APOD: Star Factory Messier 17 (2013 Apr 18)

[APOD Robot]

Star Factory Messier 17

Explanation: Sculpted by stellar winds and radiation, the star factory known as Messier 17 lies some 5,500 light-years away in the nebula-rich constellation Sagittarius. At that distance, this degree wide field of view spans almost 100 light-years. The sharp, composite, color image utilizing data from space and ground based telescopes, follows faint details of the region's gas and dust clouds against a backdrop of central Milky Way stars. Stellar winds and energetic light from hot, massive stars formed from M17's stock of cosmic gas and dust have slowly carved away at the remaining interstellar material producing the cavernous appearance and undulating shapes. M17 is also known as the Omega Nebula or the Swan Nebula.

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[ta152h0]

when a star decides to go KABOOM !does it do this in miriads of smaller kabooms all at once, possibly explainig all the filaments and other various shapes we see in this image and like the Tarantula nebula ? Called " pinging " when it happens in my FORD .

[Beyond]

when a star decides to go KABOOM !does it do this in miriads of smaller kabooms all at once, possibly explainig all the filaments and other various shapes we see in this image and like the Tarantula nebula ? Called " pinging " when it happens in my FORD .

Gas not being detonated correctly in your Ford, isn't the same thing as a star going Ka-Boom, but if the ping is bad enough, it could burn a hole through your piston, just like an exploding star blasts a hole through whatever is around it. So you don't want to hear stars at work, in your Ford.

[Ann]

This is a great image of a most fascinating object. I want to say special thanks to Rob Gendler, whose processing skills are wonderful to see.

Ann

[MargaritaMc]

when a star decides to go KABOOM !does it do this in miriads of smaller kabooms all at once, possibly explainig all the filaments and other various shapes we see in this image and like the Tarantula nebula ? Called " pinging " when it happens in my FORD .

I think that the answer is probably KABOOM! all at once.

The nebula contains a large amount of dark obscuring material, which is obvious in its remarkable features. This matter has been heated by the hidden young stars, and shines brightly in infrared light.http://messier.seds.org/m/m017.html

The dark dust filaments that lace the center of Omega Nebula were created in the atmospheres of cool giant stars and in the debris from supernova explosions. http://apod.nasa.gov/apod/ap040208.html

Core-collapse Supernovas

The general picture for Type II, Type Ib and Type Ic supernovas - also called core-collapse supernovas - goes something like this. When the nuclear power source at the center or core of a star is exhausted, the core collapses. In less than a second, a neutron star (or a black hole, if the star is extremely massive) is formed. The formation of a neutron star releases an enormous amount of energy in the form of neutrinos and heat, which reverses the implosion. All but the central neutron star is blown away at speeds in excess of 50 million kilometers per hour as a thermonuclear shock wave races through the now expanding stellar debris, fusing lighter elements into heavier ones and producing a brilliant visual outburst that can be as intense as the light of several billion Suns.

Thermonuclear Supernovas
Type Ia supernovas, in contrast, are observed in all kinds of galaxies, and are produced by white dwarf stars, the condensed remnant of what used to be sun-like stars. A white dwarf star, a dense ball primarily composed of carbon and oxygen atoms, is intrinsically the most stable of stars, as long as its mass remains below the so-called Chandrasekhar limit of 1.4 solar masses.
If, however, accretion of matter from a companion star or the merger with another white dwarf, push a white dwarf star over the Chandrasekhar limit of 1.4 solar masses, the temperature in the core of the white dwarf will rise, triggering explosive nuclear fusion reactions that release an enormous amount of energy. The star explodes in about ten seconds, leaving no remnant. The expanding cloud of ejecta glows brightly for many weeks as radioactive nickel produced in the explosion decays into cobalt and then iron.http://chandra.harvard.edu/xray_sources/supernovas.html

But the quote from the February 2004 Apod above does say 'supernova explosions - so, it's KABOOM! , but repeated several times in this nebula

Margarita
PS. But this might complicate the picture? I'm too new to this subject to know.
http://asterisk.apod.com/viewtopic.php? ... 98#p197424.

[neufer]

Click to play embedded YouTube video.

Click to play embedded YouTube video.

[Boomer12k]

when a star decides to go KABOOM !does it do this in miriads of smaller kabooms all at once, possibly explainig all the filaments and other various shapes we see in this image and like the Tarantula nebula ? Called " pinging " when it happens in my FORD .

The shapes and filaments in this image are from Stellar Winds, Not Supernova. It is not like the Crab nebula, where 1 star blew up. But a star forming region. The pressure from the radiation is so fast and powerful from young stars they eat away at the surrounding dust, blowing it away, ionizing the gases, and making them glow...as it dissipates, the cavernous shapes are created. So, this is not really due to stars blowing up. Your Ford not withstanding...

From Wikipedia...
"An open cluster of 35 stars lies embedded in the nebulosity and causes the gases of the nebula to shine due to radiation from these hot, young stars; however the actual number of stars in the nebula is much higher - up to 800, 100 of spectral type earlier than B9, and 9 of spectral type O,[3] plus >1000 stars in formation on its outer regions.[5] It's also one of the youngest clusters known, with an age of just 1 million years.[7]

The luminous blue variable HD 168607, located in the south-east part of the Omega nebula, is generally assumed to be associated with it; its close neighbor, the blue hypergiant HD 168625, may be too."

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[Boomer12k]

Awesome looking image...much more detailed than mine, of cource. I hope to do better when the weather gets nicer...

Mine is a closer up view... My image is of the TOP CENTER MOST PART OF THE APOD PICTURE. The part that looks like a Pterodactyl looking Head...just framed above the blue stars, with the neck going down between the two sets of blue stars to the left of the head.
Always wonderful and inspiring to see the bigger area and all the details.

:---[===] *

[K1NS]

Forgive my pedantry, which obscures the point of this beautiful image, but instead of saying "against a backdrop of central Milky Way stars," I believe the caption should read "behind a foreground of central Milky Way stars."

[Chris Peterson]

Forgive my pedantry, which obscures the point of this beautiful image, but instead of saying "against a backdrop of central Milky Way stars," I believe the caption should read "behind a foreground of central Milky Way stars."

Or perhaps, "embedded in a sea of central Milky Way stars", as we see stars both in front of and behind the nebula.

[neufer]

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Forgive my pedantry, which obscures the point of this beautiful image, but instead of saying "against a backdrop of central Milky Way stars," I believe the caption should read "behind a foreground of central Milky Way stars."

Or perhaps, "embedded in a sea of central Milky Way stars", as we see stars both in front of and behind the nebula.

[NoelC]

What a beautiful nebula when shown in all its full extent. Wow.

I have a question though... What's making it greenish, just above center? Green is so uncommon in astronomy, that this really jumps out at me.

And with all due respect to Mr. Gendler, I believe he may have de-emphasized the stars a bit too much in this, digging dark holes in the sky around them and making them anything but white. Never forget that stars are beautiful too, just as they are! In this particular image, since the bright ones are mostly out at the extremities, allowing them to be brilliant doesn't take detract from the nebula at all.

-Noel

[Boomer12k]

What a beautiful nebula when shown in all its full extent. Wow.

I have a question though... What's making it greenish, just above center? Green is so uncommon in astronomy, that this really jumps out at me.

And with all due respect to Mr. Gendler, I believe he may have de-emphasized the stars a bit too much in this, digging dark holes in the sky around them and making them anything but white. Never forget that stars are beautiful too, just as they are! In this particular image, since the bright ones are mostly out at the extremities, allowing them to be brilliant doesn't take detract from the nebula at all.

-Noel

Noel...I am thinking there are some explanations. There are Blue Stars...there are Yellow Stars...there is dust reflecting/refracting both...and yellow and blue make green.
The other thought was, since it is a Space and Land Composite image...it could be the combining of the images and data used. In other words it could be an OVERLAY artifact...there is some YELLOWING on the lower right area too..and if there were more blue from blue stars...it might appear greener too...
It could also be from FILTERS used...

I am no expert though...

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[MargaritaMc]

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Forgive my pedantry, which obscures the point of this beautiful image, but instead of saying "against a backdrop of central Milky Way stars," I believe the caption should read "behind a foreground of central Milky Way stars."

Or perhaps, "embedded in a sea of central Milky Way stars", as we see stars both in front of and behind the nebula.

Great_Atuin_plus_elephants_and_Discworld.jpeg

Great A'Tuin

Great A'Tuin is the Giant Star Turtle (of the fictional species: Chelys galactica) who travels through the Discworld universe's space, carrying four giant elephants (named Berilia, Tubul, Great T'Phon, and Jerakeen) who in turn carry the Discworld. The narration has described A'Tuin as "the only turtle ever to feature on the Hertzsprung-Russell diagram."

Great A'Tuin's gender is unknown (though in The Colour of Magic Pratchett describes the turtle as male), but the subject of much speculation by some of the Disc's finest scientific minds. The sex of the World Turtle is pivotal in proving or disproving a number of conflicting theories about the destination of Great A'Tuin's journey through the cosmos. If, as the Discworld version of the popular "big bang theory" states, Great A'Tuin is moving from the Birthplace to the Time of Mating, then at the point of mating the civilizations of the Disc might be crushed, simple slide off, or else the entire world will end. The hypothesis is that all stars in the sky are obviously also worlds carried by giant turtles, and that when all the turtles meet they will mate passionately, for the first and only time; from that mating, it is hypothesized that new turtles would be born to carry a new pattern of worlds. Attempts by telepaths to learn more about Great A'Tuin's intents have not met with much success, mainly because they did not realise that its brain functions are on such a slow timescale. All they've been able to discern is that the Great A'Tuin is looking forward to something.http://en.m.wikipedia.org/wiki/Discworld_(world)

[neufer]

I have a question though... What's making it greenish, just above center?
Green is so uncommon in astronomy, that this really jumps out at me.

The usual suspect: OIII : http://www.astrodave.com/images/m17-hao ... 62706.html

[Case]

Forgive my pedantry, which obscures the point of this beautiful image, but instead of saying "against a backdrop of central Milky Way stars," I believe the caption should read "behind a foreground of central Milky Way stars."

I think the original caption is quite accurate when looking “from above” at the situation. The stars in the center of the Milky Way, even a whole arm, are behind M17 from our point of view.

[neufer]

Forgive my pedantry, which obscures the point of this beautiful image, but instead of saying "against a backdrop of central Milky Way stars," I believe the caption should read "behind a foreground of central Milky Way stars."

I think the original caption is quite accurate when looking “from above” at the situation. The stars in the center of the Milky Way, even a whole arm, are behind M17 from our point of view.

The bright (i.e., HD 168701: Mag. 7.7) star in the lower left has a distance of ~3300 light years (vs. ~5500 for M17).

However, most of the other stars are probably further than that since they don't have designated distances.

[RobGendler]

Noel, I didn't deemphasize any stars. The luminance was from a narrowband h-alpha data set which has created a mismatch of star sizes between luminance and chominance. This explains some of the dark halos around bright stars. The colors are otherwise accurate. The color data was taken Under very dark skies in namibia by Wolfgang Promper. Composites like these from multiple different data sources are very challenging to make and there are always some flaws.

[NoelC]

Thank you for the explanation, Rob.

I hope you will grow to understand that my comment/criticism was meant constructively. And I do realize the difficulties in assembling images from widely varying data sources. I'm sorry I misinterpreted your difficulties in assembly as an attempt to de-emphasize the stars. You made it look so good (as always) that it's hard to know what level of raw data went into it.

-Noel