APOD: At the Heart of Orion (2012 Oct 06)

APOD Robot · Post by **APOD Robot** » Sat Oct 06, 2012 4:06 am

At the Heart of Orion

Explanation: Near the center of this sharp cosmic portrait, at the heart of the Orion Nebula, are four hot, massive stars known as the Trapezium. Gathered within a region about 1.5 light-years in radius, they dominate the core of the dense Orion Nebula Star Cluster. Ultraviolet ionizing radiation from the Trapezium stars, mostly from the brightest star Theta 1 Orionis C powers the complex star forming region's entire visible glow. About three million years old, the Orion Nebula Cluster was even more compact in its younger years and a recent dynamical study indicates that runaway stellar collisions at an earlier age may have formed a black hole with more than 100 times the mass of the Sun. The presence of a black hole within the cluster could explain the observed high velocities of the Trapezium stars, The Orion Nebula's distance of some 1500 light-years would make it the closest known black hole to planet Earth.

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wolfie138 · Post by **wolfie138** » Sat Oct 06, 2012 7:03 am

Can someone explain to a thickie like me : how was this more compact in the past, if there's a mega black hole there? i thought the gravity from those was supposed to draw everything in, so i'd expect it to be more compact now :-/

cheers!

Ann · Post by **Ann** » Sat Oct 06, 2012 7:17 am

To my knowledge there is no evidence of any sort of black hole in the Orion Nebula.

One of the links in the caption of today's APOD does talk about a possible black hole in the Orion Nebula, yes. The link takes us to an astronomical paper written by Ladislav Subr (Prague), Pavel Kroupa (Bonn) and Holger Baumgardt (Queensland). In the abstract (the summary of the article), the authors wrote:

We speculate that the runaway-mass star may have collapsed directly into a massive black hole (Mbh > 100Msun).

The authors speculate that there might be a black hole in the Orion Nebula, but I have never heard anyone else back up that view. Please note that the black hole would have formed in an unusual way, by a direct collapse with no ensuing explosion. To my knowledge, there exists no hard evidence that a black hole has ever formed that way, certainly not in the present-day universe.

Ann

Ann · Post by **Ann** » Sat Oct 06, 2012 8:29 am

This Hubble image has been processed by Robert Gendler, who is a master at color perfection. We may therefore conclude that the colors in today's APOD are meaningful and close to what the human eye would see, if our eyes had been more sensitive but our color perception unchanged.

Note that all the bright stars are blue. These stars are also intrinsically blue, which means that they are all hotter than the Sun, many of them very much hotter. On the other hand, a few relatively prominent stars in the upper parts of today's APOD are yellowish. Although there might possibly be some connection between some dark dust structures in the nebula and the yellowish stars, suggesting that the yellow stars belong to the nebula, they could also be foreground stars. There are a number of small stars of various colors scattered in parts of the nebula, and the reddest ones are probably strongly reddened by dust. Alternatively, they might be infrared-bright stars that haven't yet reached the main sequence.

Note the yellowish color of the innermost parts of the Orion Nebula, the Trapezium region. The yellow color is caused by a mixture of red Ha emission and blue-green OIII emission. Since this is a basically true-color picture, red emission is caused by Ha emission or, in some cases, SII emission. Clearly blue parts of the nebula are mainly lit by reflection nebulosity. Dark structures are unilluminated dust.

Note the pre-planetary disks around many of the small stars near the bright blue stars in the Trapezium! These disks would be solar systems in the making, if they weren't being blown away by the harsh winds from the hot bright stars in the Trapezium.

Ann

neufer · Post by **neufer** » Sat Oct 06, 2012 9:14 am

: [url=http://arxiv.org/abs/1209.2114]Catch me if you can:[/url][b][color=#FF8000] is there a runaway-mass black hole in the Orion Nebula Cluster?[/color][/b]

Chris Peterson · Post by **Chris Peterson** » Sat Oct 06, 2012 2:12 pm

wolfie138 wrote:Can someone explain to a thickie like me : how was this more compact in the past, if there's a mega black hole there? i thought the gravity from those was supposed to draw everything in, so i'd expect it to be more compact now :-/

Black holes typically draw very little in. That's one of those myths that just won't go away (thank you Disney!). A black hole may suck up material very, very close to it if that material is dense enough to behave as a fluid, and lose energy to collisional processes (even an ordinary star can do this). Dynamically, a black hole is just another gravitational source, and acts like one. Nearby less massive bodies will orbit it. Even a 100 solar mass black hole in the middle of a nebula like this will have small impact over most of the region in comparison to other stars and to the dissipative winds the hottest ones are producing.

Psnarf · Post by **Psnarf** » Sat Oct 06, 2012 3:43 pm

Thank you for providing the large cropped image. There's a lot going on in there!
I wonder what's the deal with the small stars with tails? There's a couple of them below and to the left of the massive star at 6 o-clock. Follow a line from the 9-o-clock star through the small bright star above the 3-o-clock star, there's another. They appear similar to comets. http://messier.seds.org/more/m042_hst3.html suggests that the radiation from the four massive stars is evaporating those pollywogs. Could there have been enough of that going on to form parts of the nebula?

BDanielMayfield · Post by **BDanielMayfield** » Sat Oct 06, 2012 3:50 pm

Hi everyone. Other than my introductory post in the "How did you become interested in astronomy?" thread this is my first real post on apod, but I frequently post on Sky and Telescople's news items. Ann, I've enjoyed and will continue to enjoy your extensive knowelge of this science that we all love, but I think that you have missed some recent news about the possiblity of a black hole in the heart of the Orion Nebula:

http://www.skyandtelescope.com/news/A-B ... 83711.html

This science is advancing so fast, no one can be totally up to date all the time

Bruce

BDanielMayfield · Post by **BDanielMayfield** » Sat Oct 06, 2012 4:12 pm

Sorry Ann, I made the rokie mistake of overreacting to your first statement and then commenting without reading the rest of your comment. So you are fully aware of this news but are very doubtful, as I was also at first. Why do you discount Subr et al's "speculation"? After the questions others and myself had about the absence of visible evidence for the black hole were addressed I became more accepting of this idea.

Bruce

bystander · Post by **bystander** » Sat Oct 06, 2012 5:12 pm

Ann wrote:To my knowledge there is no evidence of any sort of black hole in the Orion Nebula.

One of the links in the caption of today's APOD does talk about a possible black hole in the Orion Nebula, yes. The link takes us to an astronomical paper written by Ladislav Subr (Prague), Pavel Kroupa (Bonn) and Holger Baumgardt (Queensland). In the abstract (the summary of the article), the authors wrote:

We speculate that the runaway-mass star may have collapsed directly into a massive black hole (Mbh > 100Msun).
The authors speculate that there might be a black hole in the Orion Nebula, but I have never heard anyone else back up that view. Please note that the black hole would have formed in an unusual way, by a direct collapse with no ensuing explosion. To my knowledge, there exists no hard evidence that a black hole has ever formed that way, certainly not in the present-day universe.

Ann

Astrophysicists speculate there is a supermassive black hole at the heart of the Milky Way, but no one has ever seen it. With an article published in The Astrophysical Journal, I can only assume the authors' speculation of a black hole in the Orion Nebula is backed up with persuasive evidence. What scientists mean by speculation is very different than the common usage of the term. After all, gravity is only a theory.

Chris Peterson · Post by **Chris Peterson** » Sat Oct 06, 2012 5:25 pm

bystander wrote:Astrophysicists speculate there is a supermassive black hole at the heart of the Milky Way, but no one has ever seen it. With an article published in The Astrophysical Journal, I can only assume the authors' speculation of a black hole in the Orion Nebula is backed up with persuasive evidence. What scientists mean by speculation is very different than the common usage of the term. After all, gravity is only a theory.

Of course, the black hole at the center of the Milky Way has been observed about as conclusively as any black hole can be. Barring all of our gravitational theory being massively wrong (which is unbelievably unlikely) there is no plausible explanation for the observed motions of stars in the galaxy center except for a supermassive black hole.

I suspect that the suggestion in the case of Orion is based on less persuasive evidence, given that the view is not currently widely held. Further observation can be expected to shift understanding in that respect one way or the other.

Our understanding of nature derives from theories, and the strength of theories rests on observational evidence. There are very strong theories, and much weaker ones. Weak ones aren't bad, they simply lack as much observational support as strong ones.

bystander · Post by **bystander** » Sat Oct 06, 2012 5:29 pm

Yes, Chris, I am very aware of that. I guess the sarcasm was lost on you.

Chris Peterson · Post by **Chris Peterson** » Sat Oct 06, 2012 5:39 pm

bystander wrote:Yes, Chris, I am very aware of that. I guess the sarcasm was lost on you.

Not entirely (although sarcasm can be difficult to detect, sometimes). I know you well enough to know that you aren't a "it's just a theory" kind of guy... but didn't think that expanding on your comments couldn't be helpful. Although I was responding to your comment, I wasn't actually responding to you... just using what you said as a jumping off point.

Ann · Post by **Ann** » Sat Oct 06, 2012 5:53 pm

bystander wrote:
Ann wrote:To my knowledge there is no evidence of any sort of black hole in the Orion Nebula.

One of the links in the caption of today's APOD does talk about a possible black hole in the Orion Nebula, yes. The link takes us to an astronomical paper written by Ladislav Subr (Prague), Pavel Kroupa (Bonn) and Holger Baumgardt (Queensland). In the abstract (the summary of the article), the authors wrote:

We speculate that the runaway-mass star may have collapsed directly into a massive black hole (Mbh > 100Msun).
The authors speculate that there might be a black hole in the Orion Nebula, but I have never heard anyone else back up that view. Please note that the black hole would have formed in an unusual way, by a direct collapse with no ensuing explosion. To my knowledge, there exists no hard evidence that a black hole has ever formed that way, certainly not in the present-day universe.

Ann
Astrophysicists speculate there is a supermassive black hole at the heart of the Milky Way, but no one has ever seen it. With an article published in The Astrophysical Journal, I can only assume the authors' speculation of a black hole in the Orion Nebula is backed up with persuasive evidence. What scientists mean by speculation is very different than the common usage of the term. After all, gravity is only a theory.

Fascinating, bystander. I have never questioned the presence of a supermassive black hole in the center of the Milky Way.

Perhaps your train of thoughts went off on a neufer-like tangent when you saw my post about the Orion Nebula.

As it is in the core of the Milky Way, so it is in the Orion Nebula?

Ann

BDanielMayfield · Post by **BDanielMayfield** » Sat Oct 06, 2012 6:06 pm

To Ann, bystander and Chris, I think that there may be at least two lines of "evidence," though unconfirmed as yet, for this proposed Orion black hole. (1) The high velocities of the four very bright and therefore very massive Trapezium stars. What has accelerated them? (2) It is suggested that for a gas/dust cloud of Orion's size there should have been about four times as many O & B stars as are observed. What accounts for this shortage? This black hole theory is suggested as an explanation for these observations.

Bruce

Beyond · Post by **Beyond** » Sat Oct 06, 2012 6:25 pm

Perhaps some more Disney science (friction) movies will help

bystander · Post by **bystander** » Sat Oct 06, 2012 6:26 pm

Ann wrote:Fascinating, bystander. I have never questioned the presence of a supermassive black hole in the center of the Milky Way.

Perhaps your train of thoughts went off on a neufer-like tangent when you saw my post about the Orion Nebula.

No, my train of thought was well stated. I have no quarrel with the evidence for supermassive black holes at the heart of this galaxy or any other, nor am I likely to pick a fight with gravity. However, I am much more likely to give credence to the speculations of astrophysicists published in a peer reviewed journal than I am the ramblings of a school teacher.

neufer · Post by **neufer** » Sat Oct 06, 2012 6:31 pm

: [size=125][b]MACBETH:[i] Avaunt! and quit my sight! let the earth hide thee! Thy bones are marrowless, thy blood is cold; Thou hast no [color=#0000FF]SPECULATION[/color] in those eyes Which thou dost glare with![/i][/b][/size]

bystander wrote:
Astrophysicists speculate there is a supermassive black hole at the heart of the Milky Way, but no one has ever seen it. With an article published in The Astrophysical Journal, I can only assume the authors' speculation of a black hole in the Orion Nebula is backed up with persuasive evidence. What scientists mean by speculation is very different than the common usage of the term. After all, gravity is only a theory.

SPECULATE, v.i. [Webster's Dictionary (1828)]
[L. speculor, to view, to contemplate, from specio, to see.]

1. To meditate; to contemplate; to consider a subject by turning it in the mind and viewing it in its different aspects and relations.

2. To purchase land, goods, stock or other things, with the expectation of an advance in price, and of selling the articles with a profit by means of such advance; as, to SPECULATE in coffee, or in sugar, or in six percent stock, or in bank stock.
------------------------------------------------------

. Troilus and Cressida Act 3, Scene 3

ACHILLES: This is not strange, Ulysses.

. The beauty that is borne here in the face
. The bearer knows not, but commends itself
. To others' eyes; nor doth the eye itself,
. That most pure spirit of sense, behold itself,
. Not going from itself; but eye to eye opposed
. Salutes each other with each other's form;
. For SPECULATION turns not to itself,
. Till it hath travell'd and is mirror'd there
. Where it may see itself. This is not strange at all.
------------------------------------------------------
. King Henry V Act 4, Scene 2

Constable: 'Tis positive 'gainst all exceptions, lords,

. That our superfluous lackeys and our peasants,
. Who in unnecessary action swarm
. About our squares of battle, were enow
. To purge this field of such a hilding foe,
. Though we upon this mountain's basis by
. Took stand for idle SPECULATION:
. But that our honours must not. What's to say?
. A very little little let us do.
. And all is done. Then let the trumpets sound
. The tucket sonance and the note to mount;
. For our approach shall so much dare the field
. That England shall couch down in fear and yield.
------------------------------------------------------

Chris Peterson · Post by **Chris Peterson** » Sat Oct 06, 2012 6:34 pm

BDanielMayfield wrote:To Ann, bystander and Chris, I think that there may be at least two lines of "evidence," though unconfirmed as yet, for this proposed Orion black hole. (1) The high velocities of the four very bright and therefore very massive Trapazim stars. What has accerated them? (2) It is suggested that for a gas/dust cloud of Orion's size there should have been about four times as many O & B stars as are observed. What accounts for this shortage? This black hole theory is suggested as an explanation for these observations.

Having read no papers on the subject, I really have no opinion one way or the other. I certainly see no obvious reason why a black hole couldn't form by accretion inside a rich cluster. Neither am I aware of any cases of that happening being identified.

My comments were really directed towards what the effect of such a black hole would be on the dynamics of the cluster, and I think it would be quite small. So the absence of obvious dramatic effects does not strike me as evidence against a black hole being present.

Ann · Post by **Ann** » Sat Oct 06, 2012 6:52 pm

I am, of course, not saying that there can't possibly be a black hole in the Orion Nebula. Such a claim from someone like me would be very silly.

I'm just saying that a black hole of 150 solar masses is quite large as "small" black holes go. Compare it with Cygnus X-1, the best-known stellar mass black hole in the Milky Way. Its mass is about 14.8 solar masses, an order of magnitude less than the proposed black hole in the Orion Nebula.

In a recent Sky & Telescope News blog, Monica Young wrote that two stellar-mass black holes have been found in globular cluster M22. I assume that the term "stellar-mass black holes" refers to black holes with masses around twenty solar masses or so.

Globular clusters are tremendous and extremely old clusters. When they were newborn, they must have been several orders of magnitude more massive than the Trapezium Cluster in the Orion Nebula. There must have been an extreme amount of stellar collisions and binary pin-ball swapping inside these awesome "star cities". Yet the comparatively puny Trapezium would spawn a black hole that is much larger than what is found inside globular cluster M22?

I'm not saying that there isn't a black hole inside the Orion Nebula. Clearly I can't know anything about that. I'm not even saying that there can't be a 150-solar-mass black hole in the Orion Nebula. I'm just saying that the suggestion strikes me as most remarkable, and I would like to some additional evidence backing up this idea before I fully accept it.

Ann

owlice · Post by **owlice** » Sat Oct 06, 2012 7:06 pm

Ann, did you even read the paper the APOD links to before you posted? It appears you got only as far as the abstract and ignored the paper itself! I'm reminded of the Mad Hatter: "You can always take more than nothing." And that is what it appears the additional information you ask for would be: more than the nothing you currently have.

bystander · Post by **bystander** » Sat Oct 06, 2012 7:08 pm

Ann wrote:In a recent Sky & Telescope News blog, Monica Young wrote that two stellar-mass black holes have been found in globular cluster M22.

http://asterisk.apod.com/viewtopic.php?t=29676

There is also a recent discovery of a rare x-ray nova that produced a black hole in our galaxy that wasn't evident in the visible spectrum.

http://asterisk.apod.com/viewtopic.php?t=29698

Boomer12k · Post by **Boomer12k** » Sat Oct 06, 2012 9:48 pm

I like the detail Hubble can show us.

Thanks for the Crop view...AWESOME...

I see these globs all over the place...lower left, and bottom by the blue star. Reminds me of the globs in the space shots in the movie "Barbarella".

Then there is the furry places, and the roiling places....this place is just SEETHING...

M42 is probably my most favorite object in the night sky. My photos, with my 10" Meade and DSI 2 camera, might not be as detailed, but I can see many of the same structures. And these are short exposures of maybe 5-15 seconds. There is an interesting blue star, far right near the bottom, with a large "streamer" around it, and a Bow Shock??? Not really sure if that is what it is...Globs, streamers, striations, and at 4 o'clock from the Trapezium is a Lion's Head...

I don't know if this is exactly what the Human Eye would see...but if it is...I want to put a RESTAURANT and Resort Hotel there....I'm gonna be RICH!!!!!

I could tell you what else it reminds me of...but bystander would censor it...sorry for the other day....my bad....

Where does all that momentum energy being transferred into speed come from ? Well...The moon is pulling away from the Earth at about one inch per year. It is a transference of energy from the Earth. The Rotation mostly, I think I saw on one show. The Universe, I think. So, the MOON started CLOSER to the Earth....Well, these massive stars...being in close proximity to one another can be doing the same thing. Adding, sharing and evening out, their momentums together, and adding to each others speeds...Which over time increases. So the Cluster EXPANDS...just as the Earth/Moon system is expanding. The more speed... the farther out it orbits. We see this phenomena in other star clusters...after they form...the stars move away from one another. Like shot from a shotgun, the pellets move outward away from one another from the pressure change from barrel to air, not gravity from a nearby object...As closely packed stars transfer and share their momentum, kinetic energy, with each other, they speed up and spread out....(my take on this)

We don't have a BH near us "pulling" on the Moon that I know of. I am not saying there is not a BH in the Trapezium. But there is another POSSIBLE explanation, and other examples of systems doing the same concept...and yes, they may have some anomalies that suggest a black hole by deduction...not saying it is not so...just offering the other example and explanation.

As for the SMBH at the Center of the MW galaxy goes...The picture of the Maelstrom at the center of the galaxy...pretty much did it for me...Second picture down....
http://www.dailymail.co.uk/sciencetech/ ... ystem.html

Would not want to be in that hurricane of annihilation, restaurant or not....

:---[===] *

: I turned the picture to make it today's APOD view.

BDanielMayfield · Post by **BDanielMayfield** » Sat Oct 06, 2012 11:43 pm

After thinking about this Black Hole in Orion idea and discussing it with others to the point of having my intial skepticism (which was exactly like Ann's reaction at first) melted away I submitted a post on another blog and called it "The Goldilocks Princple":

Ok, so let’s assume that this ONC black hole idea is true and that furthermore it provides an example of the way open star cluster forming dust/gas clouds of this size generally evolve in this galaxy and others. Just as stars are spoken of as having habitability zones, galaxies also have zones that are more conducive to having earthlike planets that can remain unaffected by some astronomical terminal disaster for immense periods of time. These areas have the right range of metals ejected from earlier supernova and such, but too many supernova, and there goes the neighborhood, so to speak. That being said, in terms of long term habitability for the earth, which would you prefer to have 1300 light-years away, an open cluster dispersing 40 O & B stars, all of whom are destined to pop at some point, or 10 OB stars and a 150 solar mass black hole 1300 light years away? We could call this the Goldilocks Principle; if choosing between ideas about how the universe works, the side more favorable to life as we know it may be more likely to be found to be true. Therefore I like the implications of the simulations Subr et al have ran, and I think that they might be on to something, now that Dr. Young has explained why the evidence for the black hole is so hard to find.

On the other hand I think Ann's reasons for doubting this "speculation" are valid. This remains one of the many, many reasons why we need more and bigger telescopes.

Bruce

Killer Wolf · Post by **Killer Wolf** » Sun Oct 07, 2012 7:05 am

Thanks for the info.

that's interesting, Chris - not just Disney, but most other stuff i've come across says black holes have such gravitational pull they are a real danger.

Starship Asterisk*

APOD: At the Heart of Orion (2012 Oct 06)

APOD: At the Heart of Orion (2012 Oct 06)

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