2014 AA was a small

Apollo Apollo, grc, Ἀπόλλωνος, Apóllōnos, label=genitive , ; , grc-dor, Ἀπέλλων, Apéllōn, ; grc, Ἀπείλων, Apeílōn, label=Arcadocypriot Greek, ; grc-aeo, Ἄπλουν, Áploun, la, Apollō, la, Apollinis, label= ...

near-Earth asteroid A near-Earth object (NEO) is any small Solar System body whose orbit brings it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun ( perihelion) is less than 1.3 astronomical units (AU) ...

roughly 2–4 meters in diameter that

struck Struck is a surname. Notable people with the surname include: * Adolf Struck (1877–1911), German author *Hermann Struck (1876–1944), German artist *Karin Struck (1947–2006), German author *Paul Struck (1776-1820), German composer *Peter Stru ...

Earth on 2 January 2014. It was discovered on 1 January 2014 by

Richard Kowalski Richard A. Kowalski (born 1963) is an American astronomer who has discovered numerous asteroids and comets, among them, many near-Earth objects. Kowalski has had a lifelong interest in astronomy with an emphasis on planetary science. As an ama ...

at the

Mount Lemmon Survey Mount Lemmon Survey (MLS) is a part of the Catalina Sky Survey with observatory code G96. MLS uses a cassegrain reflector telescope (with 10560x10560-pixel camera at the f/1.6 prime focus, for a five square degree field of view) operated by ...

at an

apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's ...

of 19 using a

reflecting telescope A reflecting telescope (also called a reflector) is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century by Isaac Newton as an alternati ...

Mount Lemmon Observatory Mount Lemmon Observatory (MLO), also known as the Mount Lemmon Infrared Observatory, is an astronomical observatory located on Mount Lemmon in the Santa Catalina Mountains approximately northeast of Tucson, Arizona (US). The site in the Corona ...

. 2014 AA was only observed over a short observation arc of about 70 minutes, and entered Earth's atmosphere about 21 hours after discovery. Nonetheless it remains one of only a few asteroids observed before impact (see

Asteroid impact prediction Asteroid impact prediction is the prediction of the dates and times of asteroids impacting Earth, along with the locations and severities of the impacts. The process of impact prediction follows three major steps: # Discovery of an asteroid and ...

Entry

Using a poorly determined orbit, the

JPL Small-Body Database The JPL Small-Body Database (SBDB) is an astronomy database about small Solar System bodies. It is maintained by Jet Propulsion Laboratory (JPL) and NASA and provides data for all known asteroids and several comets, including orbital parameters an ...

listed a 3-sigma solution with impact occurring around 2 January 2014 02:33 UT ± 1 hour and 5 minutes. The

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function T ...

listed impact as occurring around 2 January 2014 05:00 UT ± 10 hours. Independent calculations by Bill Gray, the Minor Planet Center and Steve Chesley at the

Jet Propulsion Laboratory The Jet Propulsion Laboratory (JPL) is a Federally funded research and development centers, federally funded research and development center and NASA field center in the City of La Cañada Flintridge, California, La Cañada Flintridge, California ...

verified that impact was virtually certain. It entered the atmosphere going about 11.7 km/s with respect to Earth. The impactor would have been roughly the size of , which exploded above the

Nubian Desert The Nubian Desert ( ar, صحراء النوبة, ''Şaḩrā’ an Nūbyah'') is in the eastern region of the Sahara Desert, spanning approximately 400,000 km2 of northeastern Sudan and northern Eritrea, between the Nile and the Red Sea ...

in Sudan on 7 October 2008. Calculations by Chesley suggest the impactor fell somewhere on an arc extending from Central America to East Africa, with a best-fit location just off the coast of West Africa. Calculations by Pasquale Tricarico using the nominal orbit show that 2014 AA entered Earth's shadow cone approximately 40 minutes before entering the atmosphere.

Infrasound Infrasound, sometimes referred to as low status sound, describes sound waves with a frequency below the lower limit of human audibility (generally 20 Hz). Hearing becomes gradually less sensitive as frequency decreases, so for humans to perce ...

was detected by three stations of the Comprehensive Nuclear-Test-Ban Treaty Organization. Peter Brown and Petrus Jenniskens located weak signals from infrasound stations in Bolivia, Brazil and Bermuda. 2014 AA entered Earth's atmosphere around 03:06 ± 5 min UT, 3,000 km from

Caracas Caracas (, ), officially Santiago de León de Caracas, abbreviated as CCS, is the capital and largest city of Venezuela, and the center of the Metropolitan Region of Caracas (or Greater Caracas). Caracas is located along the Guaire River in th ...

, Venezuela, far from any landmass. No ships or planes reported witnessing the event. A recalculation of the impact parameters of this meteor based on infrasound recordings puts it in the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

about 1900 km (1030 nautical miles) east of

Port of Spain Port of Spain ( Spanish: ''Puerto España''), officially the City of Port of Spain (also stylized Port-of-Spain), is the capital of Trinidad and Tobago and the third largest municipality, after Chaguanas and San Fernando. The city has a muni ...

Trinidad Trinidad is the larger and more populous of the two major islands of Trinidad and Tobago. The island lies off the northeastern coast of Venezuela and sits on the continental shelf of South America. It is often referred to as the southernmos ...

, at a longitude of impact of nearly 44º west and a latitude of 11º north, the impact time being 2456659.618 JD UTC. Extensive numerical simulations indicate that, prior to impact, 2014 AA was subjected to a number of secular resonances and it may have followed a path similar to those of the NEOs , , , and ; NEOs in this transient group experience close encounters with the Earth-Moon system at perihelion and Mars at aphelion and could be a dynamical family.

Other discoveries

Kowalski previously discovered , the first asteroid discovered before Earth impact, using the same telescope in October 2008. There are about a

billion Billion is a word for a large number, and it has two distinct definitions: *1,000,000,000, i.e. one thousand million, or (ten to the ninth power), as defined on the short scale. This is its only current meaning in English. * 1,000,000,000,000, i. ...

near-Earth objects in the size range of 2014 AA, and impacts of comparably-sized objects occur several times each year. Several years later, 2018 LA was also discovered by the Mount Lemmon Survey, and ended up impacting Earth in southern

Botswana Botswana (, ), officially the Republic of Botswana ( tn, Lefatshe la Botswana, label= Setswana, ), is a landlocked country in Southern Africa. Botswana is topographically flat, with approximately 70 percent of its territory being the Kal ...

in June 2018.

References

External links

The atmospheric impact trajectory of asteroid 2014 AA

arXiv arXiv (pronounced "archive"—the X represents the Greek letter chi ⟨χ⟩) is an open-access repository of electronic preprints and postprints (known as e-prints) approved for posting after moderation, but not peer review. It consists of ...

13 January 2016
Two maps of the possible impact region
(Yahoo groups / Project Pluto)
2014 AA – New Year’s Earth impactor
(

Carl W. Hergenrother Carl William Hergenrother (born 1973) is an American astronomer and discoverer of minor planets and comets. As credited by the Minor Planet Center, he has discovered and co-discovered 32 numbered asteroids at the Bigelow Sky Survey during 1993� ...

) * * {{DEFAULTSORT:2014 AA # Minor planet object articles (unnumbered) Discoveries by Richard Kowalski January 2014 events Predicted impact events 20140102 20140101 2014 in space

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Other discoveries

See also

References

External links