Slashdot Mirror
Scientists Spot Rare 'In Between' Black Hole
An anonymous reader writes "Scientists have found a doomed star orbiting what appears to be a medium-sized black hole. This black hole appears to be a theorized 'in-between' category of black hole that has eluded confirmation and frustrated scientists for more than a decade."
...gray hole?
Authority questions you. Return the favor.
The link leads to some sort of science blog. An interesting discovery none the less.
Ah, you found me!
It's a trap!
[Fuck Beta]
o0t!
saved for posterity before it gets slashdotted
Dying Star Reveals More Evidence for New Kind of Black Hole
Submitted by BJS on Sun, 2006-01-08 11:58.
Posted in space | login or register to post comments | printer friendly page
Scientists using NASA's Rossi X-ray Timing Explorer have found a doomed star orbiting what appears to be a medium-sized black hole - a theorized "in-between" category of black hole that has eluded confirmation and frustrated scientists for more than a decade.
With the discovery of the star and its orbital period, scientists are now one step away from measuring the mass of such a black hole, a step which would help verify its existence. The star's period and location already fit into the main theory of how these black holes could form.
A team led by Prof. Philip Kaaret of the University of Iowa, Iowa City, announced these results today in Science Express. The results will also appear in the Jan. 27 issue of Science.
"We caught this otherwise ordinary star in a unique stage in its evolution, toward the end of its life when it has bloated into a red giant phase," said Kaaret. "As a result, gas from the star is spilling into the black hole, causing the whole region to light up. This is a well-studied region of the sky, and we spotted the star with a little luck and a lot of perseverance."
A black hole is an object so dense and with a gravitational force so intense that nothing, not even light, can escape its pull once within its boundary. A black hole region becomes visible when matter falls toward it and heats to high temperatures. This light is emitted before the matter crosses the border, called the event horizon.
Our galaxy is filled with millions of stellar-mass black holes, each with the mass of a few suns. These form from the collapse of very massive stars. Most galaxies possess at their core a supermassive black hole, containing the mass of millions to billions of suns confined to a region no larger than our solar system. Scientists do not know how these form, but it likely entails the collapse of enormous quantities of primordial gas.
"In the past decade, several satellites have found evidence of a new class of black holes, which could be between 100 and 10,000 solar masses," said Dr. Jean Swank, Rossi Explorer project scientist at NASA's Goddard Space Flight Center, Greenbelt, Md. "There has been debate about the masses and how these black holes would form. Rossi has provided major new insight."
These suspected mid-mass black holes are called ultra-luminous X-ray objects because they are bright sources of X-rays. In fact, most of these black hole mass estimates have been based solely on a calculation of how strong a gravitational pull is needed to produce light of a given intensity.
Kaaret's group at the University of Iowa, which includes Prof. Cornelia Lang and Melanie Simet, an undergraduate, made a measurement that can be used in the equation to directly calculate mass. Using straightforward Newtonian physics, scientists can calculate an object's mass once they know an orbital period and velocity of smaller objects rotating around it.
"We found a rise and fall in X-ray light every 62 days, likely caused by the orbit of the companion star around the black hole," said Simet. "The velocity will be hard to determine, however, because the star is located in such a dust-obscured area. This makes it hard for optical and infrared telescopes to observe the star and make velocity calculations. Yet for now, knowing just the orbital period is very revealing."
The suspected mid-mass black hole, known as M82 X-1, is a well-studied ultra-luminous X-ray object in a nearby star cluster containing about a million stars packed into a region only about 100 light years across. A leading theory proposes that a multitude of star collisions over a short period in a crowded region will create a short-lived gigantic star that collapses into a 1,000-solar-mass black hole. The cluster near M82 X-1 has a high-enough density to f
No. I think "in between" is where the switch is stuck in the middle (i.e., "subl" or "she's gonna blow"). Either way, something bad is gonna happen.
OK, this question just occured to me. I'm sure there is an obvious answer that I am overlooking.
How do/did the heaviest elements, which are/were formed in the largest stars, escape from those stars that ultimately become/became neutron stars and black holes? I know that elements are flung out from the star via super novae, but wouldn't the heaviest elements be at the core of the star that remains? how would they get out? Shouldn't they all be trapped in the stellar remnants?
my pet machine
If stars had been given categories like 'Doomed', i think i'd have paid more attention in my astronomy course. What Would Chandrasekar Do?
-AlexC
The more we see the more we can understand, and the more questions occur.
Given the possible variation in black hole sizes this poses some interesting problems for long term space travel. Mini-holes will pose major danger during high speed travel unless some fast detection method is found. This has resonances with Arthur C Clarke's story about the star mangled spanner...
The ultraluminous x-ray source (ULX) in M82 has been identified as a possible intermediate mass black hole formed in stellar collisions in the super star cluster MGG 11. We find that the x-ray flux from M82 is modulated with a peak to peak amplitude corresponding to an isotropic luminosity of 2.4 x 10^40 erg s-1 in M82 and a period of 62.0 ± 2.5 days, which we interpret as the orbital period of the ULX binary. This orbital period implies that the mass donor star must be a giant or supergiant. Large mass transfer rates, sufficient to fuel the ULX, are expected for a giant phase mass donor in an x-ray binary. The giant phase has a short life time, indicating that we see the ULX in M82 in a brief and unusual period of its evolution.
---
Reading this and the article, I'm not sure if the claim is necessarily valid. What's to stop this being a smaller black hole, a smaller star orbiting closer (with the same period), and beamed emission? An intermediate black hole is still the simplest explanation, but doesn't seem unique.
I quit!
I heard that there used to be plenty of those in the .cx domain.
Physics makes the world go 'round.
Here is the coral link http://www.scienceblog.com.nyud.net:8090/cms/dying _star_reveals_more_evidence_for_new_kind_of_black_ hole_9685
They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety.
... Breakfast and lunch ?
Hmm, maybe they did spot it inbetween breakfast and lunch, the statistics of that happening are high.
A slashdotting - you get the stick first and then the carrot !
What scientists spotted it? What scientists were frustrated? I'm really tired of stories sourced to 'scientists' and 'officials'. I'm sure that TFA has some of the material that I want, but that's not the point. On a by-the-word basis, the internet is, for all intents and purposes, free. Putting 5-7 words of additional information in the story wouldn't break the bank and it would really make this thing feel less lazy.
Elements heavier than iron consume more energy in their creation than their fusion process gives off. But that does not mean that they are not formed in a normal star's process. It just means that only a little of them are formed in a star's normal process. Stars do not fuse elements that produce energy in fusion, they fuse elements. The primary star energy is from hydrogen and helium fusion. The neutron flux, as well as the rest of the atoms hitting one another, can result in fusion. if two atoms hit each other in a way that will result in fusion, then they fuse. There are not a lot of iron atoms moving around fast enough to fuse with neutrons, hydrogen or helium, and some of the isotopes formed are radioactive. Since this is all going on in the core of the star, we will not see much evidence of it.
wake up and hold your nose
Now we just have to keep an eye on it for the next 10 million years or so to see what happens. Stay tuned!
Speaking of keeping an eye on it, has anyone managed to find any actual pictures?
https://www.eff.org/https-everywhere
They reckon it's a massive black hole because it's bright. Black holes that give off a lot of light have to be massive, because of something called the Eddington Limit.
However, it's just a dot in the sky, you can't tell how much energy in total is being given out just by measuring how much is coming in the direction of Earth - you don't know if it's a 60W lightbulb shining in all directions or a 5W torch pointing at you. For instance, black holes can have jets (rather like pulsars) and a smaller black hole with a jet pointing at Earth could explain their observation.
Discovering that it has a star orbiting it every two months doesn't change any of that, as far as I can tell.
I quit!
OK. I am also an astrophysicist, and I have been studying gravity in its string theory and loop quantum guises. Gravitational waves carry information, so they will *not* come out of a black hole horizon. However, gravity (as expressed in the theory of General Relativity) obeys what is called Gauss's law, which just means to say that it doesn't matter (!) what lies beneath the spherical BH horizon, or *any* imaginary sphere that surrounds it, gravity only depends upon the total mass (or equivalent energy) contained within. No gravitons need escape the BH horizon to create the gravity equivalent to the mass gobbled up by the hole.
- GRR
This line no sig