Posted on by Nicholos Wethington

Hubble Sees Asteroid Collision in Slow-Motion

The collision between two asteroids in early 2009 produced a strange, X-shaped aftermath. Image Credit: NASA, ESA and D. Jewitt (UCLA)

[/caption]

Alas, the image above is not marking alien pirate treasure in space – for the first time, the aftermath of a collision between two asteroids has been imaged. Last January, an international team of astronomers saw the strange X-shaped object with the Hubble Space Telescope after ground-based observatories spotted evidence of an asteroid collision in the asteroid belt. The team has now used Hubble to do follow-up observations and uncovered a few surprises about the collision.

The collision produced an X shape, followed by a long comet-like tail. The astronomers, led by David Jewitt of the University of California in Los Angeles, were surprised to find that the collision did not happen as recently as they’d thought, but had actually occurred almost a year previous to the detection. It’s likely that the two asteroids smashed together sometime in February or March of 2009.

“When I saw the Hubbble image I knew it was something special,” said ESA astronomer Jessica Agarwal in a press release.

Named P/2010 A2, the object is located in the asteroid belt between Mars and Jupiter. Asteroid collisions are thought to be a commonplace occurrence, and are responsible for kicking up dust in our Solar System and other planetary systems. Just how much dust is produced, and how frequent the collisions happen is still a hazy topic, and the recent observation of P/2010 A2 should help astronomers to better model this phenomenon.

By figuring out how much dust is produced by the process of ‘collisional grinding’, astronomers could better model the dusty debris disks of other planetary systems, as well as our own.

The team monitored the slow-motion expansion of the leftovers of the colliding asteroids with the Hubble Space Telescope between January and May of 2010. They’ve determined that P/2010 A2 is about 120 meters (393 feet) wide, and the particles of dust that make up the tail following it are between 1 millimeter (0.04 inches) to 2.5 centimeters (1 inch) in diameter.

The collision producing the object P/2010 A2, as observed over the course of a few months by Hubble. Image Credit: NASA, ESA and D. Jewitt (UCLA)

The remnants of the collision suggest that a smaller asteroid – 3 to 5 meters (10-16 feet) wide – collided into a larger one at about 18,000 km per hour (11,000 miles per hour). This vaporized the smaller asteroid, and ejected material from the larger one.

Why is the object X-shaped? That mystery has yet to be determined. It is likely, according to the team, that the filaments produced by the collision suggest asymmetries in the colliding objects. Further observations of P/2010 A2 with the Hubble in 2011 will show just how the collision continues to change, allowing for a more precise model of how it started out.

The observed tail is caused by the same mechanism that produces cometary tails – radiation pressure from the Sun pushes the dust away from the nucleus of the object.

As to why we don’t have thousands of Hubble images to produce a whole alphabet of asteroid collisions shapes – “Catching colliding asteroids on camera is difficult because large impacts are rare, while small ones, such as the one that produced P/2010 A2, are exceedingly faint,” Jewitt said. The results of their observations will be published in the October 14th issue of the journal Nature.

Source: ESA Press Release

Posted on by Nancy Atkinson

Video: Asteroid 2010 TD54 Whizzes Close to Earth

A 'movie' put together from images of the October 12, 2010 approach of asteroid 2010 TD54.Image credit: Patrick Wiggins, NASA/JPL Solar System Ambassador to Utah

[/caption]

Amateur astronomer Patrick Wiggins from Utah (and fellow Solar System Ambassador) was able to capture images this morning of the newly found asteroid 2010 TD54 that whizzed by Earth — harmlessly — coming within about 46,000 km (less than 30,000 miles) of our planet. The small asteroid was only detected this past Saturday, and NASA’s Near Earth Object Office predicted there was only 1 in a million chance it would hit Earth, and was small enough that it wouldn’t survive a fiery trip through the atmosphere even if it was going to make crash head-on into Earth. Patrick put together a couple of “movies” from the images he captured. They show the asteroid whispering silently through the sky, although moving along fairly quickly at 17.37 km/s. Estimates are the asteroid is about 7.3 m wide, and contained the energy of about 22 kilotons if it would have come crashing through Earth’s atmosphere. For this animation, the mount was set to allow the target to pass through the field of view, and includes 16 five-second exposures shot between 08:51:51 and 08:54:04 UTC.

There’s an additional image below.

In this animation, asteroid 2010 TD54 appears stationary as the stars move. Image credit: Patrick Wiggins, NASA/JPL Solar System Ambassador to Utah

For this set of images, Patrick set the mount set to nearly follow the target. The animation includes 23 five- second exposures shot between 09:01:27 and 09:04:39 UTC.

Patrick uses a Paramount ME, Celestron C-14 operating at f/5.5, SBIG ST-10 binned 3×3 with clear filter. The field of view in this image is about 18×26 arc minutes.

“The target was rotating quickly during both sequences which is “reflected” (pun intended) by its rapidly changing brightness,” Patrick wrote on a news group webpage for asteroid and comet researchers.

Great work! And Universe Today thanks Patrick for allowing us to post his images/animations.

While most people are breathing a sigh of relief that this asteroid didn’t hit Earth, others are of the opinion this near miss was a missed opportunity. “The message here should be: It was a pity that TD54 *missed* Earth because it would have made a nice fireball and meteorite shower!” said astronomer and writer Daniel Fischer, who writes the Cosmos4U blog.

Other astronomers and meteorite buffs said this asteroid could have ended up like the famous 2008 TC3, the first asteroid to have been spotted before hitting Earth, which crashed in northern Sudan, providing a treasure trove of information about asteroids and the early solar system in a very handy “sample return.”

Posted on by Nancy Atkinson

Breaking News: Small NEO Could Pass Within 60,000 km of Earth on Tuesday

Artists impression of an asteroid flying by Earth. Credit: NASA

[/caption]

A small asteroid will likely pass very close to Earth this week Tuesday. Astronomers are still tracking the object, now designated as 2010 TD54, and various estimates say it could possibly come within anywhere from 52,000 km (33,000 miles) to 64,000 km (40,000 miles) on October 12, with closest approach at approximately 11:25 UT. Information on the IAU Minor Planet Center website lists the object as coming with 0.0003 AU. The size of the object has not been determined, but estimates say it is likely smaller than 10 meters. We’ll provide an update as soon as more information is available.

UPDATE: Don Yeomans, Manager of NASA’s Near-Earth Object Program Office replied to an inquiry about the object and said the newly discovered NEO 2010 TD54 is approximately 5-10 meters in size, and is now predicted to pass about 46,000 km from Earth’s surface at about 07:25 EDT (11:25 UT) on Tuesday, Oct 12, 2010. It was discovered by Catalina Sky Survey on Saturday morning.

“Only 1 in a million chance of an impact,” Yeomans said, “and even if it does impact, it is not large enough to make it through the Earth’s atmosphere to cause ground damage.”

The object may be visible to amateur telescopes as a 14th magnitude “star” — it will be traveling through the constellations Pisces and Aquarius.

Sources: IAU Minor Planet Center, Unmanned Spaceflight,Yahoo News Groups

Posted on by Nancy Atkinson

Water Ice Found on Another Asteroid

Artists concept of an asteroid around a planetary body. Credit: Gabriel Pérez, Instituto de Astrofisica de Canarias, Spain

[/caption]

There could be a lot more water out there than anyone thought. A second asteroid has been found to contain water ice. In April of this year, water ice and organics was found on 24 Themis, a 200-kilometer wide asteroid. Now, the two teams of researchers made who made the first discovery have now found the same materials on asteroid 65 Cybele.

“This discovery suggests that this region of our solar system contains more water ice than anticipated,” said University of Central Florida Professor Humberto Campins. “And it supports the theory that asteroids may have hit Earth and brought our planet its water and the building blocks for life to form and evolve here.”

Asteroid 65 Cybele is somewhat larger than asteroid 24 Themis, with a diameter of 290 km (180 miles). Both asteroids are located in the asteroid belt that sits halfway between Mars and Jupiter.

Generally, asteroids were thought to be very dry, but it now appears that when the asteroids and planets were first forming in the very early Solar System, ice extended far into the Main Belt region, which could mean water and organics may be more common near each star‘s habitable zone.

See our article from yesterday about molecules of life’s building blocks in Titan’s atmosphere and how it could add a third way for life to spring up on a planet (one being asteroid delivery, two being rising from the primordial soup thought to exist on early Earth).

The team’s paper will be published in the European Journal “Astronomy and Astrophysics,” and Campins presented his findings at the American Astronomical Society’s Division of Planetary Sciences meeting this week.

Source: University of Central Florida

Posted on by Nancy Atkinson

JAXA: Hayabusa Capsule Contains Particles, Maybe of Asteroid

Artist concept of the Hayabusa spacecraft, which visited asteroid Itokawa in 2005 and returned samples to Earth in 2010. Credit: JAXA
Artist concept of the Hayabusa spacecraft, which visited asteroid Itokawa in 2005 and returned samples to Earth in 2010. Credit: JAXA

[/caption]

At a press conference yesterday, officials from the Japan Aerospace Exploration Agency (JAXA) announced that they had “scraped up” a hundred or so particles of dust, perhaps grains of dust from the asteroid, Itokawa, inside the sample return capsule of the Hayabusa spacecraft. This is great news, as previous reports from JAXA indicated they weren’t sure if there were any particles at all inside the container. Originally, the mission had hoped to bring back “peanut-sized” asteroid samples, but the device that was supposed to fire pellets at the asteroid may not have worked, and for a time, scientists were even unsure if the spacecraft had even touched down on the asteroid.

During the seven-year round trip journey, Hayabusa arrived at Itokawa in November, 2005. After a circuitous and troubled-filled return trip home, the sample return capsule was ejected and landed in Australia in June of this year.

The 100 or so grains reported yesterday are extremely tiny, and the micron-sized particles were scraped off the sides of container and are now being examined with an electron microscope. They don’t appear to be metallic, so are not fragments from the container, but they don’t have absolute proof yet that the particles are from the asteroid.

Soon, the grains will be examined using particle accelerator/synchrotron. Additionally, some reports indicated there is another yet unopened compartment that will be examined soon.

A little surfing of the net (in all languages) reveals there are tons of news articles out there reporting this. The only problem is that some of these news reports called the potential asteroid particles “extraterrestrial,” which then became translated as “extraterrestrial life” in the next article in another language. Ah, the wonders of the internet!

We’ll keep you posted!

Posted on by Jon Voisey

Trojans May Yet Rain Down

It would be an interesting survey to catalog the initial reactions readers have to “Trojans”. Do you think first of wooden horses, or do asteroids spring to mind? Given the context of this website, I’d hope it’s the latter. If so, you’re thinking along the right lines. But how much do you really know about astronomical Trojans?

While most frequently used to discuss the set of objects in Jupiter’s orbital path that lie 60º ahead and behind the planet, orbiting the L4 and L5 Lagrange points, the term can be expanded to include any family of objects orbiting these points of relative stability around any other object. While Jupiter’s Trojan family is known to include over 3,000 objects, other solar system objects have been discovered with families of their own. Even one of Saturn’s moons, Tethys, has objects in its Lagrange points (although in this case, the objects are full moons in their own right: Calypso and Telesto).

In the past decade Neptunian Trojans have been discovered. By the end of this summer, six have been confirmed. Yet despite this small sample, these objects have some unexpected properties and may outnumber the number of asteroids in the main belt by an order of magnitude. However, they aren’t permanent and a paper published in the July issue of the International Journal of Astrobiology suggests that these reservoirs may produce many of the short period comets we see and “contribute a significant fraction of the impact hazard to the Earth.”

The origin of short period comets is an unusual one. While the sources of near Earth asteroids and long period comets have been well established, short period comets parent locations have been harder to pin down. Many have orbits with aphelions in the outer solar system, well past Neptune. This led to the independent prediction of a source of bodies in the far reaches by Edgeworth (1943) and Kuiper (1951). Yet others have aphelions well within the solar system. While some of this could be attributed to loss of energy from close passes to planets, it did not sufficiently account for the full number and astronomers began searching for other sources.

In 2006, J. Horner and N. Evans demonstrated the potential for objects from the outer solar system to be captured by the Jovian planets. In that paper, Horner and Evans considered the longevity of the stability of such captures for Jupiter Trojans. The two found that these objects were stable for billions of years but could eventually leak out. This would provide a storing of potential comets to help account for some of the oddities.

However, the Jupiter population is dynamically “cold” and does not contain a large distribution of velocities that would lead to more rapid shedding. Similarly, Saturn’s Trojan family was not found to be excited and was estimated to have a half life of ~2.5 billion years. One of the oddities of the Neptunian Trojans is that those few discovered thus far have tended to have high inclinations. This indicates that this family may be more dynamically excited, or “hotter” than that of other families, leading to a faster rate of shedding. Even with this realization, the full picture may not yet be clear given that searches for Trojans concentrate on the ecliptic and would likely miss additional members at higher inclinations, thus biasing surveys towards lower inclinations.

To assess the dangers of this excited population, Horner teamed with Patryk Lykawka to simulate the Neptunian Trojan system. From it, they estimated the family had a half life of ~550 million years. Objects leaving this population would then undergo several possible fates. In many cases, they resembled the Centaur class of objects with low eccentricities and with perihelion near Jupiter and aphelion near Neptune. Others picked up energy from other gas giants and were ejected from the solar system, and yet others became short period comets with aphelions near Jupiter.

Given the ability for this the Neptunian Trojans to eject members frequently, the two examined how many of the of short period comets we see may be from these reservoirs. Given the unknown nature of how large these stores are, the authors estimated that they could contribute as little as 3%. But if the populations are as large as some estimates have indicated, they would be sufficient to supply the entire collection of short period comets. Undoubtedly, the truth lies somewhere in between, but should it lie towards the upper end, the Neptunian Trojans could supply us with a new comet every 100 years on average.

Posted on by Nicholos Wethington

Rosetta Uncovers a Thick, Dusty Blanket on Lutetia

An image taken by the Rosetta spacecraft on its closest approach to 21-Lutetia in July. Recent analysis of the data shows a thick, dusty blanket coating the asteroid. Image Credit:ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

[/caption]

If you think that asteroids are boring, unchanging rocks floating in space waiting only to crop up in bad science fiction films, think again. Images and data that are being returned from various asteroid flybys – such as those by the Rosetta spacecraft and Hayabusa sample return mission – show that asteroids are dynamic, changing miniature worlds unto themselves.

During the recent flyby of the asteroid 21-Lutetia in July, the ESA’s Rosetta spacecraft took an amazing amount of data. After combing through all of this data over the past few months, astronomers have calculated that the asteroid is covered in a 2000-foot (600 meter)-thick blanket of rocks and dust called regolith. This dust is not unlike the outer layer of the Earth’s Moon, consisting of pulverized material that has accumulated over billions of years.

Rosetta is on a course to meet up with the comet 67P/Churyumov-Gerasimenko in 2014, but the spacecraft is no stranger to asteroid visits – on September 6th, 2008, Rosetta made its closest approach of the asteroid 2867-Steins. During this brief visit, Rosetta came within 500 miles (800km) of the small, diamond-shaped asteroid. Among the discoveries made were a chain of impact craters that were likely caused by the collision with a meteoroid stream, or the impact with another small body.

It then approached 21-Lutetia on July 10th of 2010, monitoring the asteroid with 17 instruments on board the spacecraft.

Rosetta took a number of images of the flyby, as well as examining the asteroid with electromagnetic detectors that covered the gamut from the UV to radio waves. Here’s a short animation showing the flyby:

Dr. Rita Schulz from the ESA Research and Scientific Support Department in the Netherlands presented this new information about 21-Lutetia’s regolith today at the Division for Planetary Sciences meeting in Pasadena, CA. She said that the regolith on the asteroid has been determined to be about 2000 feet (600 meters) thick, and that it resembles the regolith on the Moon. Images from the flyby reveal landslides, boulders, ridges, and other kinds of different geologic (or asterologic?) features.

21-Lutetia was determined by the July flyby to have a large, bowl-shaped impact crater on its surface, as well as an abundance of smaller craters. The thick covering of dust “softens” the sharper edges of impact craters in many of the images taken. Whether or not most asteroids of this size are covered in a similar blanket of material remains to be seen.

Boulders can be seen in this close-up image of 21-Lutetia, as taken by Rosetta during the July flyby. Image Credit: mage credit: ESA 2010 MPS for OSIRIS Team MPS/UPD/LAM/IAA/RSSD/INTA/UPM/DASP/IDA

In understanding more about asteroids and comets, astronomers are better able to hone their model of how our Solar System formed. By studying the composition and frequency of impacts of various asteroids, they can improve their data of just how things have changed since the primordial Solar System.

You can bet your boulders that Rosetta isn’t the only spacecraft to be making multiple rendezvous missions with the smaller denizens of our Solar System. Close flybys, impacts and landings on asteroids and comets are becoming almost commonplace for spacecraft.

There’s the Deep Impact mission, which slammed a huge copper weight into the comet Tempel 1, and has since been renamed EPOXI and is set to approach the comet Hartley 2. The upcoming approach of Vesta and Ceres by the Dawn mission is very much anticipated, and of course the recent success of the Hayabusa asteroid explorer has been a terrific tale of just how much we stand to learn from the trail of small celestial cairns that lead into our past.

Source: ESA, DPS Press Release

Posted on by Jon Voisey

Does a “Rock Comet” Generate the Geminids?

Meteor
Geminid meteor shower

[/caption]

Many annual meteor showers have parent bodies identified. For example, the Perseids are ejecta from the comet, Swift-Tuttle and the Leonids from Tempel-Tuttle. Most known parent bodies are active comets, but one exception is the Geminid meteor shower that peaks in mid December. The parent for this shower is 3200 Phaethon. Observations of this object have shown it to be largely inactive pegging it as either a dead comet or an asteroid. But on June 20, 2009, shortly after perihelion, 3200 Phaethon brightened by over two magnitudes indicating this object may not be as dead as previously considered. A new paper considers the causes of the brightening and concludes that it could be a new mechanism leading to what the authors deem a “rock comet”.

David Jewett and Jing Li of UCLA, the authors of this new paper, consider several potential causes. Due to the size of 3200 Phaethon, they suggest that a collision is unlikely. One clue to the reason for the sudden change in brightness was a close link of a half of a day to a brightening in the solar corona. Given a typical solar wind speed and the distance of 3200 Phaethon at the time, this would put the Geminid parent just at the right range to be feeling the effects of the increase. However, the authors conclude that this cannot be directly responsible by imparting sufficient energy on the surface of the object to cause it to fluoresce due to an insufficient solar wind flux at that distance.

Instead, Jewett and Li consider more indirect explanations. Due to the temperature at 3200 Phaethon’s perihelion (0.14 AU) the presence of ices and other volatile gasses frozen solid and then blasting away as often happens in comets was ruled out as they would have been depleted on earlier orbits. However, the blow from the increased solar wind may have been sufficient to blow off loosely bound dust particles. While this is plausible, the authors note that the amount of mass lost if this were the case would be a paltry 2.5 x 108 kg. While it’s possible that this may have been the cause of this single brightening, this amount of mass loss to the overall stream of particles responsible for the Geminid shower would be insufficient to sustain the stream and similar losses would have to occur ~10 times per orbit of the body. Since this has not been observed, it is unlikely that this event was tied to the production of the meteors. Additionally, it is somewhat unlikely that it could even be the event for this sole case since repeated perihelions would slowly deplete the reservoir of available dust until the body was left with only a bare surface. Unlike active comets which continually free dust to be ejected through sublimation of ice, 3200 Phaethon has no such process. Or does it?

The novel proposition is that this object may have an unusual mechanism by which to continually generate and liberate dust particles of the size of the Geminids. The authors propose that the heating at perihelion causes portions of the rock to decompose. This process is greatly enhanced if the rock has water molecules bonded to it and lab experiments have shown that this can lead to violent fracturing. Such processes, if present, could easily lead to the production of new dust particles that would be liberated during close approach to the sun. This would make this object a “rock comet” in which the properties of a comet’s dust ejection via gasses would be carried out by rocks.

To confirm this hypothesis, future observations would be needed to search for subsequent brightening at perihelion. Similarly, it should be expected that such a process may make a faint cometary tail with only a dust component that may be visible as well, although the lack of any such detection so far, despite studies looking for cometary tails, casts some doubt on this process.

Posted on by Jon Voisey

Follow-up Studies on June 3rd Jupiter Impact

Color image of impact on Jupiter on June 3, 2010. Credit: Anthony Wesley

[/caption]

Poor Jupiter just can’t seem to catch a break. Ever since 1994, when our largest planet was hit by Comet Shoemaker-Levy, detections of impacts on Jupiter have occurred with increasing regularity. Most recently, an impact was witnessed on August 20. On June 3rd of 2010, (coincidentally the same day pictures from Hubble were released from a 2009 impact) Jupiter was hit yet again. Shortly after the June 3rd impact, several other telescopes joined the observing.

A paper to appear in the October issue of The Astrophysical Journal Letters discusses the science that has been gained from these observations.

The June 3rd impact was novel in several respects. It was the first unexpected impact that was reported from two independent locations simultaneously. Both discoverers were observing Jupiter with aims of engaging in a bit of astrophotography. Their cameras were both set to take a series of quick images, each lasting a fifth to a tenth of a second. This short time duration is the first time astronomers have had the ability to recreate the light curve for the meteor. Additionally, both observers were using different filters (one red and one blue) allowing for exploration of the color distribution.

Analysis of the light curve revealed that the flash lasted nearly two seconds and was not symmetric; The decay in brightness occurred faster than the increase at onset. Additionally, the curve showed several distinct “bumps” which indicated a flickering that is commonly seen on meteors on Earth.

The light released in the burning up of the object was used to estimate the total energy-released and in turn the mass of the object.  The total energy released was estimated to be between roughly (1.0–4.0) × 1015 Joules (or 250–1000 kilotons).

Follow-up observations from Hubble three days later revealed no scars from the impact. In the July 2009 impact, a hole punched in the clouds remained for several days. This indicated the object in the June 3 impact was considerably smaller and burned up before it was able to reach the visible cloud decks.

Observations intended to find debris came up empty. Infrared observations showed that no thermal signature was left even as little as 18 hours following the discovery.

Assuming that the object was an asteroid with a relative speed of ~60 km/sec and a density of ~2 g/cm3, the team estimated the size of the object to be between 8 and 13 meters, similar to the size of the two asteroids that recently passed Earth. This represents the smallest meteor yet observed on Jupiter. An object of similar size was estimated to be responsible for the impact on Earth in 1994 near the Marshall Islands. Estimates “predict objects of this size to collide with our planet every 6–15 years” with significantly higher rates on Jupiter ranging from one to one hundred such events annually.

Clearly, amateur observations led to some fantastic science. Modest telescopes, “in the range 15–20 cm in diameter equipped with webcams and video recorders” can easily allow for excellent coverage of Jupiter and continued observation could help in determining the impact rate and lead to a better understanding of the population of such small bodies in the outer solar system.

Posted on by Jon Voisey

Two New Asteroids to Pass Earth This Week

Orbits of 2010 RF12 and 2010 RX30

[/caption]

Two newly discovered asteroids will pass the Earth this week. The asteroids were discovered on September 5th of this year by Andrea Boattini using the 1.5 metre reflector at Mount Lemmon in Arizona as part of the Mount Lemmon Survey.

These two new asteroids have been given the designations of 2010 RF12 and 2010 RX30. Both are small bodies, which is why they were not discovered until mere days before they would pass the Earth. Estimates put the size of RF12 at 5 – 15 meters with a best estimate being around 8 meters (26 ft). The larger, RX30 is estimated to be 12 meters (39 ft), but the range of estimates go from 7 – 25.

Due to the large range of estimates on sizes, as well as poorly constrained relative velocities and an unknown composition, it would be difficult to predict the damage an impact from these bodies could cause. The majority of the mass for such small objects would burn up in the atmosphere with only small fragments surviving to the ground. For comparison, the estimated size of the object that caused the Tunguska event was estimated to be at least a few tens of meters in diameter at the point it exploded in the atmosphere some few miles up. Since the diameter helps to determine the volume, and thus the mass and kinetic energy, this factor increases the potential damage rapidly. However, although the bodies were just discovered this week, their orbits have already been well established for the near future and neither will collide with Earth. Both are rated at a 0 on the Torino scale (data from NASA’s NEO Program for RF12 and RX30 can be seen here and here respectively).

Although both objects will pass closer to the Earth than the moon, due to their small size, neither will be visible to the naked eye. 2010 RF12 is expected to pass the Earth at 21% of the Earth-moon distance and at maximum brightness, reach only 14th magnitude, which is just over 600 times too faint to see with the unaided eye. RX30 will approach at 66% of the Earth-moon distance and is expected to reach a similar peak magnitude. For those interested in tracking or photographing these objects, the Fawkes Telescope Project has created a page dedicated to these two objects, including best exposure times and filters for cameras that can be found here. Ephemeris for RF12 and RX30 can be found here and here respectively.

Although both of these asteroids were discovered on the same day and will be approaching near the same time, their orbits do not appear to be related. RF12’s orbit extends from 0.82 to 1.17 AU and it orbits the Sun once every year. Predictions have shown it only passes near the Earth once every one hundred years. Initially, RX30 was thought to be rotate extremely fast, but revised observations have shown that it takes at least 6 hours to rotate about its axis.