Science
15 Oct 15
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18 Oct 15
Originally posted by joe shmo
I'm not really use to solving problems involving these distances,and light, etc. but to me it seems to be pretty standard trigonometry with the assumptions I made so I'll try, perhaps someone can confirm or refute the model.
D = diameter of the star
d = diameter of the planet
x = distance from the star to the earth
x' = distance from the star to the p ...[text shortened]... f the planet from the sun to block P percent of the light to the earth should pop out...I think.
(2) the Earths diameter is much smaller than the star such that the earth can be modeled as a point.
More to the point, the telescope used to make the observation is best modelled as a point 😉
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18 Oct 15
1 edit
Originally posted by googlefudgeGood point! However, I did preface this analysis with the statement that basically said I'm not used to thinking in space...so take it easy on me. 😞 😉(2) the Earths diameter is much smaller than the star such that the earth can be modeled as a point.
More to the point, the telescope used to make the observation is best modelled as a point 😉
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18 Oct 15
2 edits
I goofed the algebra up a bit...Woops!
D' = Sqrt(100/P)*d...........NOT d/(Sqrt(100/P)
x' = x*(d*(Sqrt(100/P ))/(D - d*(Sqrt( 100/P )))+1)^(-1)
And actually looking at the triangle again there is a tidier form:
x' = x*( 1 - Sqrt(100/P)*d/D )
Sorry!
I plugged in the numbers. I get 1265 LY from the star for a Jupiter sized planet that blocks 20% of the light.
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19 Oct 15
Originally posted by joe shmoWithout doing the math, that's the kind of result I was expecting.
I goofed the algebra up a bit...Woops!
[b]D' = Sqrt(100/P)*d...........NOT d/(Sqrt(100/P)
x' = x*(d*(Sqrt(100/P ))/(D - d*(Sqrt( 100/P )))+1)^(-1)
And actually looking at the triangle again there is a tidier form:
x' = x*( 1 - Sqrt(100/P)*d/D )
Sorry!
I plugged in the numbers. I get 1265 LY from the star for a Jupiter sized planet that blocks 20% of the light.[/b]
Bearing in mind that there was another massive dip ~15% prior to the ~22% one,
This explanation would require two random planets hundreds/thousands of LY away
from the star to just happen to pass exactly between us and this star in short succession.
And that this star just happens to also have a whole bunch of other weirdness going on.
.......
This is not a viable explanation.
19 Oct 15
Originally posted by joe shmoThat seems like a very large distance, I would have thought it would do that job a lot closer to the star, couple of light years maybe.
I goofed the algebra up a bit...Woops!
[b]D' = Sqrt(100/P)*d...........NOT d/(Sqrt(100/P)
x' = x*(d*(Sqrt(100/P ))/(D - d*(Sqrt( 100/P )))+1)^(-1)
And actually looking at the triangle again there is a tidier form:
x' = x*( 1 - Sqrt(100/P)*d/D )
Sorry!
I plugged in the numbers. I get 1265 LY from the star for a Jupiter sized planet that blocks 20% of the light.[/b]
Originally posted by sonhouseSuppose an observer were at just the right distance (L) from the sun (having radius R) so that Jupiter (at a distance l from the observer, and with radius r) just completely eclipses it
That seems like a very large distance, I would have thought it would do that job a lot closer to the star, couple of light years maybe.
R/r = L/l ~ 10.
So to completely block out the light from this star (assume it has the same radius as the sun) our Jupiter sized planet would need to be ~45 parsecs away (and very far from the star ~400 parsecs). To block out 25% of the light we need the apparent width to be half of the stars which puts the planet closer to the star by a factor of 2, so the planet would need to be 90 parsecs away. Or in light years ~300 ly from us and ~1180 from the star.
This is entirely implausible as an explanation. You'd need a family of different sized planetary sized objects drifting between us and the star without occluding any other stars. Just one won't do because the reduction in light intensity is aperiodic, but nevertheless repeating. If it only happened once one might put it down to that, but not repeatedly.
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19 Oct 15
Originally posted by DeepThoughtThe one caveat to these numbers is of course that an object could be closer to us but only
Suppose an observer were at just the right distance (L) from the sun (having radius R) so that Jupiter (at a distance l from the observer, and with radius r) just completely eclipses it
R/r = L/l ~ 10.
So to completely block out the light from this star (assume it has the same radius as the sun) our Jupiter sized planet would need to be ~45 parsec ...[text shortened]... rtheless repeating. If it only happened once one might put it down to that, but not repeatedly.
partially eclipse the star, and thus these numbers give only an upper limit on the distance
from us [or, if you prefer, a lower limit on distance from the target star] or [with similar effect]
be smaller than a Jupiter sized planet, but MUCH closer to us.
There would be some lower limit on how close it could be, before these objects would be visible
to Kepler and would be detected already, but that's more involved a calculation than I'm inclined
to do as this 'solution' has already been adequately refuted.
19 Oct 15
Originally posted by googlefudgePlus, the occulting planet would not block the star for very long, maybe only a few minutes.
The one caveat to these numbers is of course that an object could be closer to us but only
partially eclipse the star, and thus these numbers give only an upper limit on the distance
from us [or, if you prefer, a lower limit on distance from the target star] or [with similar effect]
be smaller than a Jupiter sized planet, but MUCH closer to us.
...[text shortened]... a calculation than I'm inclined
to do as this 'solution' has already been adequately refuted.
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19 Oct 15
Just to be clear...we are agreeing that the developed equation produces reasonable results, but the results are not a reasonable explanation of the observations? My only intention was to answer sonhouse's question, not form an opinion on whether or not it is a reasonable explanation for the phenomenon.
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19 Oct 15
Originally posted by joe shmoYes. 🙂
Just to be clear...we are agreeing that the developed equation produces reasonable results, but the results are not a reasonable explanation of the observations? My only intention was to answer sonhouse's question, not form an opinion on whether or not it is a reasonable explanation for the phenomenon.
20 Oct 15
Originally posted by googlefudgeAs a general point you are clearly right, but in this specific case I don't think that'll work. See figures 6 and 7 in the paper. In figure 6 the star has a "distinct protrusion to the left (east)"; in figure 7 this is shown, after much signal processing, as a separate star, with KIC 8462852 looking symmetric. I think they could probably tell if a large object were occluding it closer than that distance.
The one caveat to these numbers is of course that an object could be closer to us but only
partially eclipse the star, and thus these numbers give only an upper limit on the distance
from us [or, if you prefer, a lower limit on distance from the target star] or [with similar effect]
be smaller than a Jupiter sized planet, but MUCH closer to us.
...[text shortened]... a calculation than I'm inclined
to do as this 'solution' has already been adequately refuted.
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20 Oct 15
Originally posted by DeepThoughtI think you misunderstand me, probably I wasn't clear.
As a general point you are clearly right, but in this specific case I don't think that'll work. See figures 6 and 7 in the paper. In figure 6 the star has a "distinct protrusion to the left (east)"; in figure 7 this is shown, after much signal processing, as a separate star, with KIC 8462852 looking symmetric. I think they could probably tell if a large object were occluding it closer than that distance.
My point was that the occluding object could be closer to US if it were smaller and/or if
it were only partially eclipsing the target star, and thus the distance you estimated for
where a Jupiter sized occluding object would be is a limit and not a point.
As in it could be closer to us, but couldn't be further away.
As if it were further away it would have to be physically much larger than Jupiter, and the
only objects significantly larger than Jupiter are stars, and would be visible to us.
20 Oct 15
Originally posted by googlefudgeI had to look that up, yes, although the theoretical prediction and measured values are slightly different. The theoretical prediction is that Jupiter is only slightly below the upper radius limit. The measured maximum is about 1.5x the radius - see figure 4 on page 22 of [1] and I was looking at a log scale so that's a bit of a guess. Other than not being a viable explanation it would be quite interesting if there were an occluding object - since it would, as far as I know, be the first observed object not associated with a star.
I think you misunderstand me, probably I wasn't clear.
My point was that the occluding object could be closer to US if it were smaller and/or if
it were only partially eclipsing the target star, and thus the distance you estimated for
where a Jupiter sized occluding object would be is a limit and not a point.
As in it could be closer to us, but c ...[text shortened]... and the
only objects significantly larger than Jupiter are stars, and would be visible to us.
[1] http://arxiv.org/pdf/0707.2895v1.pdf