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Phoenicids
The Phoenicids are a minor meteor shower, first noticed by observers in New Zealand, Australia, the Indian Ocean, and South Africa during an outburst of approximately 100 meteors an hour that occurred during December 1956. Like other meteor showers, the Phoenicids get their name from the location of their radiant, which is in the constellation Phoenix. They are active from 29 November to 9 December, with a peak occurring around 5/6 December each year, and are best seen from the Southern Hemisphere. The Phoenicids appear to be associated with a stream of material from the disintegrating comet 289P/Blanpain (D/1819 W1) with a 5-year orbital period. It next comes to perihelion in 2025. Using the formula V_\infty = \sqrt, the Phoenicids (#254) have an atmospheric entry velocity of about 14.3 km/s and a geocentric velocity (before the influence of Earth's gravity) of 8.9 km/s. A very minor meteor shower with a radiant in Phoenix also occurs in July; this shower is referred to as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
289P/Blanpain
289P/Blanpain, formerly D/1819 W1 (Blanpain) is a short-period comet with an orbital period of 5.2 years. It was discovered by Jean-Jacques Blanpain on November 28, 1819 but was considered lost until it was recovered in 2013. It was last observed in 2020. Observational history The comet was discovered by Jean-Jacques Blanpain on November 28, 1819. Blanpain described the comet as having a "very small and confused nucleus". Another independent discovery was made on December 5 of that year by J. L. Pons. Following this the comet was lost, and was given the designation 'D' (Disappeared or Dead). However, in 2003, the orbital elements of newly discovered asteroid were calculated by Marco Micheli and others to be a probable match for the lost comet. On 12 December 2003, it approached Earth at a distance of . Further observations of the asteroid in 2005 by David Jewitt using the University of Hawaii 2.2 m telescope on Mauna Kea, appeared to reveal a faint coma, which supports th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phoenix (constellation)
Phoenix is a minor constellation in the southern sky. Named after the mythical Phoenix (mythology), phoenix, it was first depicted on a celestial atlas by Johann Bayer in his 1603 ''Uranometria''. The French explorer and astronomer Nicolas Louis de Lacaille charted the brighter stars and gave their Bayer designations in 1756. The constellation stretches from roughly −39° to −57° declination, and from 23.5h to 2.5h of right ascension. The constellations Phoenix, Grus (constellation), Grus, Pavo (constellation), Pavo and Tucana, are known as the Southern Birds. The brightest star, Alpha Phoenicis, is named Ankaa, an Arabic word meaning 'the Phoenix'. It is an orange giant of apparent magnitude 2.4. Next is Beta Phoenicis, actually a Binary star, binary system composed of two yellow giants with a combined apparent magnitude of 3.3. Nu Phoenicis has a dust disk, while the constellation has ten star systems with known planets and the recently discovered galaxy clusters El Gord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteor Shower
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. Historical developments A meteor shower in August 1583 was recorded in the Timbuktu manuscripts.Abraham, Curtis"Stars of the Sahara" ''New Scientist'', issue 2617,15 August 2007, page 39–41 I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
November
November is the eleventh and penultimate month of the year in the Julian and Gregorian calendars. Its length is 30 days. November was the ninth month of the calendar of Romulus . November retained its name (from the Latin ''novem'' meaning "nine") when January and February were added to the Roman calendar. November is a month of late spring in the Southern Hemisphere and late autumn in the Northern Hemisphere. Therefore, November in the Southern Hemisphere is the seasonal equivalent of May in the Northern Hemisphere and vice versa. In Ancient Rome, Ludi Plebeii was held from November 4–17, Epulum Jovis was held on November 13 and Brumalia celebrations began on November 24. These dates do not correspond to the modern Gregorian calendar. November was referred to as Blōtmōnaþ by the Anglo-Saxons. Brumaire and Frimaire were the months on which November fell in the French Republican calendar. Astronomy November meteor showers include the Andromedids, which occurs fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiant (meteor Shower)
The radiant or apparent radiant of a meteor shower is the celestial point in the sky from which (from the point of view of a terrestrial observer) the paths of meteors appear to originate. The Perseids, for example, are meteors which appear to come from a point within the constellation of Perseus. Meteor paths appear at random locations in the sky, but the apparent paths of two or more meteors from the same shower will diverge from the radiant. The radiant is the vanishing point of the meteor paths, which are parallel lines in three-dimensional space, as seen from the perspective of the observer, who views a two-dimensional projection against the sky. The geometric effect is identical to crepuscular rays, where parallel sunbeams appear to diverge. A meteor that does not point back to the known radiant for a given shower is known as a ''sporadic'' and is not considered part of that shower. Shower meteors may appear a short time before the radiant has risen in the observer's ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perihelion
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides pertaining to orbits around different bodies have distinct names to differentiate themselves from other apsides. Apsides pertaining to geocentric orbits, orbits around the Earth, are at the farthest point called the ''apogee'', and at the nearest point the ''perigee'', like with orbits of satellites and the Moon around Earth. Apsides pertaining to orbits around the Sun are named ''aphelion'' for the farthest and ''perihelion'' for the nearest point in a heliocentric orbit. Earth's two apsides are the farthest point, ''aphelion'', and the nearest point, ''perihelion'', of its orbit around the host Sun. The terms ''aphelion'' and ''perihelion'' apply in the same way to the orbits of Jupiter and the other planets, the comets, and the asteroids of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Entry
Atmospheric entry (sometimes listed as Vimpact or Ventry) is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. Atmospheric entry may be ''uncontrolled entry,'' as in the entry of astronomical objects, space debris, or bolides. It may be ''controlled entry'' (or ''reentry'') of a spacecraft that can be navigated or follow a predetermined course. Methods for controlled atmospheric ''entry, descent, and landing'' of spacecraft are collectively termed as ''EDL''. Objects entering an atmosphere experience atmospheric drag, which puts mechanical stress on the object, and aerodynamic heating—caused mostly by compression of the air in front of the object, but also by drag. These forces can cause loss of mass ( ablation) or even complete disintegration of smaller objects, and objects with lower compressive strength can explode. Objects have reentered with speeds ranging from 7.8 km/s for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Meteor Society
The American Meteor Society, Ltd. (AMS) is a non-profit scientific organization established to encourage and support the research activities of both amateur and professional astronomers who are interested in the field of meteor astronomy. Its affiliates observe, monitor, collect data on, study, and report on meteors, meteor showers, meteoric fireballs, and related meteoric phenomena. The society publishes observations and scientific interpretations quarterly in '' Meteor Trails, The Journal of American Meteor Society''. Once per year they give the '' American Meteor Society Award'' to a person who has contributed to research on meteors. They also provide an annual research grant to a student of SUNY-Geneseo who has contributed to meteor research or to the AMS. History The society was founded in 1911 by Charles P. Olivier of the Leander McCormick Observatory. The initial enrollment was fifteen members. These were recruited by Olivier by letter. The first paper based on the obs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
July
July is the seventh month of the year in the Julian calendar, Julian and Gregorian calendars. Its length is 31 days. It was named by the Roman Senate in honour of Roman general Julius Caesar in 44 B.C., being the month of his birth. Before then it was called Quintilis, being the fifth month of the calendar that started with March. It is on average the warmest month in most of the Northern Hemisphere, where it is the second month of summer, and the coldest month in much of the Southern Hemisphere, where it is the second month of winter. The second half of the year commences in July. In the Southern Hemisphere, July is the seasonal equivalent of January in the Northern hemisphere. "Dog days" are considered to begin in early July in the Northern Hemisphere, when the hot sultry weather of summer usually starts. Lamb and mutton#Classifications, Spring lambs born in late winter or early spring are usually sold before 1 July. Symbols July's birthstone is the ruby, which symbolizes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
