Comments on: A dying star weaves a spiral in the night

By: Tea With Chris: 1/N’s Worth of Everything | Back to the World

Tea With Chris: 1/N’s Worth of Everything | Back to the World — Thu, 11 Oct 2012 22:52:46 +0000

[...] Two videos of space changing: Toronto expands, a star explodes. [...]

By: Matt B.

Matt B. — Thu, 11 Oct 2012 21:18:51 +0000

So we have only two examples of the spiral so far, right? And they both seem to be oriented pretty normal to us. So I’m guessing that a spiral would be difficult to discern if it’s far from normal. Otherwise it’s a big coincidence.

By: Lawrence

Lawrence — Thu, 11 Oct 2012 21:13:48 +0000

The explanation for all this is simple. We are watching an alien civilization constructing a Dyson sphere.

By: Jon Hanford

Jon Hanford — Thu, 11 Oct 2012 19:39:14 +0000

@Joseph G(7)

The HST image of LL Peg always reminds me of the (completely unrelated) dwarf “elliptical” galaxy IC 3328 in the Virgo galaxy cluster:

http://apod.nasa.gov/apod/ap000602.html

http://arxiv.org/pdf/astro-ph/0004248v1.pdf

By: Dustin

Dustin — Thu, 11 Oct 2012 17:59:27 +0000

@23 Luis C. – Thank you for adding the additional information. Seeing the 3d interpolation of the data is probably one of the most amazing things I have seen in a while. To actually give these astronomical objects real shape makes these wonders come alive. It sparks the imagination! Thank you and thank you Phil for sharing the wonders of our Universe with all of us,

By: Mattais

Mattais — Thu, 11 Oct 2012 15:12:42 +0000

Am I correct in my interpretation that you are using the doppler shift in the spectrum of each ALMA pixel to derive the 3d position of each point around the star?

/Mattias

By: Tara Li

Tara Li — Thu, 11 Oct 2012 14:35:42 +0000

@5 Jim – I know that looking at it, it’s not hard to see a spiral. My question is if actual mathematical curve-fitting was done to distinguish. After all, the BA-Man has shown us example after example of how the eye and the mind work together to create patterns that aren’t necessarily there.

By: Luis C.

Luis C. — Thu, 11 Oct 2012 08:30:24 +0000

@Phil (#6)
Just to clarify and avoid misunderstanding. These are indeed actual data, as you originally stated! But it is not a image as in the good old days where only CCDs roamed the skies… ALMA data are different and here they’ve been visualised in a slightly different way from how we normally treat a plain two-dimensional CCD picture. One of ALMA’s great strengths is that its observations also have a spectral (wavelength) dimension in addition to the “x” and “y” dimensions of RA and Dec. So for every “pixel” on the sky, we actually get a spectrum from that point, i.e. the dataset is a three-dimensional data cube rather than a two-dimensional image.

We wanted to show a three-dimensional view of the structure in the data, which you can see rotating in the top-left of the video at http://www.eso.org/public/videos/eso1239a/ . We rendered the data points using glowing particles in order to let the viewer see through the surface into this 3d structure. We also added a marker in the centre to represent the central star. The main image from our release, which you’ve shown above, is a 2d slice through this 3d rendering of the ALMA datacube. The short answer: yes, these are definitely real data and in no sense a “drawing”!

By: Messier Tidy Upper

Messier Tidy Upper — Thu, 11 Oct 2012 07:11:28 +0000

@ ^ Tara Li : Excellent – just what I was after! Thanks.

By: Tara Li

Tara Li — Thu, 11 Oct 2012 05:18:44 +0000

es.wikipedia.org has an article on R Sculptoris (Spanish, English translation by Google):

Sculptoris R (R Scl / HD 8879 / HR 423) is a variable star in the constellation of Sculptor . It is an interesting target for the amateur astronomer , combining a wide range of variability, excellent stars with which to compare and intense red.

At a distance of about 1550 light years , R Sculptoris is a carbon star of spectral type C6II. In these stars the carbon compounds allow passing blue light, so show an intense red. Large amount of material lost its outer layers through the stellar wind , in some of them there is a separate layer of gas and dust that surrounds them. Although generally dominated by a single temperature, some Sculptoris-R-like show evidence of a secondary cooler powdery component, which is manifested by an excess infrared remote. It is thought that this excess is due to the existence of a layer of dust removed from the star.

Sculptoris R is a semiregular variable star whose brightness varies between apparent magnitude +12.90 +9.10 and throughout a period of 370 days. The amplitude of the oscillation appears, however, variable.

Visually a 10 arcsec there a companion star of magnitude 11.9, which shares proper motion with R Sculptoris.