Starship Asterisk*

Chris Peterson wrote: ↑Sun May 30, 2021 9:14 pm How come this ring is no circle?
See the reference I provided earlier that argues for the shape being a combination of a spherical shell and a bipolar shell.

VictorBorun wrote: ↑Sun May 30, 2021 11:18 am

Click to view full size image

How come this ring is no circle?
There must have been some strange things in the star's equator at the time this ring was teared off.
Like a dwarf companion. Or a rogue dwarf that roamed into AG Car.

VictorBorun wrote: ↑Sun May 30, 2021 11:18 am
How come this ring is no circle?

There must have been some strange things in the star's equator at the time this ring was teared off.
Like a dwarf companion. Or a rogue dwarf that roamed into AG Car.

• There is no clear explanation of how the central star could produce the nebula's shape :

https://en.wikipedia.org/wiki/Red_Square_Nebula wrote:

Images de la NASA de la nébuleuse du Carré rouge

---

<<The Red Square Nebula is a celestial object located in the area of the sky occupied by star MWC 922 in the constellation Serpens. The first images of this bipolar nebula, taken using the Mt. Palomar Hale telescope in California, were released in April 2007. It is notable for its square shape, which according to Sydney University astrophysicist Peter Tuthill, makes it one of the most nearly discrete-symmetrical celestial objects ever imaged.

The explanation proposed by Tuthill and his collaborator James Lloyd of Cornell University is that the square shape arises from two cone shapes placed tip-to-tip, as seen from the side. This also explains the "double-ring" structure seen in SN 1987A.

A series of faint spokes radiate from the center of the structure. One possible explanation is that these spokes are shadows cast by periodic ripples or waves on the surface of an inner disk close to the central star.

• There is no clear explanation of how the central star could produce the nebula's shape:
  
  Towards the end of their lives, many low-mass stars, like the Sun, slough off their outer layers to produce striking 'planetary' nebulae. But the hot star at the heart of the Red Square nebula, called MWC 922, appears to be relatively massive, suggesting another process formed its signature shape. "How did all this beautiful, crisp structure form?" asks Peter Tuthill of the University of Sydney in Australia. "This is the million dollar question.">>

VictorBorun wrote: ↑Sat May 29, 2021 12:07 pm
I wonder why the distance is not gauged by light waves.

The brightness of the star changes in days or months; the ring of cometary knots is 1-4 ly from the star; we must see the flashes spreading out, must not we?

https://en.wikipedia.org/wiki/RS_Puppis wrote:

Light curve of RS Puppis recorded by NASA's TESS

---

AAVSO light curve of luminous blue variable AG Car from 1940 to 2011.

---

<<RS Puppis (or RS Pup) is a Cepheid variable star around 6,000 ly away in the constellation of Puppis. It is one of the biggest and brightest known Cepheids in the Milky Way galaxy and has one of the longest periods for this class of star at 41.5 days.

The distance to RS Puppis is important because Cepheids serve as a marker for distances within the Milky Way galaxy and for nearby galaxies.

Because it is located in a large nebula, astronomers using the ESO's New Technology Telescope at La Silla Observatory, Chile have been able to measure its distance in 2008 by strictly geometric analysis of light echoes from particles in the nebula, determining it to be 1,992 ± 28 parsecs (6,497 ± 91 ly) from Earth, the most accurate measurement achieved for any Cepheid as of early 2008.

The light echo technique was used again in 2014, this time with Hubble Space Telescope Advanced Camera for Surveys polarimetric images. The distance obtained by these measurements is 1,910 ± 80 parsecs (6,230 ± 260 ly).

In Gaia Data Release 2, a direct geometric parallax of 0.5844±0.0260 mas was derived, corresponding to a distance of 1,710 ± 80 parsecs (5,580 ± 260 ly).>>

RJN wrote: ↑Thu May 27, 2021 12:45 am > "You didn't "reprocess" anything."

Yes, OK. My bad again. I have now removed the prefix "re" from the main NASA text, so that "reprocessing" has become "processing".

- RJN

bystander wrote: ↑Wed May 26, 2021 4:19 am Giant Star on the Edge of Destruction
NASA | GSFC | STScI | HubbleSite | ESA Hubble Photo Release | 2021 Apr 23

RJN wrote: ↑Thu May 27, 2021 12:45 am > "You didn't "reprocess" anything."

Yes, OK. My bad again. I have now removed the prefix "re" from the main NASA text, so that "reprocessing" has become "processing".

- RJN

johnnydeep wrote: ↑Wed May 26, 2021 5:04 pm

orin stepanek wrote: ↑Wed May 26, 2021 11:32 am AgCar_HubbleSchmidt_2212.jpg
Beautiful star; too bad it it going to go Kaput! Or may be it has
already; we are looking at it 20,000 years ago!

Tried to get picture of kitty; but it must not be allowed!

Works for me:

Click to view full size image

m.clayton wrote: ↑Wed May 26, 2021 11:44 pm If the nebula is 20,000 light-years away, but only 10,000 years old, how come we can see it? Wouldn't it take another 10,000 years for the light from the nebula to reach us?

geckzilla wrote: ↑Wed May 26, 2021 10:30 pm

Chris Peterson wrote: ↑Wed May 26, 2021 10:27 pm

geckzilla wrote: ↑Wed May 26, 2021 10:23 pm Someone's going to have to let me know what they mean by "reprocessed" because to me that means I took work that was processed by someone else and then processed over their processing, which I did not do.

Agreed. You were working with the raw images, or base calibrated images, right? So yeah, you processed them to create the final image. You didn't "reprocess" anything.

Right, I was working with the same FITS data produced by the pipeline that Joe worked with when he did his version. I didn't reprocess it anymore than he reprocessed it.

Chris Peterson wrote: ↑Wed May 26, 2021 10:27 pm

geckzilla wrote: ↑Wed May 26, 2021 10:23 pm Someone's going to have to let me know what they mean by "reprocessed" because to me that means I took work that was processed by someone else and then processed over their processing, which I did not do.

Agreed. You were working with the raw images, or base calibrated images, right? So yeah, you processed them to create the final image. You didn't "reprocess" anything.

geckzilla wrote: ↑Wed May 26, 2021 10:23 pm Someone's going to have to let me know what they mean by "reprocessed" because to me that means I took work that was processed by someone else and then processed over their processing, which I did not do.

orin stepanek wrote: ↑Wed May 26, 2021 11:32 am AgCar_HubbleSchmidt_2212.jpg
Beautiful star; too bad it it going to go Kaput! Or may be it has
already; we are looking at it 20,000 years ago!

Tried to get picture of kitty; but it must not be allowed!

The Outburst Clouds of Star AG Car
Image Credit: NASA, ESA, STScI; Processing: Judy Schmidt; Text: Anders Nyholm

NCTom wrote: ↑Wed May 26, 2021 2:32 pm Are we looking through the thin gases facing us of a great ball of expelled material, or is this some kind of doughnut? My first thought is the material was expelled semi-uniformly in all directions.