UKIRT discovers 'impossible' binary stars

Jul 05, 2012
This artist's impression shows the tightest of the new record breaking binary systems. Two active M4 type red dwarfs orbit each other every 2.5 hours, as they continue to spiral inwards. Eventually they will coalesce into a single star. Credit: J. Pinfield, for the RoPACS network

(Phys.org) -- A team of astronomers have used the United Kingdom Infrared Telescope (UKIRT) on Hawaii to discover four pairs of stars that orbit each other in less than 4 hours. Until now it was thought that such close-in binary stars could not exist. The new discoveries come from the telescope's Wide Field Camera (WFCAM) Transit Survey, and appear in the journal Monthly Notices of the Royal Astronomical Society.

About half of the stars in our are, unlike our Sun, part of a binary system in which two stars orbit each other. Most likely, the stars in these systems were formed close together and have been in orbit around each other from birth onwards. It was always thought that if form too close to each other, they would quickly merge into one single, bigger star. This was in line with many observations taken over the showing the abundant population of stellar binaries, but none with orbital periods shorter than 5 hours.

For the first time, the team have investigated binaries of , stars up to ten times smaller and a thousand times less luminous than the Sun. Although they form the most common type of star in the Milky Way, red dwarfs do not show up in normal surveys because of their dimness in visible light.

For the last five years, UKIRT has been monitoring the brightness of hundreds of thousands of stars, including thousands of red dwarfs, in near-infrared light, using its state-of-the-art (WFC). This study of cool stars in the time domain has been a focus of the European (FP7) Initial Training Network ' Around Cool Stars' (RoPACS) which studies planets and cool stars.

"To our complete surprise, we found several red dwarf binaries with orbital periods significantly shorter than the 5 hour cut-off found for Sun-like stars, something previously thought to be impossible", said Bas Nefs from Leiden Observatory in the Netherlands, lead author of the paper. "It means that we have to rethink how these close-in binaries form and evolve."

Since stars shrink in size early in their lifetime, the fact that these very tight binaries exist means that their orbits must also have shrunk as well since their birth, otherwise the stars would have been in contact early on and have merged. However, it is not at all clear how these orbits could have shrunk by so much.

One possible answer to this riddle is that cool stars in binary systems are much more active and violent than previously thought.

It is possible that the magnetic field lines radiating out from the cool star companions get twisted and deformed as they spiral in towards each other, generating the extra activity through stellar wind, explosive flaring and star spots. Powerful magnetic activity could apply the brakes to these spinning stars, slowing them down so that they move closer together.

"Without UKIRT's superb sensitivity, it wouldn't have been possible to find these extraordinary pairs of red dwarfs", said David Pinfield. He adds: "The active nature of these stars and their apparently powerful magnetic fields has profound implications for the environments around red dwarfs throughout our Galaxy."

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kevinrtrs
1.9 / 5 (23) Jul 05, 2012
To our complete surprise,....It means that we have to rethink how these close-in binaries form and evolve

Seems like this is the norm with most observations these days.

It means that the nebular theory of star formation now has so many ad-hoc add-ons it's beginning to look like the geocentric theory of old. This is confirmed by this statement
"However, it is not at all clear how these orbits could have shrunk by so much.
One possible answer to this riddle is that cool stars in binary systems are much more active and violent than previously thought.".


Lurker2358
1.5 / 5 (8) Jul 05, 2012
It is possible that the magnetic field lines radiating out from the cool star companions get twisted and deformed as they spiral in towards each other, generating the extra activity through stellar wind, explosive flaring and star spots. Powerful magnetic activity could apply the brakes to these spinning stars, slowing them down so that they move closer together.


As a general rule, conservation of angular momentum should prevent such activities from significantly influencing the orbits.

You'd need at least a 5 to 10% mass transfer in order to change the gravitation of the system enough to cause one of the stars to fall towards the other due to a denser gravity field.

Accomplishing such a large mass transfer typically requires a large collision or a supernova, and red dwarfs aren't large enough to cause a supernova, so you'd need to figure out some other explanation for transferring that much mass.
Lurker2358
2.2 / 5 (10) Jul 05, 2012
On the other hand, it depends on your definition of a "stable orbit".

If an orbit was at 1a.u. and decayed by 10m per year, then after 10 billion years it would decay by 10 billion meters, or 10 million kilometers, without even applying the increase in acceleration due to closer proximity as time goes by.

So 10 to 100 meters per year worth of decay is all you need to explain this. It would seem mostly stable from our position, since we couldn't possibly measure that, at least not over a matter of a few years any, from the earth. It would take a few hundred years worth of observation to detect and confirm that with our existing technology.
katesisco
1 / 5 (7) Jul 05, 2012
Actually I think it is more like a deteriorating magnetic blanket; the more neutrinos that bleed off, the more the material is able to fall into the next level. I think the 'densest material possible -- George Gamow' is held in that guantum state by the strongest possible magnetic field which cannot fail to deteoriate over time. As it does so, the material passes into the next state losing it quantum synchronisity. Eventually it moves into a regular atomic state which to me explains liquid water in space.
We public are treated to the current view of the elephant, side, ears, tusk, etc.
Jeddy_Mctedder
2.3 / 5 (6) Jul 05, 2012
ive been following astronomy abstracts for 7 years on physorg, maybe 8 .

over the years i've come to believe that, of all areas of science, astronomy is definitely going to be the area most likely to have to be seriously rethought due to the likelihood of paradigm upending observations being achieved with better telescopes and computers, why?

in no other science are we studying so much at once, and in no other science do we know that our future tools used in that area of science are going to be predictably more powerful. better telescopes are expensive on some level, but no where near the cost of 'big science' in particle physics , and more importantly better telescopes are going to yield much higher sensitivity and if there IS something out there we cannot see, we will be able to see it in the future.

i'm starting to think we are on the verge of a big breakthrough in astronomy personally. the next 20 years should be quite a ride.
aroc91
4.4 / 5 (10) Jul 05, 2012
To our complete surprise,....It means that we have to rethink how these close-in binaries form and evolve

Seems like this is the norm with most observations these days.

It means that the nebular theory of star formation now has so many ad-hoc add-ons it's beginning to look like the geocentric theory of old. This is confirmed by this statement
"However, it is not at all clear how these orbits could have shrunk by so much.
One possible answer to this riddle is that cool stars in binary systems are much more active and violent than previously thought.".




Still doesn't mean the Earth is 6000 years old, kevin.
Torbjorn_Larsson_OM
2.2 / 5 (5) Jul 05, 2012
Nice! Not so nice for astrobiology observations around red dwarfs, if the solar activity is the culprit. But more variety means more opportunities for life!

Creationists shouldn't comment on science, hilarious. "A new observation improving science - therefore magical gods." I have this bridge here that I can sell to creationists really cheap...
TheGhostofOtto1923
4.3 / 5 (14) Jul 05, 2012
To our complete surprise,....It means that we have to rethink how these close-in binaries form and evolve
Seems like this is the norm with most observations these days.
-But you guys never have to rethink anything do you? DESPITE whatever new evidence comes along to make your explanations even more untenable.

But this is faith, yes? Certainty despite evidence.
It means that the nebular theory of star formation now has so many ad-hoc add-ons it's beginning to look like the geocentric theory of old. This is confirmed by this statement
Naw it just means scientists are gaining a better understanding of how things work. It is very comforting to know that they are more and more willing to rethink old assumptions yes? This too is progress. The sort of progress religion NEVER makes.
brant
not rated yet Jul 06, 2012
I predict they will find stars that orbit each other with a shorter period.
malapropism
5 / 5 (5) Jul 06, 2012
To our complete surprise,....It means that we have to rethink how these close-in binaries form and evolve

Seems like this is the norm with most observations these days.

Indeed and with improvements in the observing technologies being developed and deployed at a pretty rapid pace what else would you expect?
It means that the nebular theory of star formation now has so many ad-hoc add-ons it's beginning to look like the geocentric theory of old. This is confirmed by this statement
"However, it is not at all clear how these orbits could have shrunk by so much.
One possible answer to this riddle is that cool stars in binary systems are much more active and violent than previously thought.".

No, it doesn't mean that at all. This is indeed 1 possible answer. Nowhere in the article does it say that the scientists think it is THE answer, unlike the dogma you espouse. Suggesting and then testing possible answers is simply good science.
rubberman
1 / 5 (2) Jul 06, 2012
I predict they will find stars that orbit each other with a shorter period.


Ones that are closer to amalgamation, possibly...but 21/2 hours is pretty tight.
HannesAlfven
1.6 / 5 (7) Jul 06, 2012
The more elusive a concept is to our senses, the more cautious we should be with regards to those scientific domains which study it, for what the principle of hermaneutics suggests is that humans will fill in whatever blind spots our senses leave us with, with our own pre-existing social, psychological and cultural context. What this means is that if you are a religious person, you will find God in ambiguity. If you are a mathematician, you will look for mathematical glue. If a person has refused to read anything outside of conventional theories, they will seek out ideas which permit that gamble to live on. If a person is not averse to divergent theories, they will be more willing to infer an against-the-mainstream theory.

Those who prefer to imagine that sociology and psychology have nothing to do with science are treating science like it's a religion. We are humans, and hermaneutics is the tool our minds use to deal with ambiguity.

Critical thinking is the ONLY way out, guys.
HannesAlfven
2 / 5 (8) Jul 06, 2012
Re: "It means that the nebular theory of star formation now has so many ad-hoc add-ons it's beginning to look like the geocentric theory of old ... Naw it just means scientists are gaining a better understanding of how things work"

This is where you guys go overboard: Each time that a surprise occurs, and the models are updated, an old theory was shown to be incorrect. That's the definition of ad hoc modeling, and those who try to sugarcoat this process do no service to science.

As people age, the ad hoc modeling game gets old. I suspect that the more gung-ho advocates of the mainstream ad hoc modeling approach tend to be younger. But, with just a little bit of foresight and introspection, you could easily place yourself 20 or 30 years into the future of your own life, and imagine that this same exact thing is STILL going on then.

At what point do you say, "Enough is enough! I want to see real progress before my turn is up."

There is no going back when you place just one bet.
HannesAlfven
1.7 / 5 (6) Jul 06, 2012
Re: "i'm starting to think we are on the verge of a big breakthrough in astronomy personally. the next 20 years should be quite a ride."

The biggest impediment to progress in the space sciences will not come from outsiders. It will come from those who adopt an incomplete specialist's perspective, and refuse to critically think about the textbook materials they've memorized. Critical thinking does not occur in the absence of a wide breadth of conceptual comprehension, and studies are extremely clear (YouTube: Eric Mazur) that students don't understand the concepts of physics today sufficient to question them. So, what you will see is knee-jerk defense of dying paradigms, and this can go on for literally hundreds of years if we let it.

The first step to fixing science is to fix science education. We have to encourage people to learn the concepts of science. It doesn't have to happen in our university system. If the science journalists wanted to, they could fix the problem.
Deathclock
2.7 / 5 (7) Jul 06, 2012
To our complete surprise,....It means that we have to rethink how these close-in binaries form and evolve

Seems like this is the norm with most observations these days.

It means that the nebular theory of star formation now has so many ad-hoc add-ons it's beginning to look like the geocentric theory of old. This is confirmed by this statement
"However, it is not at all clear how these orbits could have shrunk by so much.
One possible answer to this riddle is that cool stars in binary systems are much more active and violent than previously thought.".




Kevin just got back from Jupiter. He went there to get more stupider... mission accomplished!
Whatwhat
1 / 5 (2) Jul 07, 2012
The biggest impediment to progress in the space sciences will not come from outsiders. It will come from those who adopt an incomplete specialist's perspective, and refuse to critically think about the textbook materials they've memorized. Critical thinking does not occur in the absence of a wide breadth of conceptual comprehension, and studies are extremely clear (YouTube: Eric Mazur) that students don't understand the concepts of physics today sufficient to question them. So, what you will see is knee-jerk defense of dying paradigms, and this can go on for literally hundreds of years if we let it.


Encourage competing theories and score them based on their predictive ability with a higher value given if it's novel. That would probably create a whole new meta-science field which would be worth it in exchange for multiple perspectives. Healthy competition is a good means to innovation and advancement and it would create new ideas about different concepts and problems.
Job001
1 / 5 (4) Jul 07, 2012
Surprise is normal! Reality isn't limited to Ocam's razor minimalist models. Reality is complex, data expands, the correlation residual grows and the unknown astounds. The multiverse theory illuminates the unknown 10^500 extensible vs the known. The universe used to be 3000 stars, then 100 billion, now 10,000 billion billion observable and 10^500 as multiverse theory. Science has a fault of assuming the simplest model is best. Why be surprised?
jsdarkdestruction
5 / 5 (1) Jul 09, 2012
"Science has a fault of assuming the simplest model is best. Why be surprised?"
barring evidence of a more complex theory....can you prove the multiverse? If you had sound proof of it scientists would happily adopt it. nothing against multiverse hypothesis but its true. no flawed thinking there....do you propose we base/accept models based on conjecture instead of the evidence currently available?