On November 11 at 5:41:17 PM CST there was a fireball detected on two NASA cameras; one located at Marshall Space Flight Center in Huntsville, Alabama and the other in Tullahoma, TN.
Last evening’s fireball was just across the Tennessee/Arkansas border over the town of Jonesboro, Arkansas (NW of Memphis – see ground track image below). Speed was about 43,000 mph, and the object weighed around 10 pounds (6 inches in diameter).
The orbit, which extends well beyond Mars, indicates that the meteoroid is a piece of an asteroid.
So how can we tell that the Russian meteor isn’t related to asteroid 2012 DA14?
One way is to look at meteor showers — the Orionids all have similar orbits to their parent comet, Halley. Similarly, the Geminids all move in orbits that closely resemble the asteroid 3200 Phaethon, which produced them. So if the Russian meteor was a fragment of 2012 DA14, it would have an orbit very similar to that of the asteroid.
It does not…
If you look at the image, the orbit of the Earth is the green circle. That of 2012 DA14 is the blue ellipse that is almost entirely within the orbit of the Earth; notice that it is close to circular. The other blue ellipse, stretching way beyond the orbit of Mars, is the first determination of the orbit of the Russian meteor. Notice that the two are nothing alike; in fact, they aren’t even close.
This is one reason — a big one — why NASA says the asteroid 2012 DA14 are not connected.
According to NASA scientists, the trajectory of the Russian meteor was significantly different than the trajectory of the asteroid 2012 DA14, making it a completely unrelated object. Information is still being collected about the Russian meteor and analysis is preliminary at this point. In videos of the meteor, it is seen to pass from left to right in front of the rising sun, which means it was traveling from north to south. Asteroid DA14’s trajectory is in the opposite direction, from south to north.
This is the most common question we are asked, and the answer is “maybe.” It all depends on where you are located and what sort of equipment you have.
Closest approach will be around 19:25 UTC on February 15; this will be when the asteroid will be at its brightest. Even at this time, when 2012 DA14 is only about 17,000 miles above Earth’s surface, it will not be visible to the unaided eye due to its small size. Observers in Indonesia (which is favored to see close approach) will need binoculars to catch a glimpse of the asteroid as it moves rapidly through the sky.
The rest of us will need to use a telescope. In North America, 2012 DA14 will be no brighter than magnitude 11 when the Sun sets on the 15th. This is over 60 times fainter than the faintest star you can see with your eyes under perfect sky conditions. Also, it will still be moving quickly through the constellations — over 3 degrees (6 Moon diameters) per hour — and this speed, combined with its fading, will make it a challenging target, even for experienced amateurs. Algorithms in many of the software programs used to drive telescopes are not suited for fast movers like this one, and may point the telescope in the wrong locations (A test we conducted using a popular software package showed that it would point the telescope over a degree away from the actual position of DA14, well outside the one half degree field of view of most instruments). So seeing 2012 DA14 before it fades beyond the limit of most amateur telescopes will not be a simple task; it will require some thought and advanced planning. An invaluable tool in planning your observations is the JPL Horizons website (http://ssd.jpl.nasa.gov), which can calculate the precise positions of 2012 DA14 for your location.
So can I see 2012 DA 14? The answer is yes — if you have access to a decent telescope, if you take the time to figure out where you need to look in advance, and if your sky is clear. A lot of work, but the reward is a glimpse of a house-size visitor from another part of the Solar System as it whizzes by our planet at a distance closer than many of the communications satellites we depend upon in our daily lives. A rare event, to be sure.
Those without telescope access may also get a glimpse. NASA will be streaming the latter part of the asteroid flyby on Ustream at http://www.ustream.tv/channel/nasa-msfc – if the skies are clear in Alabama and the MSFC-based telescope can view DA14, you can use the Internet to get a peek at 2012 DA14 (which will look like a fast moving star) from the comfort of your home.
Things are getting a little stranger in the asteroid belt these days! Objects in this zone of the solar system are known to be rocky bodies, though in the past few years several of these bodies have had cometary features detected. One such body is 596 Scheila, which has always been confidently called a main-belt asteroid, meaning it is a rocky body orbiting nicely between Mars and Jupiter causing no trouble to Earth.
Scheila is 113 km in diameter and was discovered in 1906 by August Kopff in Heidelberg and named after an acquaintance of the discoverer. For the past 104 years Scheila has been pleasantly orbiting without much fuss until last week the Catelina Sky Survey found a coma around the object with a 0.68 meter Schmidt telescope; quickly confirmed by many other observers.Scheila, along with several other bodies in the past few years, have created a new class of solar system objects: main-belt comets. Main-belt comets have the orbital characteristics of main-belt asteroids, but exhibit an outgassing, comae, or a dust-tail that is normally seen on icy comets that came from the outer-reaches of our solar system. These bodies are an anomaly and a mystery since an object this close to the sun should have had its ices vaporized away. This has caused another theory to arise that perhaps they are not icy bodies, but perhaps the trail of debris was caused by an asteroid-asteroid collision.
3200 Phaethon, the parent body of the famous Geminid meteor shower, is another example of this. Phaethon was always thought to be an asteroid, a purely rocky body, and even its meteoroids agreed with this, being denser than an average icy-meteoroid. But in recent times Phaethon has exhibited dust-outgassing, causing observers to wonder whether it once was a comet, or if it has had a recently collision to cause the particles.
Unlike Phaethon, Scheila will not intersect Earth’s orbit and thus we will not have a Scheilid meteor shower. Whether this outgassing and dust production from asteroids is due to vaporization of earth or asteroid collisions, only time will tell. Oh, the mysteries of our solar system!
Orbit of 596 Scheila, as computed by the JPL small-body database browser.
Image of 596 Scheila using a V Filter and 10 stacked images of three-minute exposures each.
Image of 596 Scheila using an R Filter and 10 stacked images of three- minute exposures each.
Images were taken via a remote-operated camera located in New Mexico. Stars are trailed because the asteroid was being tracked. You can clearly see the fuzzy “cloud” or coma about the asteroid in the center.
Images courtesy of Bill Cooke and Rhiannon Blaauw, NASA’s Meteoroid Environment Office, Marshall Space Flight Center, Huntsville, Ala.
Using the Marshall Space Flight Center 0.5 meter telescope in New Mexico, NASA astronomer Rob Suggs captured this view of the tiny asteroid 2010 TG19 as it made its way among the stars of the constellation Pegasus.
Taken before sunup on Oct. 15, the animated sequence shows the movement of the asteroid, then 4.25 million miles away from Earth, over 45 minutes. Only 75 yards across, 2010 TG19 is very faint at magnitude +18 , which is near the limit of the telescope. It will continue to approach during the next few days, finally coming within 268,500 miles of our planet, or almost as close as the moon, at noon EDT on Friday, Oct. 22.
Courtesy of Rob Suggs, Marshall Space Flight Center, Huntsville, Ala.