Comments on: Naked Eye Comet http://www.slackerastronomy.org/wordpress/2007/10/naked-eye-comet/ If you aren't going to care about something, may as well not care about astronomy Wed, 03 Dec 2008 22:26:29 +0000 http://wordpress.org/?v=2.6.3 By: Kevin http://www.slackerastronomy.org/wordpress/2007/10/naked-eye-comet/#comment-172228 Kevin Sun, 28 Oct 2007 12:52:48 +0000 http://www.slackerastronomy.org/wordpress/index.php/archive/naked-eye-comet/#comment-172228 From what I've read, this comet had outbursts before, but nothing as great as the current apparition. We showed it off to the public last night at our observatory's open house, and by the time we left you could easily see that it was non-stellar even to the naked-eye. From what I’ve read, this comet had outbursts before, but nothing as great as the current apparition.

We showed it off to the public last night at our observatory’s open house, and by the time we left you could easily see that it was non-stellar even to the naked-eye.

]]> By: michael http://www.slackerastronomy.org/wordpress/2007/10/naked-eye-comet/#comment-171236 michael Fri, 26 Oct 2007 04:59:07 +0000 http://www.slackerastronomy.org/wordpress/index.php/archive/naked-eye-comet/#comment-171236 <blockquote>The active areas spew gas and dust into space resulting in a luminous volume far more effective at scattering light than the tiny (and usually very dark) nuclear surface of the comet</blockquote> Still, if we assume that this wasn't happening before and it is happening now and that the light is all reflected (i.e. no change in temperature) then we are seeing an increase in effective surface area, aren't we? And perhaps a change in albedo.

The active areas spew gas and dust into space resulting in a luminous volume far more effective at scattering light than the tiny (and usually very dark) nuclear surface of the comet

Still, if we assume that this wasn’t happening before and it is happening now and that the light is all reflected (i.e. no change in temperature) then we are seeing an increase in effective surface area, aren’t we? And perhaps a change in albedo.

]]> By: dougwelch http://www.slackerastronomy.org/wordpress/2007/10/naked-eye-comet/#comment-170936 dougwelch Thu, 25 Oct 2007 13:59:27 +0000 http://www.slackerastronomy.org/wordpress/index.php/archive/naked-eye-comet/#comment-170936 This is also an unusual event in that the comet never gets all that close to the Sun. Its maximum distance from the Sun is 5.2 AU (Jupiter-ish) and its minimum distance is 2.2 AU (outside the orbit of Mars). Since it has apparently done this before, it may be an out-gassing event instead of a break-up - we'll know more soon! This is also an unusual event in that the comet never gets all that close to the Sun. Its maximum distance from the Sun is 5.2 AU (Jupiter-ish) and its minimum distance is 2.2 AU (outside the orbit of Mars). Since it has apparently done this before, it may be an out-gassing event instead of a break-up - we’ll know more soon!

]]> By: dougwelch http://www.slackerastronomy.org/wordpress/2007/10/naked-eye-comet/#comment-170934 dougwelch Thu, 25 Oct 2007 13:53:33 +0000 http://www.slackerastronomy.org/wordpress/index.php/archive/naked-eye-comet/#comment-170934 The brightness of a comet usually depends on the activity from certain spots on its surface. These spots generally are a small fraction of the surface area. When a comet breaks up, it exposes a huge amount of active surface at once. The active areas spew gas and dust into space resulting in a luminous volume far more effective at scattering light than the tiny (and usually very dark) nuclear surface of the comet. The brightness of a comet usually depends on the activity from certain spots on its surface. These spots generally are a small fraction of the surface area. When a comet breaks up, it exposes a huge amount of active surface at once.

The active areas spew gas and dust into space resulting in a luminous volume far more effective at scattering light than the tiny (and usually very dark) nuclear surface of the comet.

]]> By: michael http://www.slackerastronomy.org/wordpress/2007/10/naked-eye-comet/#comment-170839 michael Thu, 25 Oct 2007 03:58:52 +0000 http://www.slackerastronomy.org/wordpress/index.php/archive/naked-eye-comet/#comment-170839 <blockquote>This almost certainly indicates that the nucleus has split into several pieces. </blockquote> This may be naive, but if L2/L1=400,000 and the luminosity is proportional to R^2 then the new radius R2=R1*sqrt(400000)=R1*600. So the nucleus got 600 times bigger?

This almost certainly indicates that the nucleus has split into several pieces.

This may be naive, but if L2/L1=400,000 and the luminosity is proportional to R^2 then the new radius R2=R1*sqrt(400000)=R1*600. So the nucleus got 600 times bigger?

]]> By: michael http://www.slackerastronomy.org/wordpress/2007/10/naked-eye-comet/#comment-170837 michael Thu, 25 Oct 2007 03:53:40 +0000 http://www.slackerastronomy.org/wordpress/index.php/archive/naked-eye-comet/#comment-170837 I took a look tonight. It looked non-stellar to me and about V=3 or so. It looked redder than Delta Persei (which is quite a blue star at B-V=-0.12). I took a look tonight. It looked non-stellar to me and about V=3 or so. It looked redder than Delta Persei (which is quite a blue star at B-V=-0.12).

]]> By: dougwelch http://www.slackerastronomy.org/wordpress/2007/10/naked-eye-comet/#comment-170676 dougwelch Wed, 24 Oct 2007 21:30:57 +0000 http://www.slackerastronomy.org/wordpress/index.php/archive/naked-eye-comet/#comment-170676 This almost certainly indicates that the nucleus has split into several pieces. If so, there may be even more activity in the next while. This almost certainly indicates that the nucleus has split into several pieces. If so, there may be even more activity in the next while.

]]>