KBO encounters |
KBO encounters |
Aug 2 2008, 12:53 PM
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#501
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Newbie Group: Members Posts: 6 Joined: 1-August 08 Member No.: 4280 |
Hi,
I’m regular follower of NH and I’m also interested in the 2nd leg of the mission, i.e the 2016+ KBOs encounters. Does anyone know when operations about this leg (starting with searching objects of interest with HST or some other earth-based means, I suppose) are expected to begin ? |
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Feb 4 2019, 06:59 PM
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#502
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Senior Member Group: Members Posts: 3516 Joined: 4-November 05 From: North Wales Member No.: 542 |
Can you elaborate on the statement 'Individual stars co-align'? Do you mean that we see mutual eclipses of random pairs of stars in these star clouds? I was not aware of this and would find it very surprising if true. My understanding has been that the apparent crowding of stars in images such as the one you post has to do mainly with each star appearing enlarged by diffraction and other effects. As to background illumination from dust and gas, surely a putative KBO a few km across would not be observable in silhouette against this ???
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Feb 5 2019, 03:55 PM
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#503
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
Can you elaborate on the statement 'Individual stars co-align'? Do you mean that we see mutual eclipses of random pairs of stars in these star clouds? I was not aware of this and would find it very surprising if true. ... In rare cases, stars are so perfectly co-aligned (sysygy), that you get gravitational microlensing effects, like Einstein rings. But I think, that's rare enough to be neglected here. Other, almost co-aligned stars usually can be distinguished by their spectra, if sufficiently bright. There exist also spectrometers for amateur astronomy. But I think, that it would be very hard to resolve any spectra of very faint stars in a real time scenario. In the aftermath, it might be possible to resolve ambiguities. --- Back to JRehling's scenario: A dark foreground object crossing a background galaxy would be an extreme case of occulting many stars at a time. But I doubt, that it would be noticed at all due to the almost constant mean brightness. A globular cluster in the Milky Way may be a better example of a finite number of stars that can be occulted at a time, but with discrete jumps of brightness within a pixel. |
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