Near-Earth objects and close calls

c.a.

The Living Force
FOTCM Member

Snip Corey S. Powell 12-16 minute Read
Where are the most important places to explore in the solar system?

The leading answers to that question have shifted over the years, driven by scientific discoveries, public curiosity, technological realities, and political agendas. For human exploration, the list of plausible destinations has always been short: Earth-orbit and the Moon. (Mars is achievable, no doubt, but we are not at all technologically ready to go there right now.) For robotic probes, the list started in the same place but kept going: inward to Mercury and the Sun itself, outward past Neptune and Pluto.

For the most part, though, we've ignored the other 99.9999 percent of the objects in the inner solar system: the asteroids. There are, by current estimates, nearly two million asteroids more than a kilometer in diameter. Collectively, they represent a landscape greater than the surface of the Moon, but we'd never seen one up close until 1991. Even now, we've visited just a dozen of them. The asteroids didn't get much love.

That's about to change: There currently are nine dedicated asteroid missions underway or in development (ten if you include MMX, a Japanese mission to Mars's inner moon, Phobos, which might be a captured asteroid). Hayabusa2 is about to swing past Earth next week, dropping off samples of asteroid Ryugu over Australia. OSIRIS-REx will follow behind with a larger cache of rocks that it recently collected from another small asteroid, Bennu.

The next round of asteroid missions will try out a bunch of unusual styles of exploration. Lucy will visit the Trojan asteroids that move in the same orbit as Jupiter. The Psyche mission will travel to the asteroid Psyche — a mysterious object that appears to be composed almost entirely of metal. As a bonus, the same rocket that carries Psyche will also launch Janus, two miniature probes that will examine a pair of binary asteroids. DESTINY+ will head to Phaethon, a "rock-comet" asteroid that appears to be crumbling because it passes so close to the Sun. And NEA Scout will use a solar sail to navigate to a near-Earth asteroid.

Most dramatic of all, the DART spacecraft will ram full-speed into a small asteroid Dimorphos in 2022. The goal is to test out a technique for deflecting a dangerous asteroid if we discover one coming our way; four years later, the Hera probe will follow up to assess the damage.

In the fall of 2022, the DART spacecraft will execute a high-speed collision with 160-meter-wide asteroid Dimorphos, seen here orbiting its larger companion, Didymos. (Credit: NASA/Johns Hopkins APL)

In the fall of 2022, the DART spacecraft will execute a high-speed collision with 160-meter-wide asteroid Dimorphos, seen orbiting its larger companion, Didymos. (Credit: NASA/JHU-APL)

It looks like a long-path meteor that flowed at 23:58 on December 4, 2020 was seen with a wide-angle camera from Hiratsuka to the high sky north. It wasn't bright enough to be called a fireball, but it continued to shine even outside the field of view of this camera, shining for nearly 7 seconds. Since Fuji was cloudy, simultaneous observations have not been established.

AMS event #7369-2020
•Dec 5, 2020 (IA and IL on Friday, December 4th 2020 around 09:43)

AMS

Major Showers to come


Hmm, 🤔 there's still some uncertainty of what this claimed sixties era object may be.

Using data collected at NASA’s Infrared Telescope Facility (IRTF) and orbit analysis from the Center for Near-Earth Object Studies (CNEOS) at NASA’s Jet Propulsion Laboratory, scientists have confirmed that Near-Earth Object (NEO) 2020 SO is, in fact, a 1960’s-Era Centaur rocket booster.
The object, discovered in September by astronomers searching for near-Earth asteroids from the NASA-funded Pan-STARRS1 survey telescope on Maui, garnered interest in the planetary science community due to its size and unusual orbit and was studied by observatories around the world.

Further analysis of 2020 SO’s orbit revealed the object had come close to Earth a few times over the decades, with one approach in 1966 bringing it close enough to suggest it may have originated from Earth. Comparing this data with the history of previous NASA missions, Paul Chodas, CNEOS director, concluded 2020 SO could be the Centaur upper stage rocket booster from NASA’s ill-fated 1966 Surveyor 2 mission to the Moon.

Equipped with this knowledge, a team led by Vishnu Reddy, an associate professor and planetary scientist at the Lunar and Planetary Laboratory at the University of Arizona, performed follow up spectroscopy observations of 2020 SO using NASA’s IRTF on Maunakea, Hawai’i.

“Due to extreme faintness of this object following CNEOS prediction it was a challenging object to characterize” said Reddy. “We got color observations with the Large Binocular Telescope or LBT that suggested 2020 SO was not an asteroid.”

Through a series of follow up observations, Reddy and his team analyzed 2020 SO’s composition using NASA’s IRTF and compared the spectrum data from 2020 SO with that of 301 stainless steel, the material Centaur rocket boosters were made of in the 1960’s. While not immediately a perfect match, Reddy and his team persisted, realizing the discrepancy in spectrum data could be a result of analyzing fresh steel in a lab against steel that would have been exposed to the harsh conditions of space weather for 54 years. This led Reddy and his team to do some additional investigation.

“We knew that if we wanted to compare apples to apples, we’d need to try to get spectral data from another Centaur rocket booster that had been in Earth orbit for many years to then see if it better matched 2020 SO’s spectrum,” said Reddy. “Because of the extreme speed at which Earth-orbiting Centaur boosters travel across the sky, we knew it would be extremely difficult to lock on with the IRTF long enough to get a solid and reliable data set.”

However, on the morning of Dec. 1, Reddy and his team pulled off what they thought would be impossible. They observed another Centaur D rocket booster from 1971 launch of a communication satellite that was in Geostationary Transfer Orbit, long enough to get a good spectrum. With this new data, Reddy and his team were able to compare it against 2020 SO and found the spectra to be consistent with each another, thus definitively concluding 2020 SO to also be a Centaur rocket booster.

“This conclusion was the result of a tremendous team effort,” said Reddy. “We were finally able to solve this mystery because of the great work of Pan-STARRS, Paul Chodas and the team at CNEOS, LBT, IRTF, and the observations around the world.”

2020 SO made its closest approach to Earth on Dec. 1, 2020 and will remain within Earth’s sphere of gravitational dominance—a region in space called the “Hill Sphere” that extends roughly 930,000 miles (1.5 million kilometers) from our planet—until it escapes back into a new orbit around the Sun in March 2021. As NASA-funded telescopes survey the skies for asteroids that could pose an impact threat to Earth, the ability to distinguish between natural and artificial objects is valuable as nations continue to explore and more artificial objects find themselves in orbit about the Sun. Astronomers will continue to observe this particular relic from the early Space Age until it’s gone.

For more information about NASA's Planetary Defense Coordination Office, visit: https://www.nasa.gov/planetarydefense
 

sToRmR1dR

The Living Force
FOTCM Member

c.a.

The Living Force
FOTCM Member




AMS event #7444-2020
Location Oswego US Dec 8, 2020
It looks like the fireball that flowed at 1:26 on December 7, 2020 was seen with a wide-angle camera from Hiratsuka to the northern sky. It exploded twice at the end.

藤井大地 @dfuji1
It looks like the fireball that flowed at 1:26 on December 7, 2020 was seen with a wide-angle camera from Hiratsuka to the northern sky. It exploded twice at the end.
 

sToRmR1dR

The Living Force
FOTCM Member
A newly-discovered asteroid flew past Earth at a very close distance.

Posted by Teo Blašković on December 8, 2020
 

c.a.

The Living Force
FOTCM Member
The 11-Jupiter-mass exoplanet called HD106906 b occupies an unlikely orbit around a double star 336 light-years away and it may be offering clues to something that might be much closer to home: a hypothesized distant member of our Solar System dubbed “Planet Nine.” This is the first time that astronomers have been able to measure the motion of a massive Jupiter-like planet that is orbiting very far away from its host stars and visible debris disc.

The exoplanet HD106906 b was discovered in 2013 with the Magellan Telescopes at the Las Campanas Observatory in Chile’s Atacama Desert. However, astronomers did not then know anything about the planet’s orbit. This required something only the Hubble Space Telescope could do: collect very accurate measurements of the vagabond’s motion over 14 years with extraordinary precision.

The exoplanet resides extremely far from its host pair of bright, young stars — more than 730 times the distance of Earth from the Sun. This wide separation made it enormously challenging to determine the 15 000-year-long orbit in such a short time span of Hubble observations. The planet is creeping very slowly along its orbit, given the weak gravitational pull of its very distant parent stars.

The Hubble team behind this new result [1] was surprised to find that the remote world has an extreme orbit that is very inclined, elongated and external to a dusty debris disc that surrounds the exoplanet’s twin host stars. The debris disc itself is very extraordinary, perhaps due to the gravitational tug of the rogue planet. This study was led by Meiji Nguyen of the University of California, Berkeley.

“To highlight why this is weird, we can just look at our own Solar System and see that all of the planets lie roughly in the same plane,” explained Nguyen. “It would be bizarre if, say, Jupiter just happened to be inclined 30 degrees relative to the plane that every other planet orbits in. This raises all sorts of questions about how HD 106906 b ended up so far out on such an inclined orbit.”

The prevailing theory to explain how the exoplanet arrived at such a distant and strangely inclined orbit is that it formed much closer to its stars, about three times the distance that Earth is from the Sun. However, drag within the system’s gas disc caused the planet’s orbit to decay, forcing it to migrate inward toward its stellar hosts. The gravitational forces from the whirling twin stars then kicked it out onto an eccentric orbit that almost threw it out of the system and into the void of interstellar space. Then a star passed very close by to this system, stabilising the exoplanet’s orbit and preventing it from leaving its home system. Candidate passing stars had been previously identified using precise distance and motion measurements from the European Space Agency’s Gaia survey satellite.

This scenario to explain HD106906 b’s bizarre orbit is similar in some ways to what may have caused the hypothetical Planet Nine to end up in the outer reaches of our own Solar System, beyond the Kuiper Belt. Planet Nine could have formed in the inner Solar System and was then kicked out by interactions with Jupiter. However, Jupiter would very likely have flung Planet Nine far beyond Pluto. Passing stars may have stabilised the orbit of the kicked-out planet by pushing the orbit path away from Jupiter and the other planets in the inner Solar System.

“It’s as if we have a time machine for our own Solar System going back 4.6 billion years to see what may have happened when our young Solar System was dynamically active and everything was being jostled around and rearranged,” explained team member Paul Kalas of the University of California, Berkeley.

To date, astronomers have only circumstantial evidence for the existence of Planet Nine. They’ve found a cluster of small celestial bodies beyond Neptune that move in unusual orbits compared to the rest of the Solar System. This configuration, some astronomers think, suggests that these objects were shepherded together by the gravitational pull of a huge, unseen planet. An alternative hypothesis is that there is not one giant perturber, but instead the imbalance is due to the combined gravitational influence of much smaller objects.

“Despite the lack of detection of Planet Nine to date, the orbit of the planet can be inferred based on its effect on the various objects in the outer Solar System,” explained team member Robert De Rosa of the European Southern Observatory in Santiago, Chile who led the study’s analysis. “This suggests that if a planet was indeed responsible for what we observe in the orbits of trans-Neptunian objects it should have an eccentric orbit inclined relative to the plane of the Solar System. This prediction of the orbit of Planet Nine is similar to what we are seeing with HD 106906b."

Scientists using the upcoming NASA/ESA/CSA James Webb Space Telescope plan to get additional data on HD106906 b to better understand the planet’s system. Astronomers want to know where and how the planet formed and whether the planet has its own debris system around it, among other questions.

“There are still a lot of open questions about this system,” added De Rosa. “For example, we do not conclusively know where or how the planet formed. Although we have made the first measurement of orbital motion, there are still large uncertainties on the various orbital parameters. It is likely that both observers and theorists alike will be studying HD 106906 for years to come, unraveling the many mysteries of this remarkable planetary system.”
Notes
[1] The data used in this study were taken as part the following Hubble Space Telescope observing programs GO-10330 (PI: Ford), GO-14670 (PI: Kalas), GO-14241 (PI: Apai) and GO-14241 (PI: Apai).

These results have been published in the Astronomical Journal.

More information

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
The international team of astronomers in this study consists of M. Nguyen, R. De Rosa, and P. Kalas.
 

sToRmR1dR

The Living Force
FOTCM Member
A newly-discovered asteroid will pass close to Earth on December 18, 2020.

Posted by Teo Blašković on December 12, 2020

 

c.a.

The Living Force
FOTCM Member
Gemini meteor shower was very active last night, witnessing numerous sizes and brightness.

Others have noted within the research community of incoming objects from the unknown's, during the Gemini MS 2020.


Quote:
FRIPON confirmed that brightness and frequency of meteors have an inverse exponential relationship (so yes the dinosaurs got really unlucky). #FRIPON cameras catch #meteors brighter than mag -4, up to mag -9. Blue line is exponential.
1607926883219.png
See: https://www.aanda.org/articles/aa/f...r8OgNwSR5hbw5YSY-EfzUhHPINOzLcYgHEguWKSu_Z4-E #spacerocks
Results. Nearly 4000 meteoroids have been detected so far and characterized by FRIPON. The distribution of their orbits appears to be bimodal, with a cometary population and a main belt population. Sporadic meteors amount to about 55% of all meteors. A first estimate of the absolute meteoroid flux (mag < –5; meteoroid size ≥~1 cm) amounts to 1250/yr/106 km2. This value is compatible with previous estimates. Finally, the first meteorite was recovered in Italy (Cavezzo, January 2020) thanks to the PRISMA network, a component of the FRIPON science project.

These are the asteroids to worry about
Nov 30, 2020

Since @AstroHita The systems of the SMART project (Instituto de Astrofísica de Andalucía IAA-CSIC) have recorded the impressive show that the Geminids have offered last night, 1 day before reaching their maximum https://youtu.be/CCKQRGIeADk @LeoAstronomada
 
Last edited:

c.a.

The Living Force
FOTCM Member
The scientific results released a short while ago showed that, coinciding with the peak of the twin meteors, the Emirates Network for Meteor Observation, affiliated to the International Astronomy Center in Abu Dhabi, in cooperation with the agency "NASA", managed to draw an orbit of 936 meteors last night! And this is done by calculating the trigonometry of meteors that were captured by more than one station!

By Mike Wall 19 hours ago
HD 106906 b is interesting for many reasons.
Planet Nine may not be such an oddball after all, if it does indeed exist.

The exotic exoplanet HD 106906 b is an analog of sorts of Planet Nine, the Neptune-size world hypothesized to lurk in the outer reaches of our own solar system, a new study suggests.

HD 106906 b was discovered in 2013. It's about 11 times more massive than Jupiter and lies 336 light-years from Earth, near the double star HD 106906.

Related: When will we find Planet Nine?

The HD 106906 stellar duo is very young — just 15 million years old — and is still surrounded by a dusty debris disk. HD 106906 b apparently emerged from that disk but is now quite removed from it, zooming along high above the disk's plane. In addition, the giant exoplanet currently lies 737 astronomical units (AU) from the double star, about 25 times more distant from the pair than Neptune is from our sun. (One AU is the average Earth-sun distance, which is about 93 million miles, or 150 million kilometers.)

So HD 106906 b is a pretty curious character. Indeed, scientists have been debating whether the alien planet is still a bona fide member of the HD 106906 system or if it's now speeding away from the two stars, having been booted out by a gravitational interaction.

There's evidence that such a booting did take place: photos captured a few years ago by the Gemini South Telescope in Chile show that HD 106906's outer dust disk and inner comet disk are lopsided. HD 106906 b could have done this sculpting if the planet formed close to the system's center and was then kicked outward after a close encounter with the double stars, previous modeling work has indicated.

Such a disturbance would ordinarily send a planet out of its home system entirely, turning it into a "rogue" that wanders the galaxy alone, free of any host star — unless its departure was arrested by another gravitational interaction, this time with a star that wandered close to the HD 106906 system.

Last year, a group that included two of the three authors on the new study identified several stars that could have provided such a nudge about 3 million years ago. And the new paper suggests that one of those interloping stars may indeed have kept HD 106906 b from becoming a runaway.

In the new work, researchers led by Meiji Nguyen, a recent graduate of the University of California, Berkeley, analyzed observations of the HD 106906 system made between 2004 and 2018 by NASA's Hubble Space Telescope. The astronomers also compared the Hubble images with data gathered by Europe's Gaia spacecraft, which is precisely mapping the positions and movements of billions of stars in our Milky Way galaxy.

Related: The evidence for 'Planet Nine' in our solar system (gallery)

These combined data sets allowed the three scientists to nail down the positions of the HD 106906 binary and the giant planet. They found that HD 106906 b is likely in an elliptical and very long — but stable — orbit around its two parent stars, completing one lap every 15,000 years.

"Though it’s only been 14 years of observations, we were still able to, surprisingly, get a constraint on the orbit for the first time, confirming our suspicion that it was very misaligned and also that the planet is on an approximately 15,000-year orbit," Nguyen said in a statement.

"The fact that our results are consistent with predictions is, I think, a strong piece of evidence that this planet is, indeed, bound. In the future, a radial-velocity measurement is needed to confirm our findings," Nguyen added. (Radial-velocity measurements quantify the gravitational tug exerted by planets upon their host stars.)

What does this have to do with Planet Nine? The inferred history of HD 106906 b is similar to that proposed to explain how Planet Nine — or Planet Next, Planet X or Giant Planet Five, for those who will always regard Pluto as our solar system's ninth planet — could have gotten into, and remained in, its putative orbit, a highly elliptical path that keeps it hundreds of AU from the sun.

"What I really think makes HD 106906 b unique is that it is the only exoplanet that we know that is directly imaged, surrounded by a debris disk, misaligned relative to its system and is widely separated," Nguyen said. "This is what makes it the sole candidate we have found thus far whose orbit is analogous to the hypothetical Planet Nine."

The new study was published online this week in The Astronomical Journal. You can read a preprint of it for free at arXiv.org.

Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.

By Robin George Andrews Dec. 3, 2020
As Douglas Adams once said: Space is big. Really big. Consequently, scientists see only tiny slivers of space at any given moment, so on those infrequent occasions when something new is observed, it’s a revelatory delight.

Astronomers recently witnessed an enigmatic icy object in Jupiter’s shadow begin its transformation into a type of comet, one that sticks close to the sun. It’s the first time they’ve watched this happen.

The object, named LD2, is called a Centaur, an icy proto-world named after mythological part-person, part-horse creatures because these orbs can behave like an asteroid and a comet. Centaurs hang out between Jupiter and Neptune. Constantly pulled at by the gravity of the gas and ice giants, they are usually either expunged from the solar system, or they are thrown toward the sun. In that case, they become hyperactive comets, orbiting the sun along a highly elliptical racetrack that doesn’t extend too far beyond Jupiter.

According to a study published last month in The Astrophysical Journal Letters, the chaos of this gravitational battle royale has determined that LD2 is going to set up shop in the inner solar system. Forty-three years from now, this Centaur’s transition will be complete. It will be fizzing and bubbling as it is braised by the sun, becoming the newest member of the so-called Jupiter Family of Comets.

The migration of comets and soggy asteroids from the fringes of our stellar neighborhood toward the rocky inner worlds was like a water delivery service in the early days of the solar system, slaking the thirst of planets drying out because of giant impacts and planetwide magma oceans. LD2’s encroachment will allow astronomers to see what happens when a pristine icy object makes a daring dive toward the sun, providing an enlightening echo of eras past.

Meg Schwamb, an astronomer at Queen’s University Belfast who was not involved with the study, said that scientists tended to get only snapshots of space phenomena. This time, we get to see an entire cosmic process play out from start to end. “We have a front-row seat,” she said. “You can get your popcorn out.”

Many millions of years ago, LD2 was an icy object beyond Neptune’s orbit. The planet’s gravity ensnared it and brought it into the space between Jupiter and Neptune.

In 2019, the Asteroid Terrestrial-impact Last Alert System or ATLAS, a pair of NASA-funded telescopes developed by the University of Hawaii that search for potential city-killing and country-crushing space rocks, spotted an object that appeared to be tracing Jupiter’s orbital path. Astronomers named it P/2019 LD2, or LD2 for short.

On closer inspection, its orbit was found to be suspiciously wobbly. Orbital calculations suggest that it got a bit too close to Jupiter’s massive gravitational force in 2017. Like a cyclist going around a velodrome encountering a sudden steep drop, LD2 was thrown off-balance, putting it on course to fall toward, and ultimately remain mostly within, the inner solar system.

It was also found to be rather excitable: Astronomers could see escaping icy matter forming a hazy cloud called a coma, and a tail rocketed out into the inky beyond. But its coma lacks water vapor, said Teddy Kareta, a planetary astronomy graduate student at the University of Arizona and co-author of the study. Combined with models of its orbital evolution, this suggests LD2 has not yet visited the inner solar system. Scientists caught it just as it started its first journey into the warmer region around our sun.

By 2063, LD2 will be shooting around our local star at breakneck speeds, completing one orbit roughly every six years. Being close enough to the sun, its water ice will be persistently obliterated, fueling a water vapor coma. “And water-driven activity is usually what we think of as a comet,” said Jordan Steckloff, a research scientist at the Planetary Science Institute in Tucson, Ariz., and the study’s lead author.
Considering the epic length of astronomical time scales, LD2’s fleeting saga is unusual. Its evolutionary journey is happening in lock step with our day-to-day existence. A young astronomer can follow its entire transition, from youth to cometary adulthood, and still be alive at its conclusion.

LD2’s ephemerality isn’t lost on scientists. “To see something that’s so short-lived, that’s changing — it’s a reminder that the solar system is dynamic,” Dr. Schwamb said. “It is a changing being, in some sense, just like us.”

2-meter asteroid 2020 XK1 was a team effort. Catalina Sky Survey detected this near-impactor last night, then "handed off" the object to ATLAS-Haleakala, which continued tracking it so that it would not get lost. https://minorplanetcenter.net/mpec/K20/K20X5
3:03 AM · Dec 8, 2020·

Bolide #France#Yonne#Aube the 12/13/2020 at 17:41 CET Photographed by Joachim Kruse from Halver, North Rhine Westphalia #Allemagne


Denis Vida @meteordoc 4:02 PM · Dec 14, 2020
250x timelapse of the peak of the Geminids (1 video frame = ~10 seconds)
https://twitter.com/meteordoc/status/1338499617240064000
 
Last edited:

Bluegazer

The Living Force
FOTCM Member
What Causes the Mass Extinction Cycles? When palaeontologists study extinctions events a very curious pattern appears. We have discussed our motion along twisting birkeland currents both on this channel and on the Thunderbolts. We speculated that the idea of the Nemesis Star and it’s 26 Millions Year extinction may be linked to our motion around the Pleiades. In a new study just published scientists have examined the frequency of extinction events in land animals and found that it coincides with reported mass extinctions of oceans life and points to a cycle of 27 Millions year. Let's examine why this might be a very important finding.

 

sToRmR1dR

The Living Force
FOTCM Member
Top Bottom