Ancient Star Found, Estimated at 13.2 Billion Years Old

raguirre writes "An article on Physorg.org reports that a newly found star may be as old as the universe itself. Recent studies have concluded that the Big Bang occurred somewhere in the neighborhood of 13.7 Billion years ago. The star, a heavy-elements laden fossil labeled HE 1523-0901 on charts was probably born right around the same time; approximately 13.2 Billion years ago. 'Today, astronomer Anna Frebel of the the University of Texas at Austin McDonald Observatory and her colleagues have deduced the star's age based on the amounts of radioactive elements it contains compared to certain other "anchor" elements, specifically europium, osmium and iridium.'"

Re:Heavy elements?

[Beryllium Sphere(tm)]

You're right, and this is one of the confusing things about the writeup, especially since they call it a metal poor star near the beginning and say it's rich in radioactives later.

The Big Bang stopped more or less at helium, and things like uranium have to cook in non-equilibrium processes like supernovas.

500 million years is enough time for that to happen, since a supergiant star can race through its entire lifetime in a few million years. This could have formed from the remnants of one of the earliest supernovas, or it could be several generations old.

Re:Age of the universe.

[Anonymous Coward]

Why was this marked as a Troll. Some pastors and religious morons really do believe that.

Re:Heavy elements?

[Anonymous Coward]

Because of the higher density of the universe back then, the first few dozen generations of star were probably all super-massive giants that only have a lifespan of between 10 and 100 million years. The first supernova-generated elements were introduced to the universe very early, in fact production of them used to be orders of magnitudes higher at the beginning.

Re:Heavy elements?

[Graymalkin]

Supergiant and hypergiant stars (like Eta Carinae and SN 2006gy's progenitor) don't have long lifetimes and were likely prevalent in the early universe. Their deaths could have formed a lot of the heavy elements in HE 1523-0901. Five hundred million years is plenty of time for a lot of 100-120 solar mass giants to burn out and go supernova. It's likely the remnants of these early giants produced most of the stellar nurseries the next generation of less massive stars were born in.

Re:Old as the universe?

[DrJokepu]

Actually, not exactly. According to the Big Bang Theory, after the Bing Bang nucleosynthesis, almost no elements heavier than lithium have been formed. Most of the 'fundamental elements' as the parent said like carbon were not created until the formation of the first stars. According to the Wikipedia:

These stars fused heavier elements through stellar nucleosynthesis during their lives and through supernova nucleosynthesis as they died. The seeding of the interstellar medium by heavy elements eventually allowed the formation of terrestrial planets like the Earth.

Source: http://en.wikipedia.org/wiki/Atoms#Atoms_and_the_B ig_Bang_Theory [wikipedia.org]
So we are children of stars indeed.

Re:That was us

[HomelessInLaJolla]

a unique elemental composition?

Wow. You really don't know anything about the science behind this, do you?

Stars do not, for certain, have a unique elemental composition. They have a characteristic fingerprint of radiation which we interpret to correspond with various elemental compositions. The fact is that we've only recorded sets of photons and then drawn conclusions, some of them are well-founded but they are still interpreted conclusions nevertheless, about what elements those photons most likely were emitted from.

Recognizing that astronomical observers are recording radiation leads back to my initial explanation:

That the stars and galaxies look different is only because the pictures are taken at different angles...Imagine standing on the inside of an irregularly shaped egg with a perfectly reflective inner surface and looking around you

That perfectly reflective inner surface is irregularly shaped--like crinkled up aluminum foil. Take a piece of crinkled aluminum foil, spread it somewhat flat, and then begin looking at it from different angles. The pattern of colors reflected back to you will be different every time you change the angle--yet it's still the same piece of aluminum foil.

Re:I wonder

[gkhan1]

That theory is called the tired light theory [wikipedia.org] and has been thoroughly debunked. No scientist worth the name believes in it. I'm sorry to say it, but you're simply wrong on that one.

Re:Heavy elements?

[BungaDunga]

The big bang produced lots and lots of protons + electrons. Some got together and formed hydrogen and helium; beyond that, you need stars to produce heavier elements.

Re:Age of the universe.

[Anonymous Coward]

I don't understand why we have to have the religion debate every time an article mentions a date more than 6000 years in the past.

Because where I live, the majority of people actually believe in creationism, so an article claiming something is billions of years old doesn't make much sense.

Yes, I wish we didn't have to bring it up, but sadly, it's not off topic.

Re:Heavy elements?

[radurusu]

This is likely a 2nd or 3rd generation star. The heavy elements likely came from a short-lived (and larger) nearby star that went nova/supernova and seeded the region around it with heavy elements. Probably the shock wave from the supernova was the very thing that triggered star formation in the nearby hydrogen cloud.

Large stars burn out much more quickly than stars like Sol. Though none of them last long enough for intelligent life to develop in their solar system, they are essential to life in the universe--without them there would be no elements heavier than lithium.

Re:Heavy elements?

[Agent Orange]

That's correct. The star is metal-poor -- it's has an iron abundance (the standard measure of how much metals a star has) of [Fe/H] = -2.95. This is a lograthmic scale, and means that, on a scale where the sun is 0.0, HE1523 has about 1/1000th the amount of iron. The bracket notation means [Fe/H] = log10{N(Fe}/N(H)} - log10{N(Fe)/N(H)}_sun...i.e. the logarithmic difference of the number of atoms of Fe, compared to hydrogen, normalised to the solar ratio.

But the kicker is that HE1523 is very heavily r-process enhanced too...which means that it has a lot r-process, neutron-capture elements (think Uranium and thorium), compared to how much iron it has. HE1523 has [r/Fe] = 1.8....which means it has a 100 times more r-process heavy metals compared to iron, than does the sun.

BOTH of these factors are very important for this measurement, because you need to have very few metals, very high signal-to-noise data, very high resolution, and very strong r-process abundance, in order to be able to observe the uranium line. Anna needed 7.5hrs of VLT time to get a signal-to-noise ratio of about 350 or so...much higher than the S/N ~ 50-75 that we got from Magellan.

You can get a pdf of the paper here [arxiv.org]. Check out Fig 2, which shows the relevant part of the spectrum, with the Uranium line. See how it's right next to the booming Fe line...that's why we need a low iron abundance to do this work.

Creation of the elements -- nucleosynthesis primer

[Agent Orange]

There is a little confusion about how the elements are created, and where HE1523 got all it's metals from...so here is a quick primer on the way things work.

The big bang forms hydrogen, dueterium, some helium, and a tiny amount of lithium. In fact, the theory of what should be formed (called Big Bang Nucleosynthesis), and what is observed, agree incredibly well.

Most stars just burn hydrogen into helium, fusing the two hydrogen atoms. More massive stars burn hotter, and so they can ignite helium burning, forming carbon, nitrogen, oxygen etc. The hotter the star gets, the heavier things can be fused, all the way up to iron. All of these processes *release* energy, if you can get it hot enough to start the reaction.

After iron, to make heavier elements you have to *put in* energy, so the way elements are formed is different. Instead of fusing two things together, you now just add a single neutron to the nucleus. This is a very different process (called neutron capture)...and can happen veeeery slowly (in stars) or very rapidly (in supernova explosions).

So, uranium and thorium are both elements which are made in the rapid process (r-process) -- they are only made in supernova explosions...because in a supernova, the neutron density is very high, so catching one is more likely.

Anyway...the point of all this is that, by observing uranium, we KNOW there had to have been at least one dying star going supernova, which made the uranium. Then that gas collapsed again later, to make anna's star.

So far, no-one has yet managed to find a first-generation star, but it's a big area of research at the moment, and is one of the things anna is trying hard to find. By looking at these very old stars, we get a good picture of how a supernova works, because we see the product of ONLY ONE of them. With young stars, there might have been hundreds, all polluting the gas at different times...and disentangling that is really tough.

As for the age of the universe, WMAP [nasa.gov] told us that very precisely -- 13.7Gyr (with an error of only ~0.1Gyr). The age we derived from HE1523 is much less precise...but nucleocosmochronometry (stellar age dating), is an incredibly tough thing to do, but it does offer independant confirmationg of the WMAP result.

Re:Don't take those Pastors & Darwins either..

[Anonymous Coward]

It's appalling how many people think Darwin's theory implies we (humans) evolved from apes. The actual theory is rather that humans and apes share a common ancestor, and so if you go back far enough, we were once a single species. Owing to variation within that species, however, it gradually split in two, by way of natural and sexual selection, with one branch evolving into apes whilst the other evolved into humans (and other, now extinct, branches).

Re:Don't take those Pastors & Darwins either..

[mano_k]

It's appalling how many people think Darwin's theory implies we (humans) evolved from apes.

What is your problem with humans evolving from apes?
Of course we did not evolve from modern apes but from creatures who we, if we met them today, would probably call apes. And we share common ancestors with every known creature.

Btw. zoologically speaking we are apes!