Starship Asterisk*

by **Ann** » Thu Dec 04, 2014 12:13 am

Yes, thanks for the helpful illustrations, Geck.

One of the whiskers, the one on the left, appears to be associated with an elongated structure looking like a jet, ending at about 11 o'clock. There might be an elongated structure on the right as well, ending in a bright "cloud" of turbulence.

Ann

by **DavidLeodis** » Thu Dec 04, 2014 12:10 am

Thanks for the help and link geckzilla.

I was amused by the 'curly hair' in the "HTS and Gemini instruments have two different point-spread functions and then, after the processing deconvolution methods have been applied to the relative images, the two systems give us an imaging of the central whiskers with different features, long and straight in the HST imaging, as curly hair in the case of the Gemini imaging".

by **geckzilla** » Wed Dec 03, 2014 9:25 pm

DavidLeodis wrote:I do wonder though where the "streaming whiskers" are in the image, as the explanation in mentioning them would seem to imply that they are obvious features.

I'll outline what I think are the whiskers based on the descriptions this paper. Within, it is mentioned that it is easy to conflate the point spread function with the whiskers, so it seems that the structures which line up the best with the diffraction spikes are the most likely candidates. The linear structure of the whiskers is not as apparent in the gif animation as in other versions of the Homunculus which may be processed to enhance them.

: Whiskers outlined in blue.

by **DavidLeodis** » Wed Dec 03, 2014 6:39 pm

geckzilla wrote:
star struk wrote:Eta Carina picture shows lines arranged in a hexagon pattern from star. Are these the 'whiskers' refered to in picture description?
The six lines which change orientation in one of the three frames of the animation are artifacts. They include the usual x-shaped diffraction pattern created by the struts holding up Hubble's secondary mirror and then one line bisecting them which is a charge bleed caused by electrons overflowing in the detector itself due to the extreme brightness of the star.
EtaCarinae_Hubble_artifacts.jpg
BTW, here is the animation on a forever loop that won't stop after only 5 plays.
http://www.geckzilla.com/astro/CarinaEx ... orever.gif

Thanks geckzilla for that explanation

, as it confirms what I had thought that the whiskers would not be the spikes.

I do wonder though where the "streaming whiskers" are in the image, as the explanation in mentioning them would seem to imply that they are obvious features.

by **Chris Peterson** » Wed Dec 03, 2014 6:08 pm

DoppelBungle wrote:
Chris Peterson wrote:
montylc2001 wrote:What is Eta Carinae's proper motion in relation to Sol? If it is moving away at a relatively high speed from us then in a few million years when it goes supernova it may be on the other side of the galaxy and not visible to Earth.
Radially, it is moving towards us at 25 km/s.
Lucky for us it'll be 95 million years before it gets here :wink:

At least. There's a tangential component, too, which I don't know the value of. But it's possible that in 95 million years it will be farther away from us than it is now.

by **DoppelBungle** » Wed Dec 03, 2014 5:33 pm

Chris Peterson wrote:
montylc2001 wrote:What is Eta Carinae's proper motion in relation to Sol? If it is moving away at a relatively high speed from us then in a few million years when it goes supernova it may be on the other side of the galaxy and not visible to Earth.
Radially, it is moving towards us at 25 km/s.

Lucky for us it'll be 95 million years before it gets here

by **Chris Peterson** » Wed Dec 03, 2014 2:05 am

montylc2001 wrote:What is Eta Carinae's proper motion in relation to Sol? If it is moving away at a relatively high speed from us then in a few million years when it goes supernova it may be on the other side of the galaxy and not visible to Earth.

Radially, it is moving towards us at 25 km/s.

by **montylc2001** » Wed Dec 03, 2014 1:50 am

What is Eta Carinae's proper motion in relation to Sol? If it is moving away at a relatively high speed from us then in a few million years when it goes supernova it may be on the other side of the galaxy and not visible to Earth.

by **Ann** » Wed Dec 03, 2014 12:11 am

Chris wrote:
Yes, and the Homunculus nebula itself is primarily a reflection nebula. But it's embedded in the Eta Carina nebula, which is primarily an emission nebula (with regions of reflection).

The main component of the binary (or perhaps multiple) star Eta Carina is much too cool to ionize an emission nebula. The second component may be hot enough to do the trick.

Of course, the colliding winds of this nebula might certainly cause any hydrogen in the vicinity to glow red.

Ann

by **hoohaw** » Wed Dec 03, 2014 12:09 am

Chris Peterson wrote:
hoohaw wrote:You may remember my question of a few days ago, wondering why we humans find almost all astronomical photos BEAUTIFUL; why, why, from an evolutionary point of view?
The question made no sense to me. Why should it matter from an evolutionary point of view? Our visual aesthetics are based on aspects of color and form, which are universal. We did not evolve the concept of beauty around just those things that were present in our environment.

http://en.wikipedia.org/wiki/Beauty is interesting to read. Is beauty a universal? We, and the flying insects, agree on the "beauty" of the flowers. Is there a mathematics of beauty? Symmetry? But where is symmetry in photos of the interstellar medium?

by **geckzilla** » Tue Dec 02, 2014 10:03 pm

It's beautiful because it's far away, colorful, hard enough to understand that it is practically magical, and not crossing anyone's perceived borders. If nebulas had a habit of making little webs in the corners of houses or had little biting fangs, they'd be as maligned as spiders, which are often every bit as beautiful if not even more so.

by **Chris Peterson** » Tue Dec 02, 2014 9:54 pm

hoohaw wrote:You may remember my question of a few days ago, wondering why we humans find almost all astronomical photos BEAUTIFUL; why, why, from an evolutionary point of view?

The question made no sense to me. Why should it matter from an evolutionary point of view? Our visual aesthetics are based on aspects of color and form, which are universal. We did not evolve the concept of beauty around just those things that were present in our environment.

by **hoohaw** » Tue Dec 02, 2014 9:38 pm

You may remember my question of a few days ago, wondering why we humans find almost all astronomical photos BEAUTIFUL; why, why, from an evolutionary point of view? I said "almost all," and one exception I was thinking of was this very Eta Carinae nebula, which looks like something out of a Medical Pathology Illustrated volume. It looks disgusting! (Again, why? why? and what is beauty?)

by **Boomer12k** » Tue Dec 02, 2014 9:15 pm

Ought to make a nice remnant....hope somebody is around to study it....
Maybe Cats will be the dominant intelligent species then....Planet of the Cats...

:---[===] *

by **ChrisNW** » Tue Dec 02, 2014 8:41 pm

Cool, it could be more!

By far this is my fav star from APOD.

by **Chris Peterson** » Tue Dec 02, 2014 8:35 pm

ChrisNW wrote:Is Eta Carinae a binary system?

At the least.

by **ChrisNW** » Tue Dec 02, 2014 8:29 pm

Is Eta Carinae a binary system?

http://www.nasa.gov/home/hqnews/2005/no ... _star.html

by **Chris Peterson** » Tue Dec 02, 2014 8:17 pm

starsurfer wrote:Doesn't the Homunculus Nebula also have outer parts that are only visible in xray?

Yes, there is a much larger region of very hot ejecta that radiates in soft x-rays but is too tenuous to produce significant signal in the visible spectrum (as well as central structure visible in hard x-rays).

Also isn't the central illuminating star Eta Carinae?

Yes, and the Homunculus nebula itself is primarily a reflection nebula. But it's embedded in the Eta Carina nebula, which is primarily an emission nebula (with regions of reflection).

by **LocalColor** » Tue Dec 02, 2014 7:59 pm

The more data we gather the more we learn. I like the 3 photo "video" very much. Thanks again APOD.

by **starsurfer** » Tue Dec 02, 2014 6:39 pm

Doesn't the Homunculus Nebula also have outer parts that are only visible in xray?

Also isn't the central illuminating star Eta Carinae?

by **Ann** » Tue Dec 02, 2014 5:01 pm

An interesting possibility is that the 1843 event might have been a supernova impostor. If so, it is just possible that Eta Carina blew off so much of itself during those 19th century outbursts that it will not be as brilliant as we might expect it to be when it goes supernova for real.

Ann

by **Chris Peterson** » Tue Dec 02, 2014 4:30 pm

Coil_Smoke wrote:
APOD Robot wrote:its high mass and volatility make it a candidate to explode in a spectacular supernova sometime in the next few million years.
This already seems like a nova event.

Nope. It was neither a nova nor a supernova. (Say that three times quickly.)

by **Coil_Smoke** » Tue Dec 02, 2014 4:08 pm

APOD Robot wrote:its high mass and volatility make it a candidate to explode in a spectacular supernova sometime in the next few million years.

This already seems like a nova event.

by **Ann** » Tue Dec 02, 2014 1:21 pm

Thanks, Geck!

Ann

by **geckzilla** » Tue Dec 02, 2014 1:04 pm

star struk wrote:Eta Carina picture shows lines arranged in a hexagon pattern from star. Are these the 'whiskers' refered to in picture description?

The six lines which change orientation in one of the three frames of the animation are artifacts. They include the usual x-shaped diffraction pattern created by the struts holding up Hubble's secondary mirror and then one line bisecting them which is a charge bleed caused by electrons overflowing in the detector itself due to the extreme brightness of the star.

$Diffraction spikes and charge bleed.$: Diffraction spikes and charge bleed.

BTW, here is the animation on a forever loop that won't stop after only 5 plays.
http://www.geckzilla.com/astro/CarinaEx ... orever.gif

Starship Asterisk*

APOD: Eta Carinae and the Expanding Nebula... (2014 Dec 02)

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