Scheila (

minor planet designation A formal minor-planet designation is, in its final form, a number–name combination given to a minor planet (asteroid, centaur, trans-Neptunian object and dwarf planet but not comet). Such designation always features a leading number (catalog or ...

: 596 Scheila) is a

main-belt The asteroid belt is a torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. It contains a great many solid, irregularly shaped bodies, of many sizes, but much smaller than planets, called ...

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

and

main-belt comet Active asteroids are small Solar System bodies that have asteroid-like orbits but show comet-like visual characteristics. That is, they show comae, tails, or other visual evidence of mass-loss (like a comet), but their orbit remains within Jup ...

orbiting the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

. It was discovered on 21 February 1906 by

August Kopff August Kopff (February 5, 1882 – April 25, 1960) was a German astronomer and discoverer of several comets and asteroids. Kopff studied and worked in Heidelberg, getting his PhD there in 1906 and he then joined the Humboldt University of Berli ...

from

Heidelberg Heidelberg (; Palatine German language, Palatine German: ''Heidlberg'') is a city in the States of Germany, German state of Baden-Württemberg, situated on the river Neckar in south-west Germany. As of the 2016 census, its population was 159,914 ...

. Kopff named the asteroid after a female English student with whom he was acquainted.

Overview

On 11 December 2010, Steve Larson of the

Catalina Sky Survey Catalina Sky Survey (CSS; obs. code: 703) is an astronomical survey to discover comets and asteroids. It is conducted at the Steward Observatory's Catalina Station, located near Tucson, Arizona, in the United States. CSS focuses on the search ...

detected a comet-like appearance to asteroid Scheila: it displayed a "

coma A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. Coma patients exhi ...

" of about

magnitude Magnitude may refer to: Mathematics *Euclidean vector, a quantity defined by both its magnitude and its direction *Magnitude (mathematics), the relative size of an object *Norm (mathematics), a term for the size or length of a vector *Order of ...

13.5. Inspection of archival Catalina Sky Survey observations showed the activity was triggered between 11 November 2010 and 3 December. Imaging with the 2-meter

Faulkes Telescope North The Faulkes Telescope North is a clone of the Liverpool Telescope, and is located at Haleakala Observatory in the U.S. state of Hawaii. It is a f/10 Ritchey-Chrétien telescope. The telescope is owned and operated by LCOGT. This telescope and ...

revealed a linear tail in the anti-sunward direction and an orbital tail, indicative of larger slower particles.Richard Miles'
posting on Yahoo minor planet mailing list (MPML)
/ref> When first detected it was unknown what drove the

ejecta Ejecta (from the Latin: "things thrown out", singular ejectum) are particles ejected from an area. In volcanology, in particular, the term refers to particles including pyroclastic materials (tephra) that came out of a volcanic explosion and magma ...

plumes. Scheila's gravity is too large for

electrostatics Electrostatics is a branch of physics that studies electric charges at rest (static electricity). Since classical times, it has been known that some materials, such as amber, attract lightweight particles after rubbing. The Greek word for amber ...

to launch dust. Cometary

outgassing Outgassing (sometimes called offgassing, particularly when in reference to indoor air quality) is the release of a gas that was dissolved, trapped, frozen, or absorbed in some material. Outgassing can include sublimation and evaporation (which a ...

could not be ruled out until detailed

spectroscopic Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter wa ...

observations indicated the absence of gas in Scheila's plumes. Observations by the

Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versa ...

and the

Neil Gehrels Swift Observatory Neil Gehrels Swift Observatory, previously called the Swift Gamma-Ray Burst Explorer, is a NASA three-telescope space observatory for studying gamma-ray bursts (GRBs) and monitoring the afterglow in X-ray, and UV/Visible light at the location o ...

's ultraviolet-optical telescope make it most likely that Scheila was impacted at ~5

km/s The metre per second is the unit of both speed (a scalar quantity) and velocity (a vector quantity, which has direction and magnitude) in the International System of Units (SI), equal to the speed of a body covering a distance of one metre in a ...

by a previously unknown asteroid ~35 meters in diameter. Each asteroid the size of Scheila might be hit by an impactor 10–100 meters in diameter approximately every 1000 years, so with 200 asteroids of this size or bigger in the asteroid belt, we can observe a collision as often as every 5 years. As a consequence of the 2010 impact, the surface spectrum of Scheila changed, from a moderately red T-type spectrum to a more reddish D-type spectrum, showing how "fresh" material weathers over time in space. This is similar to laboratory experiments done on the

Tagish Lake meteorite The Tagish Lake meteorite fell at 16:43 UTC on 18 January 2000 in the Tagish Lake area in northwestern British Columbia, Canada. History Fragments of the Tagish Lake meteorite landed upon the Earth on January 18, 2000, at 16:43 UT (08:43 local t ...

. Scheila last came to

perihelion An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ellip ...

on 2012 May 19.

References

External links

Comet-like appearance of (596) Scheila
(Remanzacco Observatory)

(AARTScope Blog) * Joseph Brimacomb
animation
on flickr
(596) Scheila 2010-12-12 10:45:39UT
(cbellh47 @ flickr)
(596) Scheila by Rolando Ligustri (CAST-Italia)

Comet-like appearance of (596) ScheilaMPML
at Yahoo Groups)
Asteroid 596 Scheila "Outburst"
(Unmanned SpaceFlight)
asteroid 596 Scheila goes cometary!
(Cloudy Nights) * (University of Arizona 2010 Dec 21)

(04.28.11) * *
The cause of asteroid Scheila’s outburst
(EPSC-DPS JOINT MEETING 2011 PRESS NOTICE)
Lightcurve plot of 596 Scheila
Palmer Divide Observatory, '' B. D. Warner'' (2005) * * {{DEFAULTSORT:Scheila 000596 000596 Discoveries by August Kopff Named minor planets Small-asteroids collision 000596 000596 19060221

Overview

See also

References

External links