by JohnD » Sun May 19, 2013 4:32 pm
The very name "antitail" implies that this is a comet tail that appears to precede the comet in its orbit.
Previous comets have had antitails that were more obvious and anomalous than Pan STARRS'
This is difficult to understand, yet the explanation to this APOD offers only, "It shows the comet has developed an extensive anti-tail, dust trailing along the comet's orbit (to the left of the coma), stretching more than 3 degrees across the frame" "Trailing"? Then it must be behind the comet? I'm even more confused.
The "antitail" link to
http://www.daviddarling.info/encycloped ... itail.html which is almost as brief, "Part of the dust tail of a comet that seems to point, often like a spike, toward the Sun. This rare phenomenon is an illusion caused by the viewing geometry and typically occurs when Earth crosses the plane of a comet's orbit when the comet is relatively close to the Sun. Under these circumstances, the cometary dust, which lies in a thin sheet and lags behind the comet, may be seen edge-on as an antitail. One of the most prominent antitails ever seen was that of comet Arend-Roland during its perihelion passage in 1957."
For those of use without an insight into orbits and astronomical points of view, please may we have some better explanation of this apparently bizarre phenomenon? A diagram would be good!
Thanks
John
The very name "antitail" implies that this is a comet tail that appears to precede the comet in its orbit.
Previous comets have had antitails that were more obvious and anomalous than Pan STARRS'
This is difficult to understand, yet the explanation to this APOD offers only, "It shows the comet has developed an extensive anti-tail, dust trailing along the comet's orbit (to the left of the coma), stretching more than 3 degrees across the frame" "Trailing"? Then it must be behind the comet? I'm even more confused.
The "antitail" link to http://www.daviddarling.info/encyclopedia/A/antitail.html which is almost as brief, "Part of the dust tail of a comet that seems to point, often like a spike, toward the Sun. This rare phenomenon is an illusion caused by the viewing geometry and typically occurs when Earth crosses the plane of a comet's orbit when the comet is relatively close to the Sun. Under these circumstances, the cometary dust, which lies in a thin sheet and lags behind the comet, may be seen edge-on as an antitail. One of the most prominent antitails ever seen was that of comet Arend-Roland during its perihelion passage in 1957."
For those of use without an insight into orbits and astronomical points of view, please may we have some better explanation of this apparently bizarre phenomenon? A diagram would be good!
Thanks
John