I collect star atlases, and I also spend a lot of time looking at astrophotography. I can’t help but notice that the randomly distributed stars on both charts and imagery occasionally seem to be organized into lines, rings and curved chains. Sometimes this effect is quite striking, and one can’t help but wonder if these features aren’t just chance artifacts, but real features caused by some physical process in stellar evolution or dynamics.

I am not the only one to notice this. In the introduction of a book I recently purchased, Craig Crossen, makes the following comment:

“The Night Sky Observer’s Guide”, Vol 1, pg xxxiii, G.R. Kepple, G.W. Sanner, Willmann-Bell Inc.

“Finally, the stars in many open clusters are distributed in chains, often arcing around conspicuous, nearly starless voids, that are so long and regular they can hardly be accidental but must have been the consequence of some physical condition–perhaps a magnetic field?–in the giant molecular cloud where the cluster formed. Some of the more striking star chains are in…”

(and here, the author lists a set of open clusters as examples). I have provided a link to an image of the first) You may Google the others and see for yourself. Use the words “open cluster” in your query to help avoid similarly named objects.

http://scienceblogs.com/startswithabang/files/2013/04/ngc19.jpeg

open cluster M38

M41
M50
NGC 2301
M93
NGC 6866
NGC 6603
NGC 2252
Collinder 104

These lines, rings and chains are not limited to clusters, as I mentioned above, you see them in star charts and astrophotos of random selected star fields, such as the Palomar Observatory Sky Survey plates. We all know the human visual system is exquisitely tuned to detect patterns, so sensitive in fact, that we often tend to see them where none actually exist! But surely this visual evidence suggests that maybe there is some physical phenomenon at work here, not just a quirk of human image processing and pattern recognition. When you look at data, you see (or imagine!) patterns, whether they be in stellar cartography, fossil evidence for evolution, AGW graphs, firearms statistics, racial characteristics or legislative gerrymandering. We tend to cherry-pick, because we are apes and apes eat fruit. If it even faintly resembles a fruit, we take a second look. And not only do we see patterns where there are none, we also tend to remember and assign more weight to those that reinforce our preconceptions and biases.

Fortunately, astronomers are quite aware of this phenomenon, having been bitten by it numerous times in the past. Cherry-picked lines of stars are no exception. The following monograph takes a good look at this, and its bibliography attests to the fact that I am not the first to notice it. Of course, none of this rules out that perhaps some stellar rings and chains may be real, we just cannot declare they must definitely be so.

http://articles.adsabs.harvard.edu/full/seri/A+A../0041//0000355.000.html