Marshall Space Flight Center – Page 12

Bright Fireball Flames in Southern Skies

Editor’s Note: A rare snowstorm isn’t the only interesting thing that happened across the South this past week. On the night of Tuesday, Jan. 11, an extremely bright fireball meteor streaked over Jackson, Miss., and was visible across several southern states. NASA astronomer Bill Cooke of the Meteoroid Environment Office at Marshall Space Flight Center confirms the meteor below.

Okay folks, can confirm that this was indeed a fireball or bolide. Unfortunately no video of the actual meteor has surfaced, so I requested an analysis of signals from North American infrasound stations. We had one very clear detection, from the ELFO station in Canada, and a marginal signal at another station east of the visual sightings. Unfortunately the marginal signal is too weak to permit extraction of much information or to triangulate.

The ELFO signal arrived at 10:05:50 PM Central time, some 1 hour and 20 minutes after the event, and came in at an azimuth of 210 degrees. If you look at the attached plot, the black curved line shows the path of the ELFO signal, which intersects nicely with the bulk of the visual observations — indicated by the red dot — around Jackson, Mississippi (ELFO az gives 32 deg N, 89 deg W — Jackson is at 32 deg N, 90 deg W).

The infrasound signal at ELFO lasted some 2.5 minutes, and the amplitude permits an estimate of the meteor’s energy at 40-80 tons of TNT. If we assume a speed of 15 kilometers per second, we can derive a mass of 171 kg or 376 pounds. Making a further assumption that the meteor was porous rock gives a size, or diameter, of 0.54 meters or 21 inches.

That’s the best estimate at this time — if video data of the meteor itself shows up, please let me know. Don’t hesitate to ask questions if you need clarification or more information.

Lunar Eclipse, Sprinkled With Fireballs

The 2010 solstice lunar eclipse is one for the books, but check out these images from two cameras in the Canadian all-sky meteor camera network.These cameras are similar to the ones used for observation at NASA’s Marshall Space Flight Center: all-sky, black-and-white, and detecting bright meteors, or fireballs. Below are two stacked images of the eclipse:

Stacked image of the eclipse using images taken every five minutes from McMaster University
between 6:32 and 9:32 UT.

A similarly stacked image, combining pictures every five minutes between 5:27-9:37;
it was taken from Orangeville, ON, Canada.

Just as a reminder, the eclipse event timings in UT were:

Partial begins: 6:33
Total begins: 7:41
Mid eclipse: 8:17
Total ends: 8:53
Partial ends: 10:01

So both cameras captured the full moon as it normally appears, then imaged it as it was eclipsed through the partial and total phases. Unfortunately, bad weather rolled in before the eclipse ended!

The Canadian cameras also detected meteors during the eclipse. Here are a few good ones:

The following two images were also taken from McMaster and Orangeville at about 7:38 UT, just before the total eclipse began, but after the partial eclipse had started. These pictures show an image of a meteor fairly close to the moon in the field of view.

The following three images were recorded from Elginfield, ON, Canada, McMaster, and Orangeville, respectively, at about 9:00 UT, just after the total eclipse phase ended, but before the partial eclipse ended. This meteor ablated by a height of 83 kilometers, or 52 miles.

Images courtesy of the Meteor Physics Group at the University of Western Ontario in London, ON, Canada
Text courtesy of Danielle Moser, NASA’s Marshall Space Flight Center, Meteoroid Environment Office

596 Scheila: An Identity Crisis?

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.

Live Web Chats Today: Geminid Meteor Shower

Baby, it’s cold outside — but you can still enjoy the best meteor shower of the year. The 2010 Geminid meteor shower promises to be lively, with realistic viewing rates of 50-80 meteors per hour and potential peaks reaching 120 meteors per hour. Anytime between Dec. 12-16 is a valid window for Geminid-watching, but the night of Dec. 13-14 is the anticipated peak.

You have two opportunities to learn more about the Geminids from meteor experts based at NASA’s Marshall Space Flight Center. On Monday, Dec. 13 from 3:00 to 4:00 p.m. EST, meteor experts Danielle Moser and Rhiannon Blaauw will answer your questions, then you can stay “up all night” to observe the Geminids with NASA astronomer Bill Cooke. Have the coffee ready, then join them online from 11:00 p.m. to 5:00 a.m. EST as the Geminids peak in the skies over Earth.

Joining the chats is easy. Simply go to https://www.nasa.gov/connect/chat/geminids2010.html a few minutes before each of the chat start times list above. The chat module will appear at the bottom of this page. After you log in, wait for the chat module to be activated, then ask your questions. Here’s to a spectacular viewing!

False-color composite view of 2008 Geminid meteor shower is courtesy of Bill Cooke, NASA’s Meteoroid Environment Office at the Marshall Space Flight Center.

Here Come the Geminids!

Last night the NASA All-sky Meteor cameras detected their first Geminid fireball of 2010! The fireball, detected from cameras positioned in both Huntsville, Ala., and Chickamauga, Ga., was first spotted over southern Tennessee at a height of 58.7 miles above the ground. It streaked across the sky over northern Alabama at a speed of 76,300 mph and completely burned up by a height of 53.4 miles. If the weather remains clear, we should be in for a good Geminid show this year!

Geminid fireball meteor seen from Huntsville (left) and Chickamauga (right) on December 6, 2010.

Meteor rates should peak early next week, so stay tuned for more news about the Geminid meteor shower!

Image courtesy of Danielle Moser, NASA’s Meteoroid Environment Office, Marshall Space Flight Center, Huntsville, Ala.

Ikeya-Murakami: The New Comet on the Cosmic Block

The animation below shows the motion of Comet Ikeya-Murakami on Nov. 13, 2010, captured with a New Mexico-based telescope operated remotely by NASA’s Marshall Space Flight Center. The images were taken near dawn and show the comet’s movement over a period of 45 minutes. Each exposure was three minutes in length, and the faint angled streak around 0:10 in the animation is a satellite trail. At the time of these images, the comet was some 229 million miles away from Earth.

Comet Ikeya-Murakami was discovered very recently on Nov. 3, 2010, by Japanese amateur astronomers Kaoru Ikeya and Shigeki Murakami. Their discovery is unusual because they both used manual observations through optical telescopes to identify the comet. Such observations are rare in recent times when astronomers use cutting-edge digital imaging to study the skies.

Ikeya-Murakami is classified as a long-period comet, or those comets having eccentric orbits ranging from 200 years millions of years to make one circuit around the sun.

Courtesy of Rob Suggs, NASA’s Meteoroid Environment Office, Marshall Space Flight Center, Huntsville, Ala.

Full Moon Doesn't Phase Orionids Viewing

Despite the fullness of the moon, the all-sky meteor camera at NASA’s Marshall Space Flight Center in Huntsville, Ala., managed to detect a decent number of Orionid meteors this October — 41 in total! Thesemeteors, produced by debris from Halley’s Comet, travel at 146,000miles per hour and burn up high in the atmosphere. Most Orionids werefirst detected around an altitude of 68 miles, and completely burned upby a height between 58 and 60 miles above the ground.

Shown below are two Orionid meteors observed on Oct. 21, 2010. The shower radiant, located near the constellation Orion, is easily visible.

The Orionids peaked on October 21 when the all-sky camera detected 13 double station Orionid meteors.

Images courtesy of Danielle Moser, NASA’s Meteoroid Environment Office, Marshall Space Flight Center, Huntsville, Ala.

Tiny Asteroid 2010 TG19 Approaches Earth

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.

Only 11.5 Million Miles Away Now!

MSFC astronomer Bill Cooke took this five-minute exposure of Comet Hartley 2 late on the night of Saturday, Oct. 16, 2010, using a 10″ telescope in New Mexico.

The comet, which has now reached naked eye visibility, was just under 11.5 million miles from Earth and sporting a coma over a degree across — twice the size of the full moon. You can read more about the “coma” and other parts of a comet at the NASA Worldbook: Comets page.

This very active visitor to our neighborhood makes its closest approach around 8 a.m. EDT on Oct. 20, at a distance of 11.2 million miles. Unfortunately, the light from the nearly full moon will tend to wash out the comet’s pale green glow, so comet watchers are advised to make use of a pair of binoculars for the best view.

Image courtesy of Bill Cooke, NASA’s Meteoroid Environment Office, Marshall Space Flight Center, Huntsville, Ala.

Camel Leopards and Comets

Camelopardalis.

It’s a strange-sounding name for a constellation, coming from the Greco-Roman word for giraffe, or “camel leopard”. The October Camelopardalids are a collection of faint stars that have no mythology associated with them — in fact, they didn’t begin to appear on star charts until the 17th century.

Even experienced amateur astronomers are hard-pressed to find the constellation in the night sky. But in early October, it comes to prominence in the minds of meteor scientists as they wrestle with the mystery of this shower of meteors, which appears to radiate from the giraffe’s innards.

The October Camelopardalids are not terribly spectacular, with only a handful of bright meteors seen on the night of Oct. 5. It may have been first noticed back in 1902, but definite confirmation had to wait until Oct. 2005, when meteor cameras videotaped 12 meteors belonging to the shower. Moving at a speed of 105,000 miles per hour, Camelopardalids ablate, or burn up, somewhere around 61 miles altitude, according to observations from the NASA allsky meteor cameras on the night of Oct. 5, 2010.

So they aren’t spectacular. Their speed is calculated. Their “burn up” altitudes and orbits are known. So what’s the mystery?

Camelopardalids have orbits, which indicates that they come from a long period comet, like Halley’s Comet. But the Camelopardalids don’t come from Halley, nor from any of the other comets that have been discovered. Hence the mystery: somewhere out there is — or was — a comet that passes close to Earth which has eluded detection. These tiny, millimeter size bits of ice leaving pale streaks of light in the heavens are our only clues about a comet of a mile, maybe more, in diameter.

This is why astronomers keep looking at the Camelopardalids meteors. They hope that measuring more orbits may eventually help determine the orbit of the comet, enabling us to finally locate and track this shadowy visitor to Earth’s neighborhood.