StarWatch 900 for the week of November 17, 2013
By Gary Becker
The next few weeks hold the promise of becoming one of the great observational periods for astronomy in the 21st century.
That may seem too great a claim to be made this early in just 2013, but astronomers have been watching Comet ISON rapidly brighten as it heads inward towards a Thanksgiving Day encounter with the sun.
ISON stands for the International Scientific Optical Network located near Kislovodsk, a spa city between the Black Sea and Caspian Sea.
Using a 16-inch reflector on September 21, 2012, Vitali Nevski of Belarus and Artyom Novichonok of Russia first imaged the interloper, but prediscovery photos were found to exist as far back as late November of 2011.
What makes Comet ISON so interesting is that it is a sungrazer. It will pass the sun at only 724,000 miles from its surface, causing the sun’s energy to “boil” away a substantial amount of itself in the days prior to and after its closest approach.
There are two possible scenarios to the ISON’s story.
One is the comet will simply evaporate in the hellish million degree environs of the sun’s corona because the nucleus of ISON, the origin point for the tails and other features which a comet possesses, is not very big, only three quarters of a mile in diameter at its greatest, according to Hubble and Spitzer Space Telescope measurements.
If the comet disintegrates, we see nothing.
Situation two is that ISON makes it around the sun and into our northern hemispheric morning sky.
On November 29 around dawn, the ESE may have a long gossamer spike projecting up from the horizon, the tail of a great comet.
The head of ISON should become completely visible about an hour before dawn between the 4th and 6th of December.
By Christmas, ISON will be visible all night, much higher in the sky, but much diminished in brightness; but still probably an object visible to the unaided eye.
More about ISON next week…
By Gary Becker
The next few weeks hold the promise of becoming one of the great observational periods for astronomy in the 21st century.
That may seem too great a claim to be made this early in just 2013, but astronomers have been watching Comet ISON rapidly brighten as it heads inward towards a Thanksgiving Day encounter with the sun.
ISON stands for the International Scientific Optical Network located near Kislovodsk, a spa city between the Black Sea and Caspian Sea.
Using a 16-inch reflector on September 21, 2012, Vitali Nevski of Belarus and Artyom Novichonok of Russia first imaged the interloper, but prediscovery photos were found to exist as far back as late November of 2011.
What makes Comet ISON so interesting is that it is a sungrazer. It will pass the sun at only 724,000 miles from its surface, causing the sun’s energy to “boil” away a substantial amount of itself in the days prior to and after its closest approach.
There are two possible scenarios to the ISON’s story.
One is the comet will simply evaporate in the hellish million degree environs of the sun’s corona because the nucleus of ISON, the origin point for the tails and other features which a comet possesses, is not very big, only three quarters of a mile in diameter at its greatest, according to Hubble and Spitzer Space Telescope measurements.
If the comet disintegrates, we see nothing.
Situation two is that ISON makes it around the sun and into our northern hemispheric morning sky.
On November 29 around dawn, the ESE may have a long gossamer spike projecting up from the horizon, the tail of a great comet.
The head of ISON should become completely visible about an hour before dawn between the 4th and 6th of December.
By Christmas, ISON will be visible all night, much higher in the sky, but much diminished in brightness; but still probably an object visible to the unaided eye.
More about ISON next week…
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