Starship Asterisk*

ta152h0 wrote:
a spinning neutron star dragging " stuff " around ? There is stuff out there that cannot be detected ! Yet !

• No one said anything about "a neutron star."

https://en.wikipedia.org/wiki/IRAS_23166%2B1655 wrote:
<<IRAS 23166+1655 is thought to be a preplanetary nebula surrounding LL Pegasi (AFGL 3068), a binary system that includes an extreme carbon star. The pair is hidden by the dust cloud ejected from the carbon star and is only visible in infrared light.

The nebula displays an unusual spiral shape. The shape is thought to be formed through the interaction between the stellar companion and the carbon star, as has been seen in other binary systems, although not with such a precise geometric form. The distance between spiral layers is consistent with estimates of the pair's orbital period based on their apparent angular separation. Some say that, due to the regular appearance of spiral arms, the orbital period between LL Pegasi A (IRAS 23166+1655 A) and LL Pegasi B (IRAS 23166+1655 B) have an orbital period of c. 800 years.>>

• indicative of yet a third star

Ann wrote:LL Pegasi is a very interesting object. Amazingly, its spiral has made at least four turns around the center. I can't think of any galaxy that does anything remotely similar.

Chris Peterson wrote:

Ann wrote:LL Pegasi is a very interesting object. Amazingly, its spiral has made at least four turns around the center. I can't think of any galaxy that does anything remotely similar.

Of course, there is no reason to make any association between this object and galaxies. Other than a superficial resemblence, the underlying mechanism creating the spiral is entirely different. In this nebula, the material that makes up the spiral arms is actually moving outward- like water from a rotating sprinkler. In a galaxy, nothing is moving outward- that's an illusion like we see with a pinwheel.

Ann wrote:Still, LL Pegasi is outstanding in its regularity.

M. Morris et al. wrote:Figure 2. Keck adaptive optics images of AFGL 3068 in 3 near-IR filters. Two sources are apparent, the slightly diffuse one to the west probably being the highly obscured, mass-losing star, and the one to the east being a much less obscured companion at a projected distance of 109 AU at 1 kpc. The first Airy ring in the point spread function for these images has a trefoil pattern which is most evident in the H image of the eastern source. (The ”PAH” filter was used to provide a narrow-band sampling of the 3.3 m continuum, since the usual wideband filters saturated on this strong source.)

DavidLeodis wrote:Is the extremely bright object with the colourful diffraction spikes there by chance alignment and has nothing to do with the spiral?

Ann wrote:

DavidLeodis wrote:Is the extremely bright object with the colourful diffraction spikes there by chance alignment and has nothing to do with the spiral?

My software, Guide, has found a 12th magnitude orange star right next to LL Pegasi,3UC215-331878. Perhaps that is the star that looks so overwhelmingly bright in yesterday's APOD. Whether this star has anything at all to do with LL Pegasi is anyone's guess, or at least I am absolutely stumped.

Remember that the APOD is apparently an infrared image. An orange star would look brighter in infrared than in visual light.

DavidLeodis wrote:Is the extremely bright object with the colourful refraction spikes there by chance alignment and has nothing to do with the spiral?

Ann wrote:
Still, LL Pegasi is outstanding in its regularity.

Chris Peterson wrote:
It is outstanding because of its rarity, but it's the rarity itself I find remarkable. It seems like such structures should be common. All you need is a uniformly rotating body (the Universe is full of those), the uniform ejection of gas (also common), and something to introduce asymmetry (such as a double star system... again, very common). Why don't we see more nebulas like this given how common the individual requirements are?

edhume wrote:
Did anyone see Hale Bopp? The spiral structure of IRAS 23166+1655 reminds me of what I saw in 1997 when we hiked through the snow to our observatory to see Comet Hale Bopp in our club’s 16-inch Cave Newtonian. The spiral structure we saw that night blew me away. It even impressed my seven-year-old daughter. The spiral structure of IRAS 23166+1655 caused that 20-year-old memory to come shooting up. The only thing is, because of the asymmetry of insolation we saw only fragments of the spiral. It was unique, though. A treasured memory!

http://www.racingshadow.com/CometMet/Hale-Bopp/Hale-Bopp.html wrote:

[b][color=#0000FF]Close up of Hale-Bopp nucleus, end Mar 1997[/color][/b]

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Comet C/1995 Hale-Bopp Archive
Observations in April 1997 (Julian Taylor, Oxted)

Note the jets of material being ejected by the nucleus being swept into a spiral as the nucleus rotates anticlockwise. The arrow top right indicates the direction of the Sun. The actual nucleus is lost in the bright cloud of gas and dust at the centre.