APOD: The Orion Bullets (2019 Mar 03)

[APOD Robot]

The Orion Bullets

Explanation: Why are bullets of gas shooting out of the Orion Nebula? Nobody is yet sure. First discovered in 1983, each bullet is actually about the size of our Solar System, and moving at about 400 km/sec from a central source dubbed IRc2. The age of the bullets, which can be found from their speed and distance from IRc2, is very young -- typically less than 1,000 years. As the bullets expand out the top of the Kleinmann-Low section of the Orion Nebula, a small percentage of iron gas causes the tip of each bullet to glow blue, while each bullet leaves a tubular pillar that glows by the light of heated hydrogen gas. The detailed image was created using the 8.1 meter Gemini South telescope in Chile with an adaptive optics system (GeMS). GeMS uses five laser generated guide stars to help compensate for the blurring effects of planet Earth's atmosphere.

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[geckzilla]

I'm still amazed by this nebula within a nebula... just sitting right there in the Orion Nebula for anyone to see, and it's pretty big, too, but it's hidden by all the other glowy gas bits. There was an article I saw about this recently showing a fuller picture of the "bullets" nebula: https://public.nrao.edu/news/2019-alma-salt-star/

[Ann]

I, too, am fascinated by this nebula. Not least because it proves that high-mass star formation is still going on in the Orion Nebula.

There aren't many well-known nebulas that show very clear signs of ongoing massive star formation. Maybe the Lagoon Nebula. But the star inside the central Hourglass nebula inside the Lagoon appears to be older than the star inside the Kleinmann-Low nebula (at least to me, a complete amateur), and the Hourglass nebula itself appears to be a lot more worn by the energetic wind of the central star than the Kleinmann-Low nebula is. At the very least, the Hourglass nebula has "cracked open".

As for familiar nebulas with ongoing massive star formation, M17, the Omega Nebula, is most definitely one such nebula. But then, the entire Omega Nebula seems to be "un-hatched", still wrapped inside its nebular cocoon and guarding all its secrets, unlike the Orion Nebula.

In other words, the Kleinmann-Low nebula is a truly fascinating and very unusual object.

Ann

[wildespace]

One article explains:

"At the center of the giant butterfly-like feature is IRc2, a star 30 times more massive than the sun which is in the process of forming. A strong wind with a speed of more than 100 kilometers per second is blowing out from IRc2, evacuating the butterfly-like cavity and allowing infrared light to escape. Many finger-like features are seen radially emanating from the Orion KL region, produced when the strong stellar wind from IRc2 collides with the surrounding cold material, heating it to around 2000 K and causing the hydrogen molecules to emit light."

http://migall.fastmail.fm.user.fm/astro ... subaru.htm

[Astronymus]

One article explains:

"At the center of the giant butterfly-like feature is IRc2, a star 30 times more massive than the sun which is in the process of forming. A strong wind with a speed of more than 100 kilometers per second is blowing out from IRc2, evacuating the butterfly-like cavity and allowing infrared light to escape. Many finger-like features are seen radially emanating from the Orion KL region, produced when the strong stellar wind from IRc2 collides with the surrounding cold material, heating it to around 2000 K and causing the hydrogen molecules to emit light."

http://migall.fastmail.fm.user.fm/astro ... subaru.htm

I guess the question is more like why these bullets are made of iron gas.

[Ann]

One article explains:

"At the center of the giant butterfly-like feature is IRc2, a star 30 times more massive than the sun which is in the process of forming. A strong wind with a speed of more than 100 kilometers per second is blowing out from IRc2, evacuating the butterfly-like cavity and allowing infrared light to escape. Many finger-like features are seen radially emanating from the Orion KL region, produced when the strong stellar wind from IRc2 collides with the surrounding cold material, heating it to around 2000 K and causing the hydrogen molecules to emit light."

http://migall.fastmail.fm.user.fm/astro ... subaru.htm

I guess the question is more like why these bullets are made of iron gas.

[amateur musing] Globular clusters are usually classified according to their iron content. They are all poor in iron, but those that have the lowest iron contest are classified as the oldest.

Perhaps the iron is simply a by-product of star formation itself. Of course, that doesn't explain why the iron in this APOD would be found at the tip of the "bullets". [/amateur musing]

Ann

[orin stepanek]

Amazing formation! To me they really do look like bullets being shot through water. Do these bullets slow down as they burrow through space?

[neufer]

I guess the question is more like why these bullets are made of iron gas.

[amateur musing] Globular clusters are usually classified according to their iron content. They are all poor in iron, but those that have the lowest iron contest are classified as the oldest.

Perhaps the iron is simply a by-product of star formation itself. Of course, that doesn't explain why the iron in this APOD would be found at the tip of the "bullets". [/amateur musing]

---

<<Type Ia supernovae follow a characteristic light curve—the graph of luminosity as a function of time—after the event. This luminosity is generated by the radioactive decay of nickel-56 through cobalt-56 to iron-56. Type Ia supernovae derive their energy from a runaway nuclear fusion of a carbon-oxygen white dwarf. The details of the energetics are still not fully understood, but the end result is the ejection of the entire mass of the original star at high kinetic energy. Around half a solar mass of that mass is ⁵⁶Ni generated from silicon burning. ⁵⁶Ni is radioactive and decays into ⁵⁶Co by beta plus decay (with a half life of six days) and gamma rays. ⁵⁶Co itself decays by the beta plus (positron) path with a half life of 77 days into stable ⁵⁶Fe.>>

Click to play embedded YouTube video.

<<irony (n.) "figure of speech in which the intended meaning is the opposite of the literal meaning" (usually covert sarcasm under a serious or friendly pretense), c. 1500, from Latin ironia, from Greek eironeia "dissimulation, assumed ignorance," from eiron "dissembler," perhaps related to eirein "to speak." Used in Greek of affected ignorance, especially that of Socrates, as a method of exposing an antagonist's ignorance by pretending to modestly seek information or instruction from him. Thus sometimes in English in the sense "simulated ignorance." Figurative use for "condition opposite to what might be expected; contradictory circumstances; apparent mockery of natural or expected consequences" is from 1640s, sometimes distinguished as irony of fate or irony of circumstances.>>

[Fred the Cat]

Indeed, it is ironic star birth involves iron. How much mass would have to accumulate for birth to lead to an immediate death – similar to a slow supernova?

One thing is for sure - I like the detail of these new optical processes!

[JohnD]

Bullets?
"a small percentage of IRON gas causes the tip of each bullet to glow blue" so cannonballs, surely?

"The Orion Broadside"?

John

[BDanielMayfield]

Bullets?
"a small percentage of IRON gas causes the tip of each bullet to glow blue" so cannonballs, surely?

"The Orion Broadside"?

John

Iron is the 6th most abundant element in the universe. It massively throws its weight around, as today's APOD shows.

[Astronymus]

Iron is the 6th most abundant element in the universe. It massively throws its weight around, as today's APOD shows.

8 out of 10 blood cells liked that post.

[BDanielMayfield]

Iron is the 6th most abundant element in the universe. It massively throws its weight around, as today's APOD shows.

8 out of 10 blood cells liked that post.

Only 8 out of 10?

Iron is a chemical element with symbol Fe (from Latin: ferrum) and atomic number 26. It is a metal in the first transition series. It is by mass the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust. Its abundance in rocky planets like Earth is due to its abundant production by fusion in high-mass stars, where it is the last element to be produced with release of energy before the violent collapse of a supernova, which scatters the iron into space.

....

Iron is required for life.[8][142][143] The iron–sulfur clusters are pervasive and include nitrogenase, the enzymes responsible for biological nitrogen fixation. Iron-containing proteins participate in transport, storage and used of oxygen.[8] Iron proteins are involved in electron transfer.[144]

Structure of Heme b; in the protein additional ligand(s) would be attached to Fe.
Examples of iron-containing proteins in higher organisms include hemoglobin, cytochrome (see high-valent iron), and catalase.[8][145] The average adult human contains about 0.005% body weight of iron, or about four grams, of which three quarters is in hemoglobin – a level that remains constant despite only about one milligram of iron being absorbed each day,[144] because the human body recycles its hemoglobin for the iron content.[146]

[Astronymus]

Only 8 out of 10?

Hemocyanins (also spelled haemocyanins and abbreviated Hc) are proteins that transport oxygen throughout the bodies of some invertebrate animals. These metalloproteins contain two copper atoms that reversibly bind a single oxygen molecule (O2). They are second only to hemoglobin in frequency of use as an oxygen transport molecule. Unlike the hemoglobin in red blood cells found in vertebrates, hemocyanins are not bound to blood cells but are instead suspended directly in the hemolymph. Oxygenation causes a color change between the colorless Cu(I) deoxygenated form and the blue Cu(II) oxygenated form.[1]

https://en.wikipedia.org/wiki/Hemocyanin