Announcing Asteroid 158092 Frasercain

Asteroid Frasercain

[/caption]

Well, I’ve just been accepted into an elite club of people with astronomical objects named after them. And no, my Mom didn’t name a star after me. The asteroid hunting team of David Healy and Jeff Medkeff have collectively discovered 487 asteroids, and designated 62 of them. You might already recognize some of asteroid names: Philplait, Paulmyers, Rebeccawatson, and Derekcolanduno.

At the end of August I received an email from David Healy notifying me that I was a new member of the asteroid club.

Asteroid 158092 Frasercain was officially designated on August 21, 2008. You can see the full list of named asteroids here – scroll down to see Frasercain. And you can see its current position in the Solar System here.

Those of you who know Jeff Medkeff will know the sad part of this story. Jeff, aka “The Blue Collar Scientist”, passed away on August 3rd from complications with liver cancer – he was 39. I’ve got to be honest and tell you that I didn’t know Jeff. We clearly ran in similar circles, but it wasn’t until Phil, Pamela and other people in the space blogging community informed me of his death that I found and read through his blog; I really wish I’d found it earlier.

If you haven’t already, please visit the Blue Collar Scientist blog. And you can read a very moving blog entry fulfilling Jeff’s last request.

So to Jeff and David, thank you very much for this incredible honour – I promise this won’t go to my head… much.

Rosetta Flies By ‘Diamond in the Sky’ Steins

Mosaic of images from Rosetta's fly by. Credit: ESA

[/caption]

ESA’s Rosetta spacecraft successfully flew by the asteroid 2867 Steins, coming within 800 km (500 miles) and gathering images and data on the irregularly shaped rock in space. “Steins looks like a diamond in the sky,” said Uwe Keller, Principal Investigator for the OSIRIS imaging system on board the spacecraft. Watch a movie of the flyby here. Visible in the images are several small craters on the asteroid, and two huge ones. While the wide-angle camera worked perfectly during the flyby, the narrower and higher resolution camera switched itself off and into safe mode a few minutes before closest approach, but switched back on after a few hours. “The software switched off automatically,” said Gerhard Schwehm, Rosetta mission manager. “The camera has some software limits and we’ll analyze why this happened later.”

Rita Schulz, Rosetta Project Scientist, said, “In the images is a chain of impact craters, which must have formed from recurring impact as the asteroid rotated. The impact may have been caused by a meteoroid stream, or fragments from a shattered small body.”

The chain is composed of about 7 craters. To determine the age of the asteroid, a count of the craters on the asteroid’s surface has been started (the more the number of craters, the older the asteroid). So far, 23 craters have been spotted.

Steins in 3 D.  Credit:  ESA
Steins in 3 D. Credit: ESA

From the images, scientists will try and understand why the asteroid is unusually bright, and how fine grains of the surface regolith are. This will tell them more about how the asteroid formed. Images from the narrow angle camera are yet to be retrieved, and will help add to the knowledge of the surface composition and mineralogy.

“It looks like a typical asteroid, but it is really fascinating how much we can learn from just the images,” said Schwehm. “This is our first science highlight; we certainly have a lot of promising science ahead of us. I’m already looking forward to encountering our next diamond in the sky, the much bigger Lutetia.” Rosetta will meet up with asteroid (21) Lutetia on June 10, 2010.

What’s next for Rosetta? It will reach the maximum distance from the Sun on its current orbit on the 17th of December (2.26 AU) to head back to Earth for the next and last swing-by on the Nov. 13, 2009. After it flies by Lutetia, its final destination is going into orbit around Comet 67P/Churyumov-Gerasimenko in 2014.

Source: ESA

Asteroid Imposters

Are some asteroid masked of their true identity?

[/caption]

A frequent plot device in the old “Mission: Impossible” television show was the special masks the IMF team used so they could impersonate anyone. Viewers were often surprised to find out who ended up being an imposter. Similarly, astronomers and planetary scientists are considering that a fair amount of Near Earth Objects (NEOs) aren’t what they appear: they could be comets impersonating asteroids. Paul Abell, from the Planetary Science Institute says between five and ten percent of NEOs could be comets that are being mistaken for asteroids, and Abell is working on ways to make unmasking them a mission that’s possible.

Some NEOs could be dying comets, those that have lost most of the volatile materials that create their characteristic tails. Others could be dormant and might again display comet-like features after colliding with another object, said Abell. He is using NASA’s Infrared Telescope Facility at the Mauna Kea Observatories in Hawaii and the MMT telescope on Mount Hopkins, south of Tucson, Ariz., to uncover observational signatures that separate extinct/dormant comets from near-Earth asteroids.

This is important for a couple of reasons. First, dormant comets in near-Earth space could become supply depots to support future exploration activities with water and other materials. Second, like other NEOs, they could pose a threat to Earth if they are on a collision course with our planet. Third, they can provide data on the composition and early evolution of the solar system because they are thought to contain unmodified remnants of the primordial materials that formed the solar system.
Comet Tempel 1.  Credit:  NASA/U of Maryland
Unlike rocky asteroids that blast out craters when they slam into Earth, comets are structurally weak and likely to break up as they enter the atmosphere, leading to a heat and shockwave blast that would be much more devastating than the impact from an asteroid of the same size.

Low-activity, near-earth comets flashed onto the planetary-science radar screen in 2001, when NEO 2001 OG108 was discovered by the Lowell Observatory Near Earth Asteroid Search telescope. It had an orbit similar to comets coming in from the Oort Cloud, but had no cometary tail. But in early 2002 when it came closer to the sun, the heat vaporized some of the comet’s ice to create the clouds of dust and gas that make up the comet’s coma and tail. It was then reclassified as a comet.

“That’s what started me on this line of reasoning and scientific investigation,” Abell said.
By combining orbital data with spectra and the albedos (brightness) of these objects, Abell hopes to identify which are low-activity comets and where they are coming from.
“Are all these comets made of the same type of material or are they different?” Abell asked. “If they’re composed of different materials, they may have different spectral signatures, and our preliminary work on Jupiter-family comets and Halley-type comets shows that this may be true. Why is that? Is it something to do with the initial conditions of their formation regions? Or is it due to the different environments in which they spend most of their time?”

“All this is important to understanding their internal makeup, which will give us data on the material composition and evolution of the early solar system,” he added.

Source: PSI Press Release

Countdown to Asteroid Flyby

Artist impression of Rosetta and Asteroid 2867 Steins. Credit: ESA

[/caption]

Time critical is approaching for the Rosetta spacecraft and it’s flyby of the asteroid 2867 Steins. Closest approach is expected on September 5, at 20:58 CEST, (Central European Summer Time), 2:58 pm EDT (US Eastern Daylight Time). To help the public follow the flyby, the Rosetta team now has a blog available, and a timeline has also been posted. At the time of closest approach, Rosetta is planned to be 800 km from the asteroid, passing by at a speed of 8.6 km/s relative to Steins. Both Rosetta and Steins will be illuminated by the Sun, providing an excellent opportunity for science observations.

Although most scientific observations will take place in the few hours around closest approach, several instruments will be switched on for a longer time around the event.

Between 40 and 20 minutes before closest approach, Rosetta will be flipped and the spacecraft will switch to a specially designed asteroid fly-by mode, an optimal configuration that supports the intensive observation and tracking activity of the on-board instruments. The first images and results will be available for presentation to the media during a press conference on Saturday, September 6 at 12:00 CEST.

Asteroid Steins orbit.  Credit:  ESA
Asteroid Steins orbit. Credit: ESA

The timeline is as follows (more details are available in the Rosetta Blog — all times CEST (Central European Summer Time):

1 September
02:20 Instruments switched on (except OSIRIS which was already on for the navigation campaign)

4 September
07:20-11:20 Slot for possible trajectory correction manoeuvre (36 hours before closest approach)
13:20-18:20 Last opportunity to acquire images for optical navigation campaign

5 September
07:20-10:20 Slot for possible trajectory correction manoeuvre (12 hours before closest approach)
10:20 Navigation cameras switch to tracking mode – initially both used, then use CAM ‘A’ only (to be decided)
11:00 Uplink fly-by commands for asteroid fly-by mode (AFM)
Includes an update to the command profile already on board & the final updated AFM commands (only if 1 CAM at least is tracking)
20:18-20:38 Spacecraft flip over
20:39 Spacecraft switches automatically to asteroid fly-by mode
20:56 Sun illuminates Rosetta from the back and the asteroid fully
20:58 Closest approach, at a planned distance of 800 km from the asteroid
22:27 First post-fly-by acquisition of signal (AOS) – telemetry received via NASA’s Goldstone ground station
22:30 Start of science data download via Goldstone

6 September
12:00 Live streaming of Rosetta Steins fly-by press conference from the European Space Operations Centre begins
13:00 Images from fly-by published on ESA web
15:00 End of press conference streaming
16:01 End of reception of first set of science data

News Source: ESA

How To Save the World From Asteroid Impact: Plastic Wrap

Artist's conception shows the Near Earth Asteroid Rendezvous (NEAR) spacecraft orbiting an asteroid. credit: NASA

[/caption]

Remember a competition we reported on back in April called “Move An Asteroid”? It was an international technical paper competition looking for unique and innovative concepts for how to deflect an asteroid or comet that might be on a collision course for Earth. The winners have been announced and first prize went to Australian PhD student Mary D’Souza who came up with quite a novel concept: wrap the asteroid with reflective sheeting. Such a coating may increase the asteroid’s reflectivity, enabling deflection by solar radiation pressure.

The asteroid in question, known as Apophis, will pass close to Earth in 2029. Although the 207 meter- wide Apophis is not expected to impact Earth, its current trajectory has it approaching Earth no closer than 29,470 km (18,300 miles), which is well inside the orbit of the moon. This, in conjuction with the 100th anniversary of the Tunguska explosion, was the impetus behind the competition.

D’Souza’s paper was titled “A Body Solar Sail Concept for the Deflection of 99942 Apophis.” Her concept involves using a satellite orbiting Apophis to wrap it with ribbons of reflective Mylar sheeting. Covering just half of the asteroid would change its surface from dull to reflective, possibly enough to allow solar pressure to change the asteroid’s trajectory.

“What happens then is light from the sun shines on the body [of the asteroid] so more of it is reflected … and it actually acts to move it away from the sun and the earth,” said D’Souza, a student at University of Queensland’s School of Engineering.

The competition was sponsored by the Space Generation Advisory Council, a group representing youth perspectives on space exploration to the United Nations and national space programs. SGAC said they received submissions to the competition from all over the world. “It is great to see such an interest in this topic from young people all over the world. Hopefully with competitions like this, SGAC can further increase the involvement of youth in this important field of current space research,” said Alex Karl, Co-Chairperson of the SGAC.

By winning the competition, D’Souza will travel to Glasgow at the end of September to present her plan at the International Astronautical Congress.

Second place was awarded to Andrew Bacon of the Department of Electronic and Electrical Engineering at the University of Bath for his paper entitled “The Use of Electromechanical Resonators for the Mitigation of Earth Threatening Asteroids and Comets.” Bacon’s concept involves the use of electromechanical resonators to build up waves within an asteroid or comet that would break it up. He will also present his plan at the IAC.

Sources: Space Generation press release, The Register

Rosetta Prepares for Meet-Up With Asteroid Next Week

Asteroid Steins imaged by Rosetta's OSIRIS camera in two locations.

[/caption]

ESA’s Rosetta spacecraft will make an historic encounter with asteroid (2867) Steins on September 5, 2008 at 20:58 CEST (Central European Summer Time), 2:58 pm EDT (US Eastern Daylight Time.) A few days ago, Rosetta conducted a successful trajectory correction maneuver using images from the spacecraft’s cameras to calculate the asteroid’s location, to optimize its trajectory for the fly-by. Rosetta will rendezvous with the asteroid while one its way to its primary mission, to visit comet 67/P Churyumov-Gerasimenko. At its closest approach to the asteroid, the spacecraft will be just 800 km from Steins.

At closest approach, however, the spacecraft will not be in communication with Earth. First ground contact with the spacecraft to verify a successful flyby will occur about an hour and half after the encounter. The first images and results will be available for presentation to the media during a press conference on Saturday, September 6 at 12:00 CEST.

Artist's impression of Rosetta and Asteroid Steins.  Credit:  ESA
Artist's impression of Rosetta and Asteroid Steins. Credit: ESA

Click here for an animation of Rosetta’s flyby.

Steins is Rosetta’s first nominal scientific target. The study of asteroids is extremely important as they represent a sample of Solar System material at different stages of evolution – key to understanding the origin of our own planet and of our planetary neighborhood. Rosetta will also encounter (21) Lutetia on June 10, 2010.

We’ll post the images and information from the flyby here on Universe Today as soon as they are available.

Source: ESA

Solving the Asteroid – Meteorite Puzzle

Meteorites. Credit: NASA

[/caption]

Astronomers studying ways to deal with incoming near-Earth asteroids (NEA) that might be on a collision course with our planet want to know in detail what these space rocks are made of. The better they “know the enemy” the better they can come up with ways to destroy or change the course of NEAs. Since we’ve only studied a couple of asteroids up close with spacecraft, the best way to learn more about the composition of asteroids should be fairly easy: just look at meteorites that fall to Earth, which are small chunks of asteroids. But in doing so, researchers discovered quite a huge discrepancy. The vast majority of asteroids that whiz by Earth are of a type that matches only a tiny fraction of the meteorites that most frequently hit our planet. This difference has had astronomer scratching their heads. But a team of researchers has now found what it believes is the answer to the puzzle. The smaller rocks that most often fall to Earth, it seems, come straight in from the main asteroid belt out between Mars and Jupiter, rather than from the near-Earth asteroid population.

The researchers studied the spectral signatures of near-Earth asteroids and compared them with spectra obtained on Earth from the thousands of meteorites found on Earth. But the more they looked, the more they found that most NEAs — about two-thirds of them — match a specific type of meteorites called LL chondrites, which only represent about 8 percent of meteorites.

“Why do we see a difference between the objects hitting the ground and the big objects whizzing by?” asked Richard Binzel, a professor from MIT. “It’s been a headscratcher.” As the effect became gradually more and more noticeable as more asteroids were analyzed, “we finally had a big enough data set that the statistics demanded an answer. It could no longer be just a coincidence.”

Way out in the main belt, the population is much more varied, and approximates the mix of types that is found among meteorites. But why would the things that most frequently hit us match this distant population better than it matches the stuff that’s right in our neighborhood?

An obscure effect that was discovered long ago was recently recognized as a significant factor in moving asteroids around and putting them on a fast track towards the inner solar system, called the Yarkovsky effect.

This effect causes asteroids to change their orbits as a result of the way they absorb the sun’s heat on one side and radiate it back later as they rotate around, which alters the object’s path. This effect acts much more strongly on the smallest objects, and only weakly on the larger ones.

So, for smaller sized space rocks– the kinds of things that end up as typical meteorites — the Yarkovsky effect plays a major role, moving them with ease from throughout the asteroid belt on to paths that can head toward Earth. For larger asteroids a kilometer or so across, the kind that we worry about as potential threats to the Earth, the effect is so weak it can only move them small amounts.

The new study is also good news for protecting the planet. One of the biggest problems in figuring out how to deal with an approaching asteroid, if and when one is discovered on a potential collision course, is that they are so varied. The best way of dealing with one kind might not work on another.

But now that this analysis has shown that the majority of near-Earth asteroids are of this specific type — stony objects, rich in the mineral olivine and poor in iron — it’s possible to concentrate most planning on dealing with that kind of object, Binzel says. “Odds are, an object we might have to deal with would be like an LL chondrite, and thanks to our samples in the laboratory, we can measure its properties in detail,” he says. “It’s the first step toward ‘know thy enemy’.”

News Source: MIT

Rosetta Begins Tracking Asteroid Steins for Flyby

Artist's impression of Rosetta doing an asteroid flyby (ESA).

[/caption]

Since waking up in early July from a brief hibernation, the Rosetta space probe has passed yet another milestone on the long journey to its rendezvous with the comet 67/P Churyumov-Gerasimenko in 2014: it has begun tracking the asteroid (2867) Steins. The spacecraft will perform a close flyby of the asteroid on September 5th, 2008, and will spend the next month taking images and science data.

Steins will remain a dot in the sky to the probe for quite a while, but these preliminary images will allow the spacecraft to get a better handle on the orbit of the asteroid, as well as its rotational period. Using the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) camera, it will image the asteroid twice a week until the 25th of August, and then will take daily images until the planned flyby on September 5th. Rosetta will pass within 800 km (500 miles) of the asteroid, imaging and taking data at the relatively slow speed of 8.6 km/second (5.3 miles/second).

The trajectory of Steins has already been established from ground-based observations, but the imaging leading up to the flyby will help to optimize the trajectory of the spacecraft. The location of the asteroid is known to within 100 km presently, but the work Rosetta will be doing will narrow that down to 2 km.

“As Rosetta’s distance from Steins decreases, the precision of the measurements for Steins’ orbit will increase even further, allowing us the best possible trajectory corrections later on before closest approach, especially in early September,” said Sylvain Lodiot, from the Rosetta Flight Control Team at the European Space Operations Centre.

During the flyby of Steins, Rosetta will study the physical and chemical properties of the asteroid. It will also provide scientists with a detailed look into the kinematic properties (how fast it is spinning), and how the asteroid interacts with the solar wind. Being so close to Stein will give Rosetta a chance to analyze any satellites of the asteroid, as well as the gas and dust in the near vicinity.

Rosetta launched in March 2004, and is taking a roundabout way to get to the final destination of comet 67/P Churyumov-Gerasimenko. It has passed by the Earth twice – once in March 2005, and once again in February 2007 – with another flyby scheduled for November 2009. While doing the most recent flyby it took this spectacular image of the Earth at night with the OSIRIS camera. The lighted regions are populated areas on continents in the Northern Hemisphere.The Earth at night as seen by Rosetta (ESA).

Earth isn’t the only celestial body that the spacecraft has visited, though. It passed within 1,000 km (620 miles) of Mars in Februrary 2007, and will perform a flyby of the asteroid 21 Lutetia in 2010. This game of planetary billiards is meant to adjust the trajectory of the spacecraft, and the imaging done on the Earth, Mars and the asteroids helps the science team work out all of the bugs in the host of science instruments on board.

Once it has arrived at 67/P Churyumov-Gerasimenko, it will deploy a lander, named Philae, which will drill into the comet to study for the first time ever the compositional nature of a comet. Rosetta will orbit the comet, following it around the Sun.

If you want to keep tabs on the progress of the Rosetta mission, the ESA has a flash animation tool that allows you to zoom in on any part of the mission.

Source: ESA Press Release

Bad Idea: Blowing Up Asteroids with Nuclear Missiles

On 4 July 2005, NASA collided a projectile with comet Tempel 1. Should a nuclear warhead be used in the future to deflect asteroids? (NASA)

[/caption]
The first thing that comes to mind when someone asks: “How do we deflect a near Earth asteroid?” is “Fire some nuclear missiles at it.” However, this might not be the best course of action. Akin to opening a walnut with a sledgehammer, there might be a better, less messy option. This is what Apollo astronaut Rusty Schweickart thinks at least. Last year, NASA issued a report suggesting they were seriously considering a nuclear option should an asteroid threaten Earth. However, the ex-lunar module pilot believes this decision was manipulated by political pressure, possibly indicating the asteroid threat was being used to speed up nuclear proliferation in space…

When ex-Apollo astronauts express an opinion, people tend to sit up and listen. After all, the astronauts throughout the space race years in the latter half of the 20th Century (from the USA and Russia) were the ultimate explorers, going above and beyond the call of duty, putting their lives on the line for their countries. Several of the retired Apollo astronauts have come forward over the years with their opinions on modern NASA, concerns for the future of the US position in space exploration and their belief in extraterrestrial cover-ups (!). And last Wednesday, during a public lecture in San Francisco, legendary astronaut Rusty Schweickart voiced his opinion about NASA’s decision to use nuclear technology when faced with an asteroid threat.

Schweickart has expressed concern with the possibility of using nuclear weapons to destroy, or deflect Earth-bound asteroids, pointing out there are many other less harmful ways of dealing with the asteroid threat. At the moment he points out that we are completely unprepared to deal with asteroids, but by 2015, we should have developed a gentler means of deflection. Simply blowing asteroids up have many knock-on implications. First and foremost, Schweickart believes that NASA may be open to manipulation to put forward the proliferation of space-based nuclear weapons under the guise of international “safety.” Another problem I can see is blowing up a large piece of rock only to create many smaller (but just as deadly) pieces of rock, doesn’t really extinguish the destructive power of an asteroid on collision course, in fact, it might increase it.

Schweickart’s organization, the B612 Foundation examines other, more subtle ways of deflecting dangerous asteroids are examined (nuclear warheads not included). Decisions such as when to take action, how to better track asteroids and how to deflect them should be an international effort and not one nation’s decision to detonate a nuclear bomb in space.

Source: Wired

Where Do Meteorites Come From?

If you’ve ever held a real meteorite in your hand, you probably wanted to know, “Where has this rock been in space and where did it come from?” Until now, no one has been able to definitively establish where the majority of meteorites found on Earth came from because of the changes that occur in meteorites after they are ejected from the asteroids they were originally part of. The most common type of meteorite found on Earth, about 75% of those identified, are chondrites, stony bits of space rocks that didn’t undergo any melting while out in space. Two astronomers say have determined that most of these meteorites come from the asteroid belt between Mars and Jupiter. Using the GEMINI telescope, they found that asteroids in that region are similar to chondrites found on Earth.

This discovery is the first observational match between the most common meteorites and asteroids in the main belt. It also confirms the role of space weathering in altering asteroid surfaces.

To find the parent asteroid of a meteorite, the astronomers compared the spectra of a meteorite specimen to those of asteroids. This is a difficult task because meteorites and their parent asteroids underwent different processes after the meteorite was ejected. In particular, surfaces of asteroids are known to be altered by a process called “space weathering”, which is probably caused by micrometeorite and solar wind action that changes the surface and spectra of asteroid surfaces.

Meteoroids are created, usually when there is a collision between asteroids. When an impact of a large asteroid occurs, the fragments broken off can follow the same orbit as the primary asteroid. These groups of fragments are called “asteroid families.” Until recently, most of the known asteroid families have been very old (they were formed 100 million to billions of years ago), and younger families are more difficult to detect because asteroid fragments are closer to each other.

In 2006, four new, extremely young asteroid families were identified, with an age ranging from 50,000 to 600,000 years. The astronomers, Thais Mothé-Diniz from Brazil and David Nesvorný from the US observed these asteroids, obtaining visible spectra. They compared the asteroids spectra to the spectra of an ordinary chondrite (the Fayetteville meteorite, shown in the top photo) and found they matched.

Identifying the parent asteroid of a meteorite is a unique tool when studying the history of our solar system because one can infer both the time of geological events (from the meteorite that can be analyzed through dating techniques) and their location in the solar system (from the location of the parent asteroid).

Meteorites are also a major tool for knowing the history of the solar system because their composition is a record of past geologic processes that occurred while they were still incorporated in the parent asteroid.

Original News Source: Astronomy and Astrophysics