Starship Asterisk*

Thanks for your reply ! :)

[quote="Pezito"]... Anyone ? :?

Since my post, I have digged a little deeper and it would seem that Supernova 1987A is in a constellation visible in the SOUTH hemisphere. Which would indicate that I couldn't have seen it from my country... :oops:[/quote]
Correct. With a declination of -69°, this supernova could only be seen by people south of about +21°. It was certainly not visible from anywhere in France.

... Anyone ? :?

Since my post, I have digged a little deeper and it would seem that Supernova 1987A is in a constellation visible in the SOUTH hemisphere. Which would indicate that I couldn't have seen it from my country... :oops:

Hi everyone,

I'm posting here for the first time (and possibly the last :P ) because this post about Supernova 1987A brings back a memory I've always had - and a question.

I was born in 1977, November 5th and I live in France. When I was a kid, I remember that one night when my mother was driving me to the doctor for a routine injection, I saw a very bright star in the sky. It wasn't a plane or something like that : it didn't move, was MUCH brighter than any other star, and it lasted for several days (or hours ? this I can't remember precisely). I remember that even though I was young and didn't know a lot about space, I wondered at the time if this thing could be a supernova.

Today as I read this article on APOD, I was surprised to know that such a thing happened in 1987 because the dates match ! When Supernova 1987A was discovered I was 9 years old, at the time I was still getting anti-allergic shots every once in a while ; I was also old enough to have a basic knowledge of what a "supernova" was, hence the questioning and the striking memory I kept of this event.

Now my question is : did I see Supernova 1987A, or was it totally unrelated ? Just the date isn't evidence enough but I'm sure you guys can tell me if this event could be seen by the naked eye or not (if it ever was visible in the northern hemisphere, which I have no clue of).

I'm no expert in astronomy but I've always been interested in it, and this very bright and durable "star" I saw as a kid has always been a vivid memory of mine. To find out that I did, in fact, see a supernova back then would be simply amazing ! :)

[float=right][img3="[size=125][color=#0000FF]1908 Summer Olympics in London: British women's gymnastics team[/color][/size]"]http://upload.wikimedia.org/wikipedia/commons/f/f6/London_1908_Gymnastics_women.jpg[/img3][/float][img3="[size=150][color=#0000FF]Rhythmic Gymnastics[/color][/size]"]http://visual.merriam-webster.com/images/sports-games/gymnastics/rhythmic-gymnastics/apparatus.jpg[/img3]

A few years back I constructed a composite image from a whole bunch of Hubble photos and came up with this:

[url=http://Noel.ProDigitalSoftware.com/Astroimages/SN1987A_Combined.jpg][img]http://Noel.ProDigitalSoftware.com/Astroimages/SN1987A_Combined.jpg[/img][/url]

-Noel

[float=right][img]http://i39.tinypic.com/f39stg.png[/img][/float][quote="alphachapmtl"]

Probably unrelated, but it reminds me of
the drop instability, caused by surface tension. :arrow: [/quote]
[size=125]Milk splash constricted by surface tension:

[list]1) Hemispherical splash => conical ring
2) Conical ring => coronal droplets.[/list]

Stellar plasma "splash"
constricted by stellar dipole magnetic field:

[list]1) Spherical "splash" => equatorial disk
2) Equatorial disk => coronal droplets.[/list][/size]

[b][i] http://asterisk.apod.com/viewtopic.php?f=31&t=27501 [/i][/b]

[quote="KarelSculptor"]And why would it not be possible that with this image we enter in part of the universe space where our physical laws are outdated? We always think that physical laws are applicable everywhere in our existing universe , … What if we are wrong??[/quote]
In every way we can examine them (and there are many ways), the laws of physics appear to be the same everywhere. We don't just assume that they are so, but have hard evidence of it.

Certainly, there are plenty of good explanations for these sorts of structures around supernovas that don't require adjusting the laws of physics.

And why would it not be possible that with this image we enter in part of the universe space where our physical laws are outdated? We always think that physical laws are applicable everywhere in our existing universe , … What if we are wrong??

[quote=" http://science.nasa.gov/science-news/science-at-nasa/2008/29may_magnetar/"]
[float=right][img3="[color=#0000FF]A selection of rings and spheres in the Milky Way. From left to right, (1) light echoes from old supernova remnant Cassiopeia A, (2) a blast wave emerging from recent supernova 1987A, and (3) a planetary nebula named The Helix. The ring around SGR 1900+14 is like none of these things.[/color]"]http://science.nasa.gov/media/medialibrary/2008/05/29/29may_magnetar_resources/not_strip.jpg[/img3][img3="[color=#0000FF]This image shows a ghostly ring extending seven light-years across around the corpse of a massive star. The collapsed star, called a magnetar, is located at the exact center of this image. NASA's Spitzer Space Telescope imaged the mysterious ring around magnetar SGR 1900+14 in infrared light.[b] The blue color represents 8-micron infrared light taken by the infrared array camera, [/color][color=#00BF00]green is 16-micron light from the infrared spectograph[/color], and [color=#FF0000]red is 24-micron radiation from the multiband imaging photometer[/color][/b]. [color=#0000FF]The magnetar itself is not visible in this image, as it has not been detected at infrared wavelengths (it has been seen in X-ray light). Magnetars are formed when a massive star ends its life in a supernova explosion, leaving behind a super dense neutron star with an incredibly strong magnetic field. The ring seen by Spitzer could not have formed during the original explosion, as any material as close to the star as the ring would have been disrupted by the supernova shock wave. Scientists suspect that the ring my actually be the edges of a bubble that was hollowed out by an explosive burst from the magnetar in 1998. The very bright region near the center of the image is a cluster of young stars, which may be illuminating the inner edge of the bubble, making it look like a ring in projection.[/color]"]http://www.nasa.gov/images/content/231303main_magnetar-516.jpg[/img3][/float]
[size=150]Strange Ring Found Circling Dead Star[/size]

<<May 29, 2008: NASA's Spitzer Space Telescope has found a bizarre ring of material around the magnetic remains of a star that blasted itself to [url=http://en.wikipedia.org/wiki/Waylon_Smithers]smithereens[/url]. The stellar corpse, called SGR 1900+14, belongs to a class of objects known as magnetars. These are the cores of massive stars that blew up in supernova explosions, but unlike most other dead stars, they have tremendously strong magnetic fields.

The ring was found serendipitously. "I was flipping through archived Spitzer data and that's when I noticed SGR 1900+14 was surrounded by a ring we'd never seen before," says Stefanie Wachter of NASA's Spitzer Science Center at the California Institute of Technology. "The universe is a big place and weird things can happen!" Wachter and her colleagues think that the ring, which is unlike anything ever seen before, formed in 1998 when the [url=http://en.wikipedia.org/wiki/Mr._Burns]crusty iron surface[/url] of the magnetar cracked and erupted in a giant flare. The blast was so powerful, it ionized Earth's upper atmosphere and actually overloaded the instruments of several NASA spacecraft.

Researchers believe the magnetar was surrounded by a cloud of dust and the explosion excavated that cloud, leaving an outer, dusty ring. The ring is oblong, with dimensions of about seven by three light-years. It appears to be flat, or two dimensional, but the data do not rule out the possibility of a more complex 3-dimensional shell. "It's as if the magnetar became a huge flaming torch and obliterated the dust around it, creating a massive cavity," says co-investigator Chryssa Kouveliotou of NASA's Marshall Space Flight Center. Nearby stars lit up the ring so that Spitzer could see it--"a ring of fire marking the magnetar for eternity."
[b][color=#FF0000]
Rings and spheres are common in the universe. For instance, young massive stars use their stellar wind to blow bubbles in space, carving clouds of dust into spherical shapes. Later, when those stars die in supernova explosions, their remains are blasted away, forming beautiful orbs called supernova remnants. Rings can also form around exploded stars whose expanding shells of debris ram into pre-existing dust clouds, causing the dust to glow, as is the case with the supernova remnant 1987A. But the ring around the magnetar SGR 1900+14 fits into none of these categories. For one thing, supernova remnants and the ring around 1987A cry out with X-rays and radio waves. The ring around SGR 1900+14 does not; it only glows at specific infrared wavelengths that Spitzer can see.[/color][/b]

At first, the astronomers thought the ring around SGR 1900+14 must be an infrared echo. These occur when an object sends out a blast wave that travels outward, heating up dust and causing it to glow with infrared light. But when they went back to observe SGR 1900+14 later, the ring didn't move outward as an infrared echo would. A closer analysis revealed that the ring is most likely a carved-out cavity in a dust cloud -- a phenomenon that must be somewhat rare in the universe because it had not been seen before.

The discovery could help scientists figure out if a star's mass influences whether it becomes a magnetar when it dies. Though scientists know that stars above a certain mass will "go supernova," they do not know if mass plays a key role in determining whether the stellar corpse becomes a magnetar or a run-of-the-mill dead star. According to the science team, the glowing ring of dust Spitzer observed connects SGR 1900+14 to a nearby cluster of young stars. By studying the masses of those stars, the scientists might be able to figure out the original mass of SGR 1900+14. "SGR 1900+14 is interacting with its environment, making a big impact on the region where it was born," concludes astronomer and co-investigator Enrico Ramirez-Ruiz of the University of California, Santa Cruz. "This 'dead star' is still alive in many ways.">>[/quote]

Has anyone noticed the radial line appearing to eminate from the center at around 8:00 in the frame dated 2005? Is this a jet? If so what could possibly explain its appearance and disappearance in such a short time? It is surly an artifact. Yes?

Given that the universe is essentially lumpy, with an uneven distribution of matter at every observable level, it makes intuitive sense that different parts of the ring around the star would have greater and lesser densities of previously ejected gas and dust. When the radiation from the supernova hits a denser clump, it would glow more brightly. Am I missing some deeper complication here?

(Those windblown ducklings are awfully cute. I was relieved to see that they were all back on their feet and in formation at the end of clip.)

Nice one, Neufer!
Karel,
Niven is a 'hard' SF writer who avoids anything that has to be explained by magic.
But this is an astronomy site!
I'm happy if someone (Chris?) can say, we don't know.

alpha,
Again, nice analogy, but what would be the equivalent of surface tension?
Gravity, even in a gas compressed by the shock wave seems unlikely, too weak.

But you may not be so far wrong! How about this explanation, "standing accretion shock instability " (SASI),causing vortices where the shock wave interacys with infalling gas
Foglizzo et al offer a water model at http://physics.aps.org/articles/v5/13
John

[quote="KarelSculptor"]I wonder if these are the remnants of an asteroid belt around that star. Our sun has one, probably many stars have such a ring of rest material debris.[/quote]
It seems unlikely, given that the density of the (or probably any) asteroid belt is so incredibly low. The total mass of all the material in the asteroid belt is less than a small moon- insignificant compared to the mass ejected by the exploding star.

I wonder if these are the remnants of an asteroid belt around that star. Our sun has one, probably many stars have such a ring of rest material debris.
Larry Niven the writer of the book "RingWorld" should see this,.. So he can find the 3 feeted Puppeteers over there.

[quote="JohnD"]Is there any explanation for the "ring of pearls" effect, discrete hot centres within the ring at regular intervals?
[/quote]
Probably unrelated, but it reminds me of the drop instability, caused by surface tension.
Of course duckling instability is always a possibility.

[img]http://i39.tinypic.com/f39stg.png[/img]

[img]http://i42.tinypic.com/vymvr4.jpg[/img]

Viscous fingering, or the Saffman-Taylor instability:
[img]http://i40.tinypic.com/nnkx07.jpg[/img]

The growing nebula in the center reminds me more of the Eta Carinae nebula than anyting else. Maybe this two-lobed structure will evolve into a more "normal" looking supernova remnant, but I still find the similarity to be striking.

Neufer!! [img]http://i279.photobucket.com/albums/kk157/dyedinthewool/Smilies/rollin.gif[/img]

[quote="JohnD"]

Is there any explanation for the "ring of pearls" effect, discrete hot centres within the ring at regular intervals?[/quote]
It is a consequence of the magnetohydrodynamical [url=http://www.youtube.com/watch?v=SEBLt6Kd9EY]duckling instability[/url].

[quote="biddie67"]

Is there any speculation about why the ring wasn't pushed outward by the moving blast?[/quote]
Only the most tenuous part of the blast has hit a much denser ring thus far
causing it to expand at a much slower rate than 60 million km/hr.

Is there any explanation for the "ring of pearls" effect, discrete hot centres within the ring at regular intervals?

John

[i]Zoooooooooooom![/i]

[quote="owlice"][quote="Bear"]How is a 60 million km/h collision possible when light travels 300,000 km/h?[/quote]
Light travels at 300,000 km/second, not per hour.[/quote]

Which turns out to be over 1 billion km/hour. :) Possible!

:shock: I didn't know a collision was involved in this supernova! :?