2008 HJ is a sub-kilometer
asteroid
An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). As ...
, classified as
near-Earth object
A near-Earth object (NEO) is any small Solar System body orbiting the Sun whose closest approach to the Sun ( perihelion) is less than 1.3 times the Earth–Sun distance (astronomical unit, AU). This definition applies to the object's orbit a ...
of the
Apollo group
Apollo Education Group, Inc. is an American corporation based in the South Phoenix area of Phoenix, Arizona, with an additional corporate office in Chicago, Illinois. It is privately-owned by a consortium of investors including The Vistria Grou ...
.
It was discovered by
Lincoln Laboratory ETS, New Mexico. Observers M. Bezpalko, D. Torres, R. Kracke, G. Spitz, J. Kistler. Richard Miles using the
Faulkes Telescope South at
Siding Spring Observatory
Siding Spring Observatory near Coonabarabran, New South Wales, Australia, part of the Research School of Astronomy & Astrophysics (RSAA) at the Australian National University (ANU), incorporates the Anglo-Australian Telescope along with a coll ...
,
Australia
Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
determined that the asteroid rotates rapidly. It measures only 12 m by 24 m and is very dense, having a mass of about 5,000
tonne
The tonne ( or ; symbol: t) is a unit of mass equal to 1,000 kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton in the United States to distinguish it from the non-metric units of the s ...
s. If the asteroid were not dense, it is probable that the rapid rotation would cause the asteroid to disrupt and fly apart.
At the time of discovery, had the smallest known
rotation period
In astronomy, the rotation period or spin period of a celestial object (e.g., star, planet, moon, asteroid) has two definitions. The first one corresponds to the '' sidereal rotation period'' (or ''sidereal day''), i.e., the time that the objec ...
in the
Solar System
The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...
, completing one revolution every 42.7 seconds.
[
It is listed on the ]Sentry Risk Table
Sentry is an automated impact prediction system started in 2002 and operated by the Center for Near Earth Object Studies (CNEOS) at NASA's Jet Propulsion Laboratory. It continually monitors the most up-to-date asteroid catalog for possibilities ...
with a 1 in 17,000 chance of impacting Earth on May 2, 2081.[ An impact from this object would be comparable to the ]Chelyabinsk meteor
The Chelyabinsk meteor () was a superbolide that entered Earth's atmosphere over the southern Ural region in Russia on 15 February 2013 at about 09:20 YEKT (03:20 UTC). It was caused by an approximately , near-Earth asteroid that entered ...
.
See also
*List of fast rotators (minor planets)
This is a list of fast rotators—"minor planets" (which includes asteroids) that have an exceptionally short rotation period, i.e. high rotation rate or spin rate. In some cases the rotation period is not constant because the object tumb ...
References
External links
MPEC 2008-H26 : 2008 HJ
(Discovery)
*
*
*
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Minor planet object articles (unnumbered)
Potential impact events caused by near-Earth objects
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20080424
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