Subscribe free to our newsletters via your
. 24/7 Space News .




IRON AND ICE
Formation of Scheila's Triple Dust Tails Explained
by Staff Writers
Seoul, Korea (SPX) Oct 20, 2011


Optical images of Scheila at three different epochs with different telescopes. Images of the triple dust tails were taken on the 12th and 19th of December 2010 using the Murikabushi Telescope. Bottom: Suprime-Cam on the Subaru Telescope captured this image of the linear structure on the 2nd of March 2011. For a larger version of this image please go here.

A research team of planetary scientists and astronomers, mainly from Seoul National University, the National Astronomical Observatory of Japan (NAOJ), the Institute of Space and Astronautical Science (ISAS), and Kobe University, has explained the formation of peculiar triple dust tails from the asteroid Scheila (asteroid #596).

The researchers concluded that another asteroid about 20-50 meters in size impacted Scheila from behind on December 3, 2010, and accounted for its unusual brightness and form.

On December 11.4, 2010, Steve Larson of the Catalina Sky Survey noticed an odd brightness from Scheila, an asteroid on the outer region of the main belt of asteroids that orbit in an area between Mars and Jupiter.

Three streams of dust appeared to trail from the asteroid. Data from NASA's Swift Satellite and the Hubble Space Telescope suggested that a smaller asteroid's impact was the likely trigger for the appearance of comet-like tails from Scheila.

However, questions remained about the date when the dust emission occurred and how the triple dust tails formed. The current research team sought answers to these queries.

Soon after reports of Scheila's unusual brightness, the current research team used the Subaru Prime Focus Camera (Suprime-Cam) on the Subaru Telescope (8.2 m), the Ishigakijima Astronomical Observatory Murikabushi Telescope (1.05 m), and the University of Hawaii 2.2 m Telescope to make optical observations of these mysterious dust tails over a three-month period.

The top of Figure 1 shows images of the development of the dust tails taken by the Murikabushi Telescope on the 12th and 19th of December 2010. Although asteroids generally look like points when observed from Earth, Scheila looked like a comet.

As the three streaks of dust streamed from the asteroid, their surface brightness decreased. Eventually the dust clouds became undetectable, and then a faint linear structure appeared.

The bottom of Figure 1 shows the image obtained by Subaru Telescope on March 2, 2011. Based on these images of the linear structure, the scientists determined a dust emission date of December 3.5+/-1, 2010. Steve Larson of the Catalina Sky Survey noticed that Scheila had a slightly diffuse appearance on December 3.4, 2010.

Therefore, it is likely that the collision of the asteroids occurred within the short time between December 2 12:00 UT and December 3 10:00 UT.

To explain the formation of Scheila's triple dust tails, the research team conducted a computer simulation of Scheila's dust emission on December 3th.

Their simulation was based on information gained through impact experiments in a laboratory at ISAS, a hypervelocity impact facility and division of the Japan Aerospace Exploration Agency (JAXA). Figure 2 shows the ejecta produced by an oblique impact, which was not a head-on collision.

Two prominent features characterize oblique impacts and the shock waves generated by them. One feature, a downrange plume, occurs in a direction downrange from the impact site and results from the fragmentation or sometimes evaporation of the object that impacted another.

A second feature occurs during the physical destruction of the impacted object; a shock wave spreads from the impact site, scoops out materials (conical impact ejecta), and forms an impact crater. The axis of the cone of ejecta is roughly perpendicular to the surface at the impact site.

The team reasoned that these two processes caused the ejection of Scheila's dust particles and that sunlight pushed them away from the asteroid. After performing a tremendous number of computer simulations under different conditions, they could only duplicate their observed images when an object struck Scheila's surface from behind (Figures 3 and 4).

Taking all of the evidence into account-their observations and simulations--the research team concluded that there is only one way to explain the mysterious brightness and triple tails of dust from Scheila. A smaller asteroid obliquely impacted Scheila from behind.

References: Ishiguro et al. 2011, Astrophysical Journal Letters 740, L11, "Observational Evidences for Impact on the Main-Belt Asteroid (596) Scheila"; Ishiguro et al. 2011, Astrophysical Journal Letters, 741, L24, "Interpretation of (596) Scheila's Triple Dust Tails"

.


Related Links
National Astronomical Observatory of Japan (NAOJ)
Asteroid and Comet Mission News, Science and Technology






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





IRON AND ICE
Hyperactive Hartley 2 has a split history
Nantes, France (SPX) Oct 10, 2011
The latest analysis of data from NASA's Deep Impact spacecraft shows that comet 103P/Hartley 2 is hyperactive in terms of the material it spews out, compared to the other comets observed up close to date. The comet also shows surprising diversity - ice on the comet's sunlit surface is found in patches that are isolated from areas of dust. In addition, one lobe of the dog-bone shaped comet ... read more


IRON AND ICE
Lunar Probe to search for water on Moon

Subtly Shaded Map of Moon Reveals Titanium Treasure Troves

NASA's Moon Twins Going Their Own Way

Titanium treasure found on Moon

IRON AND ICE
Mars Landing-Site Specialist

New Mystery on Mars's Forgotten Plains

Russian scientists want to join Europe's ExoMars mission

UK Space Agency announces seed funding for Mars exploration

IRON AND ICE
Space tourism gaining momentum

NASA Veteran Alan Stern to Lead Florida Space Institute

Astrotech Subsidiary Awarded Task Order for NASA Mission

ASU in space: 7 current missions, more in the wings

IRON AND ICE
China's first space lab module in good condition

Takeoff For Tiangong

Snafu as China space launch set to US patriotic song

Civilians given chance to reach for the stars

IRON AND ICE
Expedition 30 to ISS could be launched on Dec 21

ISS could be used for satellite assembly until 2028

Ultrasound 2: Taking Space Imaging to the Next Level

CU-Boulder to play key role in global student space experiment competition

IRON AND ICE
ILS Proton Launches ViaSat-1 for ViaSat

Final checks for first Soyuz launch from Kourou

Soyuz is put through its paces for Thursday's launch

Russia blames scientists for rocket crashes

IRON AND ICE
NASA's Spitzer Detects Comet Storm In Nearby Solar System

Photo Reveals Planet-Size Object as Cool as Earth

Spiral Arms Point to Possible Planets in a Star's Dusty Disk

UChicago launches search for distant worlds

IRON AND ICE
Greenpeace criticises Japan radiation screening

Apple profit soars but misses high expectations

China rare earths giant halts output as prices fall

Camera lets people shoot first, focus later




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement