Starship Asterisk*

Posted: **Wed May 26, 2021 4:05 am**

The Outburst Clouds of Star AG Car

Explanation: What created these unusual clouds? At the center of this 2021 Hubble image sits AG Carinae, a supergiant star located about 20,000 light-years away in the southern constellation Carina. The star's emitted power is over a million times that of the Sun, making AG Carinae one of the most luminous stars in our Milky Way galaxy. AG Carinae and its neighbor Eta Carinae belong to the scarce Luminous Blue Variable (LBV) class of stars, known for their rare but violent eruptions. The nebula that surrounds AG Car is interpreted as a remnant of one or more such outbursts. This nebula measures 5 light-years across, is estimated to contain about 10 solar masses of gas, and to be at least 10,000 years old. This Hubble image, taken to commemorate Hubble's 31st launch anniversary, is the first to capture the whole nebula, offering a new perspective on its structure and dust content. The LBVs represent a late and short stage in the lives of some supergiant stars, but explaining their restlessness remains a challenge to humanity's understanding of how massive stars work.

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Posted: **Wed May 26, 2021 4:19 am**

Posted: **Wed May 26, 2021 5:54 am**

Subhanalloh. Very beautiful. It seems that it happened in a plane perpendicular to our line of view.

Posted: **Wed May 26, 2021 11:32 am**

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!

Posted: **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.

Posted: **Wed May 26, 2021 3:17 pm**

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.

From https://arxiv.org/pdf/1504.03204.pdf,

In the Hα light, the dynamics points to a spherically expanding shell distorted by a more extended bipolar nebula (Smith 1991; Nota et al. 1992). In projection on the sky, the shell appears as an elliptical ring with PA ~131°, different from the infrared shell PA. Nevertheless, the contour image of the optical emission (both bright and faint) superimposed on the infrared image of the nebula at 70μm as illustrated in the right panel of Fig. 2 shows that the overall morphology of the gas nebula is similar to the infrared dust morphology, although the Hα+[NII]ring nebula appears slightly smaller and more elliptical than the infrared nebula. The bright region at the southwestern part of the gas nebula coincides with the bright region of the infrared dust nebula. The northern faint extended structure, which appears both in the infrared and in the optical, is likely a lobe of the bipolar nebula. The extension seen to the south in the Hα+[NII]map and in the velocity maps of Smith (1991) could constitute a part of a second fainter lobe. The system may thus consist of a typical bipolar nebula seen roughly through the poles (i.e., at inclination ~30°), with two faint lobes and a bright waist.

Posted: **Wed May 26, 2021 4:20 pm**

I was going to ignore this APOD, because I've seen this picture too many times before. But then I saw...

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

: Anders Nyholm. Photo: Alexis Brandeker

Anders!! Hi, Anders! Pretty long time no see, but I'll never forget when you used to be a member of our astronomy club, Astronomiska föreningen Tycho Brahe, and give brilliant lectures and speeches there!

Look at Anders' lovely Tycho Brahe shirt!

Ann

Posted: **Wed May 26, 2021 4:55 pm**

Click to play embedded YouTube video.

Posted: **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

Posted: **Wed May 26, 2021 9:39 pm**

At the request of the News Chief of the Space Science Scientific Institute (STScI), I have added the words "reprocessed by Judy Schmidt" to the main NASA text for this APOD. I also want to point out the an STScI team headed by Joseph DePasquale themselves did a very impressive job of processing this image, and their version can be found here: https://hubblesite.org/contents/news-re ... s-2021-017 and is described here: https://illuminateduniverse.org/2021/04 ... d-the-sun/.

- RJN

Posted: **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.

Posted: **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.

Posted: **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.

Posted: **Wed May 26, 2021 10:34 pm**

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.

Sounds like the attribution should be returned to the original form.

Posted: **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?

Posted: **Wed May 26, 2021 11:51 pm**

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?

Because we measure age by time of observation. It doesn't matter how far away it is. Think of it as "we are seeing a nebula that is 10,000 years into its development".

Posted: **Thu May 27, 2021 12:16 am**

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

Thanks; I kept getting the Microsoft edge logo and not the picture; even though I was on Firefox!

Posted: **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

Posted: **Thu May 27, 2021 2:19 am**

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

Well, it's not really your fault if someone from STScI told you that's what it should be. You'd think they'd know what they're talking about.

Posted: **Thu May 27, 2021 11:29 am**

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

Thanks bystander! the view from Hubble without the spikes is very impressive!

Posted: **Fri May 28, 2021 2:21 am**

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

So, we now can note that there was "retexting" by Robert J. Nemiroff.

Anyway, a very fine bit of processing it was, Geck!
The dark red outflow at the top is quite nice. And the cometary knots and other shapes are simply stunning.

Posted: **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?

Posted: **Sat May 29, 2021 2:14 pm**

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?

The brightness of AG Carinae changes irregularly in months or decades.

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).>>

Posted: **Sat May 29, 2021 5:17 pm**

so what's keeping us from dealing with AG Car too?
Or are there doubts as to what in the brightness history was caused by thick dust fluctuations in our line of sight?

Posted: **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.

Starship Asterisk*

APOD: The Outburst Clouds of Star AG Car (2021 May 26)

APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Giant Star on the Edge of Destruction (AG Carinae)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: Giant Star on the Edge of Destruction (AG Carinae)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)

Re: APOD: The Outburst Clouds of Star AG Car (2021 May 26)