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It’s a Bird, It’s a Plane! No, It’s an Asteroid -- Asteroid (31531) ARRL, To Be Exact!

07/31/2010

John, Paul, George and Ringo are on the list. Mozart, Bach, Beethoven and Brahms -- even Frank Zappa and Elvis (but not Madonna). Of course Asimov and Sagan made the cut, Mr Spock, too, but not Captain Kirk. And now ARRL -- more precisely, (31531) ARRL -- joins this prestigious company as one of more than 16,000 named minor planets in our solar system. A minor planet -- such as an asteroid --is an astronomical object in direct orbit around the Sun that is neither a dominant planet -- such as Mercury, Saturn and Neptune -- nor a comet. The first minor planet -- named Ceres -- was discovered in 1801. Since then, more than 200,000 minor planets have been discovered, most of them lying in the asteroid belt. But as of July 27, 2010, only 16,005 had been named.

Approximately 2.5-4 miles (3-7 km) long -- (31531) ARRL orbits the Sun at a distance of 2.7 Astronomical Units (AU) (1 AU is the distance from the Earth to the Sun, about 93 million miles, or almost 150 million km). It is currently located near the boundary of the constellations Scorpio and Libra and is about 2.1 AU distant from the Earth. It takes (31531) ARRL almost five years to orbit the Sun.

At a magnitude of brightness of 19.5, (31531) ARRL is extremely faint. This is almost 15 magnitudes fainter than the human eye can see from most cities and towns; 5 magnitudes is a factor of 100 in brightness, so this object (at its time of discovery) was about 100 × 100 × 100, or 1 million times fainter than the naked eye can see. The asteroid remains about 19th magnitude most of the time and does not brighten considerably, so (31531) ARRL will never be seen with the naked eye (unless via spacecraft). Even though it is faint, it is probably within the range of a moderate to large amateur telescope equipped with a CCD.

Joe Montani, W7DXW -- senior research specialist with the Spacewatch Near-Earth Asteroid Project Lunar and Planetary Lab at the University of Arizona -- told the ARRL that he had discovered (31531) ARRL in his work discovering and observing Near-Earth Asteroids (NEAs). He said he had received confirmation that the asteroid had been officially named as of July 27; it can take 10 years or more for the smaller objects -- such as asteroids, dwarf planets and comets -- to receive names. (31531) ARRL was discovered in 1999.

“The naming was proposed to the International Astronomical Union (IAU) Committee on Small Bodies Nomenclature (CSBN), and was accepted by the CSBN and published to the world on July 27, 2010 at about 1900 UTC,” Montani said. “The full name of the object is (31531) ARRL. The number in parenthesis is the so-called ‘permanent number’ that an asteroid receives after its orbit is sufficiently accurately determined so that it can never become ‘lost.’ ‘ARRL, is, of course, the acronym of the American Radio Relay League.”

All proposed names are judged by the CSBN, which is comprised of professional astronomers with research interests connected with minor planets and/or comets from around the world. The name must also be 16 characters or less in length, preferably one word, pronounceable in at least one language, non-offensive and not too similar to an existing name of a minor planet or natural planetary satellite. The names of individuals or events principally known for political or military activities are unsuitable until 100 years after the death of the individual or the occurrence of the event. Names of pet animals are discouraged, and names of a purely or principally commercial nature are not allowed.

In proposing to name an object, the proposer must supply the IAU committee a brief written citation, no more than four lines of ASCII text of 78 characters per line, formatted in a special way. “The full text of the citation I wrote for (31531) ARRL contains information about the ARRL that I gleaned from the ARRL Web site,” Montani explained. “With the announcement of the naming, the citation is published and recorded for all time. The citation serves as an explanation of the naming and gives a sense of the motivation for it.”

The citation for (31531) ARRL reads: “Since 1914, the American Radio Relay League has been the largest membership organization of radio amateurs in the US. ARRL promotes interest in ‘ham’ radio and experimentation, maintains high standards of conduct and fraternalism among hams and represents their interests in matters legislative.”

Prior to the object receiving its permanent number, Montani said that (31531) ARRL was known by its permanent designation of 1999 CQ137. “I selected this object for naming from among the many thousands discovered by Spacewatch,” he told the ARRL. “It seemed fitting to me that ‘CQ’ should be in the designation. In addition, the number 137 is also significant to physicists and engineers and perhaps to radio amateurs: It is the reciprocal of the ‘fine-structure constant’ that depends on the square of the charge on the electron, the speed of light, Planck’s constant and the permittivity of free space. This object seemed to have it all for us!”

Montani discovered (31531) ARRL using the .9 meter (36 inch) Steward Observatory Spacewatch telescope, located on Kitt Peak outside of Tucson, Arizona. The telescope, which saw first light in 1921, was also the telescope that was used to discover the 30 Hz pulsar located in the center of the Crab Nebula. In 1980, Tom Gehrels and Bob McMillan founded the Spacewatch program. The primary goal of Spacewatch is to explore the various populations of small objects in the solar system and study the statistics of asteroids and comets in order to investigate the dynamical evolution of the solar system. CCD scanning studies the Centaur, Trojan, Main-Belt, Trans-Neptunian and Earth-approaching asteroid populations. Spacewatch also finds potential targets for interplanetary spacecraft missions, provides follow-up astrometry of such targets and finds objects that might present a hazard to the Earth.



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