Mystery Alignment of Planetary Nebulae Discovered

astroengine writes "Astronomers have discovered something weird in the Milky Way's galactic bulge — a population of planetary nebula are all mysteriously pointing in the same direction. They noticed the mysterious alignment in the long axes of bipolar planetary nebulae. 'This really is a surprising find and, if it holds true, a very important one,' said Bryan Rees of the University of Manchester, co-author of the paper (PDF) to appear in the journal Monthly Notices of the Royal Astronomical Society. 'Many of these ghostly butterflies appear to have their long axes aligned along the plane of our galaxy.' The team of astronomers, who used data from Hubble and the European Southern Observatory's New Technology Telescope (NTT) to survey 130 nebulae, posit that powerful magnetic fields may be behind the phenomenon."

Comments

Re:Bipolar planetary nebula

[CheshireDragon]

I too was thinking that the nebulae and myself have something in common.

Re:Why is that surprising?

[icebike]

Why is this surprising?

It makes sense that if all of the stars that formed the nebulae came from the same giant swirling cloud of gas, then the stars formed would tend to have angular momenta mostly aligned upon that same axis. When those stars explode later, the axis of the planetary nebula will be along this same axis.

Well first, you have to read the SUMMARY where you will find

a population of planetary nebula are all mysteriously pointing in the same direction.

(I will point out that "a population" is very vague, and could in fact refer to a very small subset.).

Then from TFA you see the actual quote:

However, a new study by astronomers from the University of Manchester, UK, now shows surprising similarities between some of these nebulae: many of them line up in the sky in the same way

So from SOME in the article, we get the implication of ALL (wrapped in weasel words) by the submitter, someone named "astroengine".
An unfortunate level of HYPE that we've come to find all too often in Slashdot.

Link to the paper in the article is incorrect

[IndigoZulu]

Correct paper: http://www.spacetelescope.org/static/archives/releases/science_papers/heic1316a.pdf

Link to preprint

[mdsolar]

Here is the preprint: http://adsabs.harvard.edu/abs/2013arXiv1307.5711R

We use high-resolution H {\alpha} images of 130 planetary nebulae (PNe) to investigate whether there is a preferred orientation for PNe within the Galactic Bulge. The orientations of the full sample have an uniform distribution. However, at a significance level of 0.01, there is evidence for a non-uniform distribution for those planetary nebulae with evident bipolar morphology. If we assume that the bipolar PNe have an unimodal distribution of the polar axis in Galactic coordinates, the mean Galactic position angle is consistent with 90{\deg}, i.e. along the Galactic plane, and the significance level is better than 0.001 (the equivalent of a 3.7{\sigma} significance level for a Gaussian distribution). The shapes of PNe are related to angular momentum of the original star or stellar system, where the long axis of the nebula measures the angular momentum vector. In old, low-mass stars, the angular momentum is largely in binary orbital motion. Consequently, the alignment of bipolar nebulae that we have found indicates that the orbital planes of the binary systems are oriented perpendicular to the Galactic plane. We propose that strong magnetic fields aligned along the Galactic plane acted during the original star formation process to slow the contraction of the star forming cloud in the direction perpendicular to the plane. This would have produced a propensity for wider binaries with higher angular momentum with orbital axes parallel to the Galactic plane. Our findings provide the first indication of a strong, organized magnetic field along the Galactic plane that impacted on the angular momentum vectors of the resulting stellar population.