Radiation astronomy/Showers

From Wikiversity
Jump to navigation Jump to search

Meteors may occur in showers, which arise when the Earth passes through a trail of debris left by a comet, or as "random" or "sporadic" meteors, not associated with a specific single cause. A number of specific meteors have been observed, largely by members of the public and largely by accident, but with enough detail that orbits of the meteoroids producing the meteors have been calculated. All of the orbits passed through the asteroid belt.[1]

Alpha-Monocerotid meteor showers[edit]

This picture is of the Alpha-Monocerotid meteor outburst in 1995. It is a timed exposure where the meteors have actually occurred several seconds to several minutes apart. Credit: NASA Ames Research Center/S. Molau and P. Jenniskens.

Eta Aquarid meteor showers[edit]

"At 66 kilometers (41 miles) per second, they appear as fast streaks, faster by a hair than their sisters, the Eta Aquarids of May. And like the Eta Aquarids, the brightest of family tend to leave long-lasting trains. Fireballs are possible three days after maximum."[2]

Geminids[edit]

Leonid meteor showers[edit]

The photograph shows the meteor, afterglow, and wake as distinct components of a meteor during the peak of the 2009 Leonid Meteor Shower. Credit: Navicore.
This photograph shows the Leonids as many begin contacting the Earth's atmosphere. Credit: NASA.

"The Leonid meteor shower peaked early Saturday (Nov. 17 [2012]), and some night sky watchers caught a great view. The Leonids are a yearly meteor display of shooting stars that appear to radiate out of the constellation Leo. They are created when Earth crosses the path of debris from the comet Tempel-Tuttle, which swings through the inner solar system every 33 years."[3]

Orionid meteor showers[edit]

"The Orionid meteor shower [leftover bits of Halley's Comet] is scheduled to reach its maximum before sunrise on Sunday morning (Oct. 21 [2012]). This will be an excellent year to look for the Orionids, since the moon will set around 11 p.m. local time on Saturday night (Oct. 20) and will not be a hindrance at all ... The orbit of Halley's Comet closely approaches the Earth's orbit at two places. One point is in the early part of May producing a meteor display known as the Eta Aquarids. The other point comes in the middle to latter part of October, producing the Orionids."[4]

Perseid meteor showers[edit]

The Perseid meteor shower, usually the richest meteor shower of the year, peaks in August. Over the course of an hour, a person watching a clear sky from a dark location might see as many as 50-100 meteors. Most meteors are actually pieces of rock that have broken off a comet and continue to orbit the Sun. The Earth travels through the comet debris in its orbit. As the small pieces enter the Earth's atmosphere, friction causes them to burn up.

Quadrantids[edit]

The Quadrantids (QUA) are a January meteor shower, with the zenithal hourly rate (ZHR) of this shower as high as that of two other reliably rich meteor showers, the Perseids in August and the Geminids in December.[5]

The meteor rates exceed one-half of their highest value for only about eight hours (compared to two days for the August Perseids), which means that the stream of particles that produces this shower is narrow, and apparently deriving within the last 500 years from some orbiting body.[6] The parent body of the Quadrantids was tentatively identified in 2003[7] as the minor planet (196256) 2003 EH1, which in turn may be related to the comet C/1490 Y1[8] that was observed by Chinese, Japanese and Korean astronomers some 500 years ago.

References[edit]

  1. Diagram 2: the orbit of the Peekskill meteorite along with the orbits derived for several other meteorite falls. Uregina.ca. Retrieved 2011-09-16.
  2. David Levy and Stephen Edberg. Observe: Meteors. Astronomical League. |access-date= requires |url= (help)
  3. Clara Moskowitz (November 17, 2012). Amazing Leonid Meteor Shower Photos Captured By Stargazers. SPACE.com. Retrieved 2012-11-18.
  4. Joe Rao (October 19, 2012). Orionid Meteor Shower Spawned by Halley's Comet Peaks This Weekend. SPACE.com. Retrieved 2012-10-19.
  5. "Does the published meteor rate for a shower really represent what I should expect to see?". American Meteor Society. Retrieved 2012-12-29.
  6. "Stellar Meteor Shower Jan. 3". Space.com. Retrieved 2009-01-03.
  7. Peter Jenniskens (Dec 8, 2003). "2003 EH1 is the Quadrantid shower parent comet". The Ephemeris (San Jose Astronomical Association newsletter). Retrieved 2004-12-17.
  8. Jenniskens, Peter (2004). "2003 EH1 Is the Quadrantid Shower Parent Comet". The Astronomical Journal 127 (5): 3018–3022. doi:10.1086/383213. 

External links[edit]