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Digitized Sky Survey, STScI/AURA, Palomar / Caltech, and UKSTU / AAO
This Digitized Sky Survey image shows the oldest star with a well-determined age in our galaxy. Called the Methuselah star, HD 140283 is 190.1 light-years away. Astronomers refined the star's age to about 14.5 billion years (which is older than the universe), plus or minus 800 million years.
By Mike Wall
Space.com
The oldest known star appears to be older than the universe itself, but a new study is helping to clear up this seeming paradox.
Previous research had estimated that the Milky Way galaxy's so-called "Methuselah star" is up to 16 billion years old. That's a problem, since most researchers agree that the Big Bang that created the universe occurred about 13.8 billion years ago.
Now a team of astronomers has derived a new, less nonsensical age for the Methuselah star, incorporating information about its distance, brightness, composition and structure.
"Put all of those ingredients together, and you get an age of 14.5 billion years, with a residual uncertainty that makes the star's age compatible with the age of the universe," study lead author Howard Bond of Pennsylvania State University and the Space Telescope Science Institute in Baltimore said in a statement. [Gallery: The Methuselah Star Revealed]
The uncertainty Bond refers to is plus or minus 800 million years, which means the star could actually be 13.7 billion years old — younger than the universe as it's currently understood, though just barely.
A mysterious, fast-moving star
Bond and his team used NASA's Hubble Space Telescope to study the Methuselah star, which is more formally known as HD 140283.
A. Fujii and Z. Levay (STScI)
This is a backyard view of the sky surrounding the ancient star, cataloged as HD 140283, which lies 190.1 light-years from Earth. The star is the oldest known to astronomers to date.
Scientists have known about HD 140283 for more than 100 years, since it cruises across the sky at a relatively rapid clip. The star moves at about 800,000 mph (1.3 million km/h) and covers the width of the full moon in the sky every 1,500 years or so, researchers said.
The star is just passing through the Earth's neck of the galactic woods and will eventually rocket back out to the Milky Way's halo, a population of ancient stars that surrounds the galaxy's familiar spiral disk.
The Methuselah star, which is just now bloating into a red giant, was probably born in a dwarf galaxy that the nascent Milky Way gobbled up more than 12 billion years ago, researchers said. The star's long, looping orbit is likely a residue of that dramatic act of cannibalism.
Distance makes the difference
Hubble's measurements allowed the astronomers to refine the distance to HD 140283 using the principle of parallax, in which a change in an observers' position — in this case, Hubble's varying position in Earth orbit — translates into a shift in the apparent position of an object.
They found that Methuselah lies 190.1 light-years away. With the star's distance known more precisely, the team was able to work out Methuselah's intrinsic brightness, a necessity for determining its age.
The scientists also applied current theory to learn more about the Methuselah star's burn rate, composition and internal structure, which also shed light on its likely age. For example, HD 140283 has a relatively high oxygen-to-iron ratio, which brings the star's age down from some of the earlier predictions, researchers said.
In the end, the astronomers estimated that HD 140283 was born 14.5 billion years ago, plus or minus 800 million years. Further observations should help bring the Methuselah star's age down even further, making it unequivocally younger than the universe, researchers said.
The new study was published last month in the Astrophysical Journal Letters.
Follow Mike Wall @michaeldwall. Follow us @Spacedotcom, Facebook or Google+. Originally published on Space.com.
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I'm not an astrophysicists but if the star has iron in it that would make it a second generation star. Which would mean that it can't be nearly as old as they're saying. Either I'm missing something or the article is getting some of their reporting wrong.
That brings up a question in my mind that I can't satisfy with a few quick searches... Can a Population III star form Iron? I would think given the mass that these stars would need to form since they are metal poor they could but I haven't seen anything that says outright that they can.
@east coast - Yes, they can. I found the following for you in wikipedia under 'Metallicity'
Thanks, elentir!
Michael! Where are you when you are needed?
Oh, back to the original point...
Ok, so it's a second generation star. Why can't it be that old? By mostly accepted timelines there is no reason it can't be a Population II star. Population III stars probably didn't exist for very long. Maybe a couple million years, given their mass. I don't even think there is an accepted age of the universe that would make that small of a number improbable.
Wha? Huh? (Wipes sleep from eyes after long night at the observatory....)
What Elentir sayz, plus - I wish these articles more prominently mentioned the error bars on whatever number these stories talk about. Some numbers - like the age of the Universe - we think we have a pretty good handle on (thanks to the study of the cosmic microwave background), while others - such as the age of a star - have some pretty gosh darn large ranges....
Right, heavier elements aren't found in the first stars. All the pure hydrogen stars burned out very quickly.
That's one of the reasons they revised the age.
This seems to be a rather unusual star whose high speed and long distance of travel enables it to continually feed on more fuel, so it never runs out of fuel to burn. I don't see why this could not also enable this star to feed on other elements not normally found in first generation stars, too. - RC
because the Universe "must" be 13.8 billion years old.
Seems to me, the likely hood that the calculations for both, star and universe, will always be tweakableso as to fit the needed model of the time.
It's not tweaked to fit the model, rather that it's tweaked to fit the observations/evidence. If new evidence shows the model is wrong, the model is tweaked or discarded.
For this star's age, the previous age estimates were based on less certain observations. As the article states, scientists obtained more accurate observations about the star allowing them to adjust their estimate and make it more accurate. Same thing goes with the age of the universe. Scientists currently have strong evidence for estimating the age at it's current value. Of course, as with all science, new evidence could always come to light that would force scientists to reevaluate those values. But as more evidence comes in, the more confident scientists become in those values. Note that scientists usually build into those ages a margin of error to account for these uncertainties.
the sooner you realize that the knowlege you possess about the universe is so riddled with holes that you might as well start over.....the better off you'll be.
You might be better off with the knowledge of how to spell knowledge.
Of course it's riddled with holes. That is why we keep searching, seeking and experimenting. That's the whole point to doing science :- because our knowledge is full of holes.
Yes on the holes, no on starting over. I see no reason to throw out Newton with the bath water (so to speak), but I'm sure tickled that Einstein did such a wonderful job of adding to Ike's Universe.
Jawohl!
Sooner or later a good conversation turns to personal insults.
Too bad it's out of our reach. Imagine sampling the particles being emitted from that star... they might tell us more about the early universe.
Someday that probe will be on its way....
Michael - Hopefully we can figure out superluminal space travel or manage to get there before the star goes nova... I thinks its well into in the red giant phase now.
If the mass of the star is near our own sun's, it can become a red giant but it can't become a nova.
.6 solar mass, so correct on no nova. It would be nice to get a closer look before it fizzles, though....
arghh... missed that ".6 solar mass" part.
You didn't miss it, David - I had to go look it up. ;-)
Ok, so if "someone" got you a ride on "something" that could overtake Voyager I or II within ten years (totally achievable with exsting technology), tell us what instrumentation suite you would have aboard??
Oh - fun! Instead of V1 OR V2, could we go for BOTH? (Rubbing greedy hands together!!!)
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Off Topic - COMMENT TRACKING IS FINALLY WORKING AGAIN! At least, it's finally working for me, in this one article. I have really missed how that feature got lost in the new & "improved" NewsVine....
If you can't get a lateral sensor array, neutrino pulse detectors, hyperspace transmitter, and a coffee machine, then I'm stumped.
aren't each of the missions custom designed and engineered? I'm just blabbing but it seems to me that your most important requirements for long range missions are always going to be data collection [pictures, radiometers, magnetometers], computation, transmission, and housekeeping. As each area is constantly improving its technology, you just put in the best that you can find for each mission and cross your fingers.
Good thing I'm not in charge of these things.