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Comet of the Year 46P/Wirtanen arriving December 2018

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Comet 46P/Wirtanen is an icy small Solar System body that, when passing close to the Sun, will warm and begin to release gases, a process called outgassing. This produces a visible atmosphere or coma, and also a tail. These phenomena are due to the effects of solar radiation and the solar wind acting upon the nucleus of the comet. However, this time around, the ion tail will be pointing  away from the Earth and difficult to see due to the geometry. It will hopefully improve as the comet approaches perihelion (Dec 12) and perigee (Dec 16).



The Comet 46P/Wirtanen nucleus is approximately 1.2 kilometers diameter (example distance shown above) and is composed of loose collections of ice, dust, and small rocky particles. Although actual sizes are yet to be determined, the coma may be up to 15 times the Earth's diameter, while the tail may stretch one astronomical unit. Expected to be sufficiently bright, Comet 46P Wirtanen  may be seen from the Earth without the aid of a telescope and m…

Know the astronomical phenomena that we can enjoy in 2018

Comet 46P / Wirtanen, discovered in 1948 by the American astronomer Carl Alvar Wirtanen, takes 5.4 years to travel its orbit around the Sun. On December 12 it will make its closest approach to the Sun and four or five days later it will make its closest approach to our planet and it will appear between the Pleiades and the Hyades. It will approach about 30 lunar distances and could be observed with the naked eye. 

http://www.rguama.icrt.cu/conoce-los-fenomenos-astronomicos-que-podremos-disfrutar-en-el-2018/


December 12-16, 2018

On December 12, 2018 Comet 46P/Wirtanen will pass the sun at it's closest distance of 157,878,113 Kilometers (98,100,911 Miles).  Just four days later, on December 16, 2018 it will come closest to Earth at 11,622,258 Kilometers (7,221,736 Miles).  On it's closest approach, it's expected to reach naked-eye brightness.

Ephemeris

Ephemeris From Wikipedia, the free encyclopedia In astronomy and celestial navigation, an ephemeris (plural: ephemerides; from Latinephemeris, meaning 'diary', from Greek εφημερίς (ephemeris), meaning 'diary, journal' [1][2][3][4]) gives the positions of naturally occurring astronomical objects as well as artificial satellites in the sky at a given time or times. Historically, positions were given as printed tables of values, given at regular intervals of date and time. Modern ephemerides are often computed electronically from mathematical models of the motion of astronomical objects and the Earth. Even though the calculation of these tables was one of the first applications of mechanical computers, printed ephemerides are still produced, as they are useful when computational devices are not available. The astronomical position calculated from an ephemeris is given in the spherical polar coordinate system of right ascension and declination. Some of the astronomical ph…
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