Chandra finds Milky Way's black hole grazing on asteroids

Feb 08, 2012
A new study provides a possible explanation of mysterious X-ray flares detected by Chandra over the period of several years. It suggests that there is a cloud around Sgr A* containing trillions of asteroids and comets, stripped from their parent stars. The flares occur when asteroids of six miles or larger in radius are consumed by the black hole. The panel on the left shows a very long Chandra observation of the region around the Sgr A*, while the three panels on the right are artist's impressions of the path that a doomed asteroid would take on its way to the black hole. Credit: X-ray: NASA/CXC/MIT/F. Baganoff et al.; Illustrations: NASA/CXC/M.Weiss

(PhysOrg.com) -- The giant black hole at the center of the Milky Way may be vaporizing and devouring asteroids, which could explain the frequent flares observed, according to astronomers using data from NASA's Chandra X-ray Observatory.

For several years Chandra has detected X-ray about once a day from the supermassive black hole known as Sagittarius A*, or "Sgr A*" for short. The flares last a few hours with brightness ranging from a few times to nearly one hundred times that of the black hole's regular output. The flares also have been seen in from ESO's Very Large Telescope in Chile.

"People have had doubts about whether asteroids could form at all in the near a ," said Kastytis Zubovas of the University of Leicester in the United Kingdom, and lead author of the report appearing in the . "It's exciting because our study suggests that a huge number of them are needed to produce these flares."

Zubovas and his colleagues suggest there is a cloud around Sgr A* containing trillions of asteroids and comets, stripped from their parent stars. Asteroids passing within about 100 million miles of the black hole, roughly the distance between the Earth and the sun, would be torn into pieces by the tidal forces from the black hole.

These fragments then would be vaporized by friction as they pass through the hot, thin gas flowing onto Sgr A*, similar to a meteor heating up and glowing as it falls through Earth's atmosphere. A flare is produced and the remains of the are swallowed eventually by the black hole.

"An asteroid's orbit can change if it ventures too close to a star or planet near Sgr A*," said co-author Sergei Nayakshin, also of the University of Leicester. "If it's thrown toward the black hole, it's doomed."

The authors estimate that it would take asteroids larger than about six miles in radius to generate the flares observed by Chandra. Meanwhile, Sgr A* also may be consuming smaller asteroids, but these would be difficult to spot because the flares they generate would be fainter.

These results reasonably agree with models estimating of how many asteroids are likely to be in this region, assuming that the number around stars near Earth is similar to the number surrounding stars near the center of the Milky Way.

"As a reality check, we worked out that a few trillion asteroids should have been removed by the black hole over the 10-billion-year lifetime of the galaxy," said co-author Sera Markoff of the University of Amsterdam in the Netherlands. "Only a small fraction of the total would have been consumed, so the supply of asteroids would hardly be depleted."

Planets thrown into orbits too close to Sgr A* also should be disrupted by tidal forces, although this would happen much less frequently than the disruption of asteroids, because planets are not as common. Such a scenario may have been responsible for a previous X-ray brightening of Sgr A* by about a factor of a million about a century ago. While this event happened many decades before X-ray telescopes existed, Chandra and other X-ray missions have seen evidence of an X-ray "light echo" reflecting off nearby clouds, providing a measure of the brightness and timing of the flare.

"This would be a sudden end to the planet's life, a much more dramatic fate than the planets in our solar system ever will experience," Zubovas said.

Very long observations of Sgr A* will be made with Chandra later in 2012 that will give valuable new information about the frequency and brightness of flares and should help to test the model proposed here to explain them. This work could improve understanding about the formation of asteroids and planets in the harsh environment of Sgr A*.

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User comments : 14

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Going
not rated yet Feb 08, 2012
Are the x-ray and infra red emissions synchronous?
jsdarkdestruction
3.7 / 5 (3) Feb 08, 2012
interesting. does tuxfords idol have a model to reflect this?
javjav
2.3 / 5 (3) Feb 08, 2012
In the left area of the X-ray image, I see a woman dressed in a white top. She must be tall, millions of light years in height, because she covers from top to bottom of the image. And she is dancing... Can other people see it or am I ill?
Vendicar_Decarian
3.7 / 5 (3) Feb 08, 2012
Clearly there is a dancing alien baby on the left. It's glowing eyes give it away.

And in the center there is a glowing white chicken about continue incubating it's bright blue egg.

Shelgeyr
1 / 5 (2) Feb 08, 2012
@javjav: You're not ill, not if her knees are pointed to the left, and her skirt's about the longest above-the-knees miniskirt imaginable... She's certainly rocking out to some celestial music, it seems.

If that's not the case, then maybe I'm seeing things.

Thank you for the power of suggestion!
MarkyMark
not rated yet Feb 09, 2012
Im worried for some rason that woman has a Foxes head!!! Am i ill? Or am i messing with your post ( i hope ) Furry minds?
Tuxford
1 / 5 (8) Feb 09, 2012
Why not consider a simpler explanation? The non-black core star is simply flaring due to the new energy and matter production therein. In the extreme case, it produces Fermi Bubbles, and superwave cosmic ray ejections that alter the activity of our sun, changing our climate, producing ice ages.

But, then, what would all those researchers do if this problem were suddenly solved? It must be asteroids! It just must be.....
jsdarkdestruction
5 / 5 (1) Feb 10, 2012
do you really think the scientific community never considered the possibility of the large amount of activity seen in the galatic centers being related to the creation of new matter tuxford?
antialias_physorg
5 / 5 (1) Feb 10, 2012
Why would the CREATION of matter even produce x-rays? Matter creation is a process in which you put in energy - not one which releases it.
Tuxford
1 / 5 (6) Feb 10, 2012
One must consider the possibility that our observable universe is subset of a larger underlying realm of undetectable something (particles?). That from this realm matter and energy can enter the observable universe given the proper underlying conditions. These conditions are enhanced in the presence of high mass density, such as within the cores of stars. Thus our observable universe is an open system, rather than closed.

In this model, observable particles are not objects, but rather self-sustaining reactions of the underlying (particles). This model comes from General Systems theory, applied to physics.
antialias_physorg
5 / 5 (3) Feb 10, 2012
One must consider the possibility that our observable universe is subset of a larger underlying realm of undetectable something

Must one? Why? Just because you say so?
Are you talking about gods? Because that is the exact same line of reasoning theists use.

If it's not detectable then it doesn't interact (because otherwise it would be detectable by the interaction). If its not detectable then for all intents ans purposes it doesn't apply to us.
Tuxford
1 / 5 (6) Feb 10, 2012
Ask yourself what is the mechanism that makes up a field or force, that makes it something other than a basic element of our universe. Something causes particles to interact that we define as a field or force. What are the actual mechanics that cause that effect?

It seems logical that the mechanics must be caused by something that by definition, cannot be observed directly, only inferred. That something is likely much smaller than the combined effect that we call a field or force.

General systems theory provides a model as to how this might be possible. It has nothing to do with religious faith. This is science. If you choose not to consider it, that is your choice.

The individual smaller something does not interact with anything via a field or force. However, the reaction of many of these smaller things taken together produces what we call a subatomic particle, which displays the characteristics of projecting fields and forces.
antialias_physorg
5 / 5 (3) Feb 11, 2012
It seems logical that the mechanics must be caused by something

a) Fields, particles and the like are MODELS.

b) Your notions of cause and effect is misguided. You're taking an analogy too far. Just because you experience cause-effect relationships on the human scale does not mean it works that way on all scales (on the quantum scale it doesn't - and there is mo reason to believe it works that way on any scale smaller than that). Again: "cause and effect" is a MODEL.
Tuxford
1 / 5 (2) Feb 12, 2012
To abandon the need to understand cause and effect relationships once a certain scale is reached, seems like a capitulation to magic. Do you believe in magic too? Do you have faith in a god almighty? Scary? Where does it end? Good luck with that....

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