a different mission. Originally called WISE (Wide-field Infrared Survey Explorer), the probe scanned the entire infrared sky over the course of a seven-month prime mission. It did so "with far greater sensitivity than previous surveys," NASA officials wrote in the same statement.

https://www.space.com/nasa-shuts-down-n ... spacecraft

[wjfox]

[Time_Traveller]

Dinosaur-killing asteroid was a rare rock from beyond Jupiter, new study reveals

published 6 hours ago

The space rock that wiped out the dinosaurs 66 million years ago was a rare strike from an asteroid beyond Jupiter, a new study details. The finding pins down the nature of the fateful space rock and its origin within our solar system, and may benefit technology that forecasts asteroid strikes on our planet.

Most scientists agree that the Chicxulub impactor — named after the community in modern-day Mexico near the 90-mile-wide (145 kilometers) crater carved by the rock — came from within our solar system. But its precise origins remain unclear, due to a lack of clear chemical evidence that wasn't contaminated by Earth's own material. Now, in remnants of the impactor collected from European regions of our planet's crust, scientists have found the chemical composition of a rare element called ruthenium to be similar to that within asteroids hovering between the orbits of Mars and Jupiter.

The element is a "genetic fingerprint" of rocks in the main asteroid belt, where the fateful city-size rock was parked before it struck Earth 66 million years ago, Mario Fischer-Gödde, a scientist at the Institute of Geology and Mineralogy at the University of Cologne in Germany who led the new study, told Live Science. The asteroid was likely nudged toward Earth either by collisions with other space rocks or by influences in the outer solar system, where gas giants like Jupiter harbor immense tidal forces capable of disturbing otherwise stable asteroid orbits.

The findings rely on a new technique that essentially breaks every chemical bond bolstering a rock sample while it is stored in a sealed tube, allowing scientists to measure the specific levels of ruthenium in the Chicxulub impactor. The element has remained remarkably stable over billions of years in the face of Earth's frequent, landscape-recycling geologic activity, said Fischer-Gödde, who developed the new technique over the past decade and is one of just a handful of experts in the world who can precisely analyze the rare element.

The researchers compared the results to samples from other asteroid impact sites in South Africa, Canada and Russia, and also to a couple of carbonaceous meteorites, which dominate the outer region of the main asteroid belt. Ruthenium's chemical signatures in the Chicxulub impactor were consistent only with those of the carbonaceous meteorites, pointing to its origin in the outer solar system, the team reported in a study published Thursday (Aug. 15) in the journal Science.

https://www.space.com/asteroid-chicxulu ... d-jupiter/

[firestar464]

NASA's DART impact permanently changed the shape and orbit of asteroid moon, new study shows

https://phys.org/news/2024-08-nasa-dart ... orbit.html

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Small asteroid to hit Earth's atmosphere TODAY

Source: EarthSky.org, ESA

Heads up! A small asteroid – approximately 1 meter (3 feet) wide – will strike Earth’s atmosphere today (September 4, 2024) over the Philippines around 16:46 UTC according to the European Space Agency. That’s after midnight tonight in the Philippines. And it’s 11:46 a.m. CDT on Wednesday, September 4, for us in North America. The asteroid is expected to burn up in Earth’s atmosphere above the area of Luzon. It’s expected to create a bright fireball for anyone watching! If you’re in the Philippines, go outside and look around 12:46 a.m. PHST on Thursday, September 5.

This is only the 9th time we’ve spotted an asteroid before it’s struck us. And it was Jacqueline Fazekas at the Catalina Sky Survey in Arizona who discovered this asteroid just hours ago. Jacqueline discovered the object about eight hours before its predicted impact. The asteroid has been given the provisional designation CAQTDL2.

Read more: https://earthsky.org/space/small-astero ... 87279acab8

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Our Solar System Might Be More Crowded Than Once Believed
New research shows that the outer Kuiper Belt likely contains an abundance of 'new' small bodies.
By Adrianna Nine September 9, 2024

Researchers in Japan have found evidence for an abundance of novel celestial bodies at the outskirts of the Kuiper Belt. Using two complementary pieces of space imaging equipment, they've confirmed the existence of two dozen "new" objects and developed a strategy for locating and investigating even more. Their work could change the way we view and study the elusive outer solar system.

The Kuiper Belt is an icy, ring-shaped region just beyond Neptune's orbit that contains Pluto and several other dwarf planets. Because of its distance from Earth, this cosmic donut is mysterious. Observing Kuiper objects from the ground severely limits how much of a comet or dwarf planet astronomers can see, but observing them from space is a tall order: Spacecraft must be capable of traveling roughly 4 billion miles (6.4 billion kilometers) to the Kuiper Belt and then capturing data to send back home. Only NASA's New Horizons spacecraft—one of five spacecraft that have reached the outer solar system—has managed to fly through the Kuiper Belt and observe the objects that exist there.

https://www.extremetech.com/science/our ... e-believed