Asteroid Dimorphos- Escaping of Boulders

Asteroid Dimorphos- Escaping of Boulders

Hubble saw escaping of boulders from Asteroid Dimorphos. If you are interested in knowing about its discovery, then this blog is for you.

Asteroid Dimorphos
Image of the asteroid Dimorphos, with compass arrows, scale bar, and color key for reference. The north and east compass arrows show the orientation of the image on the sky. Note that the relationship between north and east on the sky (as seen from below) is flipped relative to direction arrows on a map of the ground (as seen from above).
Credits: NASA, ESA, David Jewitt (UCLA); Alyssa Pagan (STScI)

Hubble Telescope Discovers Asteroid Dimorphos’ Post-DART Impact Drama

“Shake, Rattle, and Roll,” a popular rock song from 1954, could be the theme music for the discovery made by the Hubble Space Telescope about what is happening to the asteroid Dimorphos after NASA’s DART (Double Asteroid Redirection Test) experiment. On September 26, 2022, DART hit Dimorphos on purpose, which slightly changed its path around the bigger asteroid Didymos.

Astronomers have found a group of boulders that may have been shaken off the asteroid Dimorphos when NASA slammed the half-ton DART impactor spaceship into Dimorphos at about 14,000 miles per hour. Hubble’s sensitivity made this possible.

Asteroid Dimorphos Unveils Boulders Ejected Post-DART Impact

Hubble photometry shows that the 37 loose rocks range in size from 3 feet to 22 feet across. They are moving away from the asteroid at a little more than a half-mile per hour, which is about as fast as a big tortoise can walk. About 0.1% of the mass of Dimorphos can be found in these rocks.

David Jewitt of the University of California at Los Angeles, a planetary scientist who has been using Hubble to track changes in the asteroid during and after the DART impact, said:

“This is a spectacular observation – much better than I expected. We see a cloud of boulders carrying mass and energy away from the impact target. The numbers, sizes, and shapes of the boulders are consistent with them having been knocked off the surface of Dimorphos by the impact,”

“This tells us for the first time what happens when you hit an asteroid and see material coming out up to the largest sizes. The boulders are some of the faintest things ever imaged inside our solar system.”

Hubble Unveils New Dimension: Hera Spacecraft to Study DART Experiment’s Aftermath

Jewitt says that this opens up a new dimension for studying the aftermath of the DART experiment using the European Space Agency’s upcoming Hera spacecraft, which will arrive at the binary asteroid in late 2026. Hera will perform a detailed post-impact survey of the targeted asteroid.

Jewitt said:

“The boulder cloud from Asteroid Dimorphos will still be dispersing when Hera arrives. It’s like a very slowly expanding swarm of bees that eventually will spread along the binary pair’s orbit around the Sun.”
Most likely, the boulders are not parts of the small asteroid that broke up when it hit. They were already spread out across the surface of the asteroid, as seen in the last close-up picture taken by the DART spacecraft just two seconds before the crash when it was only seven miles above the surface.

Hubble Observations Shed Light on DART Impact: Estimated Crater Size and Dimorphos’ Formation

Jewitt estimates that the impact shook off two percent of the boulders on the asteroid’s surface. He says the boulder observations by Hubble also give an estimate for the size of the DART impact crater.

image of the asteroid Dimorphos
This is the last complete image of the asteroid Dimorphos, as seen by NASA’s DART (Double Asteroid Redirection Test) impactor spacecraft two seconds before impact. The Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO) imager aboard captured a 100-foot-wide patch of the asteroid. The DART spacecraft streamed these images from its DRACO camera back to Earth in real time as it approached the asteroid. DART successfully impacted its target on September 26, 2022. Credits: NASA, APL

He said:

“The boulders could have been excavated from a circle of about 160 feet across (the width of a football field) on the surface of Dimorphos,”. Hera will eventually determine the actual crater size.

Long ago, Dimorphos may have formed from pieces of rock that the bigger asteroid Dimorpho shrew out into space. The parent body may have spun up too quickly, or it may have lost some of its mass after a near-miss with another object. The material that was thrown out made a ring that was pulled together by gravity to make Dimorphos. This would make it a flying pile of rocks and rock pieces that are only loosely held together by gravity. So, it’s likely that the inside isn’t solid but has more of a structure like a bunch of grapes.

Mystery of Ejected Rocks from Asteroid Dimorphos Hubble Observations Offer Clues

It’s not clear how the rocks got off the surface of the asteroid dimorphos. They might be part of an ejecta plume that Hubble and other telescopes saw and took pictures of. Or, the impact could have sent an earthquake wave through the asteroid, like hitting a bell with a hammer, shaking the surface debris loose.

“If we follow the boulders in future Hubble observations, then we may have enough data to pin down the boulders’ precise trajectories. And then we’ll see in which directions they were launched from the surface,” said Jewitt.

The DART and LICIACube (Light Italian CubeSat for Imaging of Asteroids) teams have also been looking at rocks found in pictures taken by the LICIACube LUKE (LICIACube Unit Key Explorer) camera in the minutes after DART’s impact.

The Hubble Space Telescope is a project that NASA and ESA worked on together. The telescope is run by NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The Hubble and Webb science operations are run by the Space Telescope Science Institute (STScI) in Baltimore, Maryland. The Association of Universities for Research in Astronomy, which is based in Washington, D.C., runs STScI for NASA.

Hubble Sets Out on Mission to Discover an Intermediate-sized Black Hole

Hubble Sets Out on Mission to Discover an Intermediate-sized Black Hole

Astronomers using NASA’s Hubble Space Telescope have discovered what they believe to be some of the greatest evidence yet for the presence of a rare type of “intermediate-sized” black hole lurking in the heart of the nearest globular star cluster to Earth, about 6,000 light-years distant.

What are the formation, distribution, and rarity of intermediate-mass black holes?

Almost all black holes appear to come in two sizes, similar to strong gravitational pits in the fabric of space: small and gargantuan. Our galaxy is thought to be strewn with 100 million tiny black holes (many times the mass of our Sun) formed by exploding stars. The cosmos is teeming with supermassive black holes, which are situated in the centers of galaxies and weigh millions or billions of times the mass of our Sun.

An intermediate-mass black hole, weighing between 100 and 100,000 solar masses, is a long-sought missing link.

How would they form, where would they congregate, and why do they appear to be so uncommon?

Using a variety of observational approaches, astronomers have detected more probable intermediate-sized black holes. Three of the finest possibilities — 3XMM J215022.4055108, discovered by Hubble in 2020, and HLX-1, discovered in 2009 — live in dense star clusters on the edges of neighboring galaxies. Each of these hypothetical black holes has tens of thousands of suns in mass and may have formerly resided in the centers of dwarf galaxies. NASA’s Chandra X-ray Observatory has also aided in the discovery of numerous probable intermediate black holes, including a large sample in 2018.

Much closer to home, a number of probable intermediate-sized black holes have been discovered in dense globular star clusters around our Milky Way galaxy. For example, Hubble researchers reported the possible presence of an intermediate-mass black hole in the globular cluster Omega Centauri in 2008. These and other intermediate-mass black hole discoveries remain inconclusive and do not rule out alternate hypotheses for a variety of reasons, including the need for further data.

Eduardo Vitral:

Hubble’s unique capabilities have now been utilized to hone in on the core of the globular star cluster Messier 4 (M4), allowing for more precise black-hole hunting than prior efforts. “You can’t do this kind of science without Hubble,” said Eduardo Vitral, lead author of an article to be published in the Monthly Notices of the Royal Astronomical Society.

What Vitral’s team discovered and what was its significance?

Vitral’s team discovered a probable 800 solar-mass intermediate-sized black hole. Although the alleged object cannot be seen, its mass can be determined by observing the motion of stars caught in its gravitational field, similar to bees swarming around a hive. Measuring their movement needs time and precision. This is where Hubble achieves something that no other modern telescope can. Astronomers examined 12 years of Hubble M4 data and resolved pinpoint stars.

His team believes the black hole in M4 could be 800 times the mass of our Sun. Alternative possibilities for this object, such as a compact center cluster of unresolved stellar remains like neutron stars or smaller black holes revolving around one other, are ruled out by Hubble’s observations.

Eduardo Vitral:

“We are confident that we have a very small region with a large concentration of mass.” “It’s about three times smaller than the densest dark mass we’ve found in other globular clusters,” Vitral added. “When we consider a collection of black holes, neutron stars, and white dwarfs segregated at the cluster’s center, the region is more compact than what we can reproduce with numerical simulations.” They are not capable of forming such a dense concentration of mass.”

Credits: NASA’s Goddard Space Flight Center; Lead Producer: Paul Morris

What is the nature of the central mass in the globular cluster and its impact on stellar motions?

A collection of closely packed objects would be dynamically unstable. If the object isn’t a single intermediate-sized black hole, the observed stellar motions would require an estimated 40 smaller black holes squeezed into an area only one-tenth of a light-year across. As a result, they would merge and/or be expelled in an interplanetary pinball game. “We measure the motions and positions of stars and apply physical models to try to reproduce these motions.”

“We end up with a measurement of a dark mass extension in the center of the cluster,” Vitral explained. “The stars move more randomly as they get closer to the central mass.” And, as the center mass increases, so do the stellar velocities.”

Because intermediate-mass black holes in globular clusters have been so difficult to find, Vitral warns, “While we cannot completely confirm that it is a central point of gravity, we can show that it is very small.” It’s too little for us to explain anything other than a solitary black hole. Alternatively, there could be a stellar mechanism that we are simply unaware of, at least in terms of present physics.”