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Aries is one of the constellations of the zodiac. It is located in the Northern celestial hemisphere between Pisces to the west and Taurus to the east. The name Aries is Latin for ram. Its old astronomical symbol is (♈︎). It is one of the 48 constellations described by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations. It is a mid-sized constellation, ranking 39th overall size, with an area of 441 square degrees.
Boötes is a constellation in the northern sky, located between 0° and +60° declination, and 13 and 16 hours of right ascension on the celestial sphere. The name comes from Latin Boōtēs, which comes from Greek Βοώτης Boṓtēs 'herdsman' or 'plowman'.
Corona Australis is a constellation in the Southern Celestial Hemisphere. Its Latin name means "southern crown", and it is the southern counterpart of Corona Borealis, the northern crown. It is one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations. The Ancient Greeks saw Corona Australis as a wreath rather than a crown and associated it with Sagittarius or Centaurus. Other cultures have likened the pattern to a turtle, ostrich nest, a tent, or even a hut belonging to a rock hyrax.
The Leonids are a prolific meteor shower associated with the comet Tempel–Tuttle, which are also known for their spectacular meteor storms that occur about every 33 years. The Leonids get their name from the location of their radiant in the constellation Leo: the meteors appear to radiate from that point in the sky. Their proper Greek name should be Leontids, but the word was initially constructed as a Greek/Latin hybrid and it has been used since. They peak in the month of November.
A meteoroid is a small rocky or metallic body in outer space.
The Geminids are a prolific meteor shower caused by the object 3200 Phaethon, which is thought to be a Palladian asteroid with a "rock comet" orbit. This would make the Geminids, together with the Quadrantids, the only major meteor showers not originating from a comet. The meteors from this shower are slow moving, can be seen in December and usually peak around December 4–16, with the date of highest intensity being the morning of December 14. The shower is thought to be intensifying every year and recent showers have seen 120–160 meteors per hour under optimal conditions, generally around 02:00 to 03:00 local time. Geminids were first observed in 1862, much more recently than other showers such as the Perseids and Leonids.
A meteor shower is a celestial event in which a number of meteors are observed to radiate, or originate, from one point in the night sky. These meteors are caused by streams of cosmic debris called meteoroids entering Earth's atmosphere at extremely high speeds on parallel trajectories. Most meteors are smaller than a grain of sand, so almost all of them disintegrate and never hit the Earth's surface. Very intense or unusual meteor showers are known as meteor outbursts and meteor storms, which produce at least 1,000 meteors an hour, most notably from the Leonids. The Meteor Data Centre lists over 900 suspected meteor showers of which about 100 are well established. Several organizations point to viewing opportunities on the Internet. NASA maintains a daily map of active meteor showers.
Jodrell Bank Observatory in Cheshire, England, hosts a number of radio telescopes as part of the Jodrell Bank Centre for Astrophysics at the University of Manchester. The observatory was established in 1945 by Bernard Lovell, a radio astronomer at the university, to investigate cosmic rays after his work on radar in the Second World War. It has since played an important role in the research of meteoroids, quasars, pulsars, masers and gravitational lenses, and was heavily involved with the tracking of space probes at the start of the Space Age.
In astronomy, the zenithal hourly rate (ZHR) of a meteor shower is the number of meteors a single observer would see in an hour of peak activity if it was at the zenith, assumed the conditions are excellent. The rate that can effectively be seen is nearly always lower and decreases the closer the radiant is to the horizon.
The Quadrantids (QUA) are a meteor shower that peaks in early January and whose radiant lies in the constellation Boötes. The zenithal hourly rate (ZHR) of this shower can be as high as that of two other reliably rich meteor showers, the Perseids in August and the Geminids in December, yet Quadrantid meteors are not seen as often as those of the two other showers because the time frame of the peak is exceedingly narrow, sometimes lasting only hours. Moreover, the meteors are quite faint, with mean apparent magnitudes between 3.0 and 6.0).
Comet Encke, or Encke's Comet, is a periodic comet that completes an orbit of the Sun once every 3.3 years. Encke was first recorded by Pierre Méchain on 17 January 1786, but it was not recognized as a periodic comet until 1819 when its orbit was computed by Johann Franz Encke. Like Halley's Comet, it is unusual in its being named after the calculator of its orbit rather than its discoverer. Like most comets, it has a very low albedo, reflecting only 4.6% of the light its nucleus receives, although comets generate a large coma and tail that can make them much more visible during their perihelion. The diameter of the nucleus of Encke's Comet is 4.8 km.
3200 Phaethon, provisional designation 1983 TB, is an active Apollo asteroid with an orbit that brings it closer to the Sun than any other named asteroid. For this reason, it was named after the Greek myth of Phaëthon, son of the sun god Helios. It is 5.8 km (3.6 mi) in diameter and is the parent body of the Geminids meteor shower of mid-December. With an observation arc of 35+ years, it has a very well determined orbit. The 2017 Earth approach distance of about 10 million km was known with an accuracy of ±700 m.
The Beta Taurids (β–Taurids) are an annual meteor shower belonging to a class of "daytime showers" that peak after sunrise. The Beta Taurids are best observed by radar and radio-echo techniques.
The Southern Delta Aquariids are a meteor shower visible from mid July to mid August each year with peak activity on 28 or 29 July. The Comet of origin is not known with certainty. Suspected candidate is Comet 96P Machholz. Earlier, it was thought to have originated from the Marsden and Kracht Sungrazing comets.
The Taurids are an annual meteor shower, associated with the comet Encke. The Taurids are actually two separate showers, with a Southern and a Northern component. The Southern Taurids originated from Comet Encke, while the Northern Taurids originated from the asteroid 2004 TG10, possibly a large fragment of Encke due to its similar orbital parameters. They are named after their radiant point in the constellation Taurus, where they are seen to come from in the sky. Because of their occurrence in late October and early November, they are also called Halloween fireballs.
The Andromedids meteor shower is associated with Biela's Comet, the showers occurring as Earth passes through old streams left by the comet's tail. The comet was observed to have broken up by 1846; further drift of the pieces by 1852 suggested the moment of breakup was in either 1842 or early 1843, when the comet was near Jupiter. The breakup led to particularly spectacular showers in subsequent cycles.
The Virginids are a meteor shower. There are many major and minor meteor shower streams that occur during the Virginid Complex, including the Alpha Virginids, Gamma Virginids, Eta Virginids, Theta Virginids, Iota Virginids, Lambda Virginids, Mu Virginids, Pi Virginids, and Psi Virginids, and March Virginids, emanating mostly from the constellation Virgo between February and May. Collectively, the shower normally lasts from late January to mid-April and into early May, peaking in March and April, with one to two meteors per hour on average. The main radiant shifts southeastwards from central Leo in late January to central Virgo near Spica in mid-May.
The Alpha Monocerotids is a meteor shower active from 15 to 25 November, with its peak occurring on 21 or 22 November. The speed of its meteors is 65 km/s, which is close to the maximum possible speed for meteors of about 73 km/s. Normally it has a low Zenithal Hourly Rate (ZHR), but occasionally it produces much more intense meteor storms that last less than an hour: such outbursts were observed in 1925, 1935, 1985, and 1995. The 1925 and 1935 storms both reached levels passing 1,000 ZHR.
209P/LINEAR is a periodic comet discovered on 3 February 2004 by Lincoln Near-Earth Asteroid Research (LINEAR) using a 1.0-metre (39 in) reflector. Initially it was observed without a coma and named 2004 CB as a minor planet or asteroid, but in March 2004 Robert H. McNaught observed a comet tail which confirmed it as a comet. It was given the permanent number 209P on 12 December 2008 as it was the second observed appearance of the comet. Prediscovery images of the comet, dating back to December 2003, were found during 2009. Arecibo imaging in 2014 showed the comet nucleus is peanut shaped and about 2.4 km in diameter. The comet has extremely low activity for its size and is probably in the process of evolving into an extinct comet.
CAMS is a NASA-sponsored international project that tracks and triangulates meteors during night-time video surveillance in order to map and monitor meteor showers. Data processing is housed at the Carl Sagan Center of the SETI Institute in California, USA. Goal of CAMS is to validate the International Astronomical Union's Working List of Meteor Showers, discover new meteor showers, and predict future meteor showers.
References
- 1 2 3 4 5 6 7 Kronk, Gary W (2014). Meteor Showers: An Annotated Catalog (2nd ed.). Springer. pp. 61–63. ISBN 978-1-4614-7896-6 . Retrieved 28 August 2015.
- 1 2 3 Lunsford, Robert. "Meteor Activity Outlook for March 21-27, 2015". American Meteor Society. Archived from the original on 8 September 2015. Retrieved 28 August 2015.