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A billion years after the big bang, hydrogen atoms were mysteriously torn apart into a soup of ions. Credit: NASA/ESA/A. Felid (STScI)).

Nearby Ancient Star is Almost as Old as the Universe

23 Feb , 2013

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A metal-poor star located merely 190 light-years from the Sun is 14.46+-0.80 billion years old, which implies that the star is nearly as old as the Universe!  Those results emerged from a new study led by Howard Bond.  Such metal-poor stars are (super) important to astronomers because they set an independent lower limit for the age of the Universe, which can be used to corroborate age estimates inferred by other means.

In the past, analyses of globular clusters and the Hubble constant (expansion rate of the Universe) yielded vastly different ages for the Universe, and were offset by billions of years! Hence the importance of the star (designated HD 140283) studied by Bond and his coauthors.

“Within the errors, the age of HD 140283 does not conflict with the age of the Universe, 13.77 ± 0.06 billion years, based on the microwave background and Hubble constant, but it must have formed soon after the big bang.” the team noted.

Metal-poor stars can be used to constrain the age of the Universe because metal-content is typically a proxy for age. Heavier metals are generally formed in supernova explosions, which pollute the surrounding interstellar medium. Stars subsequently born from that medium are more enriched with metals than their predecessors, with each successive generation becoming increasingly enriched.  Indeed, HD 140283 exhibits less than 1% the iron content of the Sun, which provides an indication of its sizable age.

HD 140283 had been used previously to constrain the age of the Universe, but uncertainties tied to its estimated distance (at that time) made the age determination somewhat imprecise.  The team therefore decided to obtain a new and improved distance for HD 140283 using the Hubble Space Telescope (HST), namely via the trigonometric parallax approach. The distance uncertainty for HD 140283 was significantly reduced by comparison to existing estimates, thus resulting in a more precise age estimate for the star.

Age estimate for HD 140283 is 14.46+-0.80 Gyr.  On the y-axis is the star's pseudo-luminosity, on the x-axis its temperature.  An evolutionary track was applied to infer the age (credit: adapted by D. Majaess from Fig 1 in Bond et al. 2013, arXiv).

HD 140283 is estimated to be 14.46+-0.80 billion years old. On the y-axis is the star’s pseudo-luminosity, on the x-axis its temperature. Computed evolutionary tracks (solid lines ranging from 13.4 to 14.4 billion years) were applied to infer the age (image credit: adapted from Fig 1 in Bond et al. 2013 by D. Majaess, arXiv).

The team applied the latest evolutionary tracks (basically, computer models that trace a star’s luminosity and temperature evolution as a function of time) to HD 140283 and derived an age of 14.46+-0.80 billion years (see figure above).  Yet the associated uncertainty could be further mitigated by increasing the sample size of (very) metal-poor stars with precise distances, in concert with the unending task of improving computer models employed to delineate a star’s evolutionary track.  An average computed from that sample would provide a firm lower-limit for the age of the Universe.  The reliability of the age determined is likewise contingent on accurately determining the sample’s metal content.  However, we may not have to wait long, as Don VandenBerg (UVic) kindly relayed to Universe Today to expect, “an expanded article on HD 140283, and the other [similar] targets for which we have improved parallaxes [distances].”

As noted at the outset, analyses of globular clusters and the Hubble constant yielded vastly different ages for the Universe.  Hence the motivation for the Bond et al. 2013 study, which aimed to determine an age for the metal-poor star HD 140283 that could be compared with existing age estimates for the Universe.  The discrepant ages stemmed partly from uncertainties in the cosmic distance scale, as the determination of the Hubble constant relied on establishing (accurate) distances to galaxies.  Historical estimates for the Hubble constant ranged from 50-100 km/s/Mpc, which defines an age spread for the Universe of ~10 billion years.

Age estimates for globular clusters were previously larger than that inferred for the Age of the Universe from the Hubble constant (NASA, R. Gilliland (STScI), D. Malin (AAO))

Age estimates for the Universe as inferred from globular clusters and the Hubble constant were previously in significant disagreement (image credit: NASA, R. Gilliland (STScI), D. Malin (AAO)).

The aforementioned spread in Hubble constant estimates was certainly unsatisfactory, and astronomers recognized that reliable results were needed.  One of the key objectives envisioned for HST was to reduce uncertainties associated with the Hubble constant to <10%, thus providing an improved estimate for the age of the Universe. Present estimates for the Hubble constant, as tied to HST data, appear to span a smaller range (64-75 km/s/Mpc), with the mean implying an age near ~14 billion years.

Determining a reliable age for stars in globular clusters is likewise contingent on the availability of a reliable distance, and the team notes that “it is still unclear whether or not globular cluster ages are compatible with the age of the Universe [predicted from the Hubble constant and other means].” Globular clusters set a lower limit to the age of the Universe, and their age should be smaller than that inferred from the Hubble constant (& cosmological parameters).

In sum, the study reaffirms that there are old stars roaming the solar neighborhood which can be used to constrain the age of the Universe (~14 billion years). The Sun, by comparison, is ~4.5 billion years old.

The team’s findings will appear in the Astrophysical Journal Letters, and a preprint is available on arXiv.  The coauthors on the study are E. Nelan, D. VandenBerg, G. Schaefer, and D. Harmer.  The interested reader desiring complete information will find the following works pertinent: Pont et al. 1998, VandenBerg 2000, Freedman & Madore (2010), Tammann & Reindl 2012.

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capitane Haddock
Guest
February 23, 2013 6:33 PM

Please help me out. I do see a conflict in this sentence:”age inferred for the star (14.46+-0.80 billion years) does not conflict with the latest estimates (2013) for the age of the Universe stemming from WMAP’s survey of the cosmic microwave background, which implies an age of 13.74+-0.11 billion years”.
So what is the real non conflicting age?

Stéphan Gaumont-Guay
Guest
Stéphan Gaumont-Guay
February 23, 2013 6:54 PM

Taking into account the uncertainty if each number, there is no conflict. When the ranges of two values overlap, they are said to be consistent.

Jamie Brightmore
Guest
February 23, 2013 7:08 PM

I don’t understand this either. Even if the age of the universe is uncertain, how can the (uncertain age) star be older?

Philip Wilson
Guest
February 23, 2013 7:42 PM

It can’t be and it isn’t. See Stephan’s comment and re-look at the error bars for the two independent methods of age determination. The WMAP estimate of the universe’s age has the smaller error bars.

Peter
Member
Peter
February 23, 2013 11:47 PM

Addendum: if you estimate one number to be 10 plus/minus two and another estimate puts it at 8 plus/minus 1.6 then the answers are consistent because there is commonality among the estimates. (8 to 9.6)You can estimate something to be older than the universe as long as the minus takes it back within agreed parameters.

Olaf
Member
Olaf
February 23, 2013 10:09 PM

Oldest possible age of the Universe 13.74+0.11 = 13.85 billion years.
Youngest possible age of the star 14.46-0.8 billion years =13.66 billion years.
The star could have formed 0.19 billion “years” after the big bang.

Lawrence B. Crowell
Member
Lawrence B. Crowell
February 24, 2013 3:01 AM

Clearly the actual age of the star must be near the smaller value. This seems to put some bounds on cosmic time scales. This star has low metallicity, but it must have enough to be main sequence. The question is whether it comes from the remains of ancient PopIII stars. This star must have enough elements heavier than hydrogen to be opaque and exist as a main sequence or PopII star.

LC

WisdomSpirit
Member
WisdomSpirit
February 24, 2013 12:24 AM

Damn, I was thinking the same thing when I 1st read the headline on this topic. Then I thought about a black hole picking up a star in its gravity. The more we find out things, the more it adds and harbors more questions. Speculations galore!

Zaoldyeck
Guest
Zaoldyeck
February 24, 2013 4:19 AM

UNCERTAINTY!!! Notice those “+/-” signs? They’re not there for show, they are there to give you a measurement of error. The fact that the two ranges overlap without even going two standard deviations away, there is no statistical difference between the age given by this star, and the age given by WMAP.

Richard Kirk
Member
Richard Kirk
February 24, 2013 11:19 AM
I think I can see the problem people are having with this result. It isn’t just about error bars – it’s more how could a model that predicts the age based on the evolution of metals from the ancient and short-lived pop III stars shortly after the Big Bang predict a date Before This Process Even Started? I, myself, did have a short WTF moment. But, there is a logical explanation… Before there were stars, there was hydrogen, some deuterium, maybe a tiny amount of helium, and very little else. So that would normally be our time zero point. It is possible that there are pockets of that primordial gas surviving today. If it were all rolled into… Read more »
Torbjorn Larsson OM
Member
Torbjorn Larsson OM
February 24, 2013 2:57 PM

“how could a model that predicts the age based on the evolution of metals from the ancient and short-lived pop III stars shortly after the Big Bang predict a date Before This Process Even Started”.

Simply by having those being two independent observations.

That is also why the overlap, the absence of difference, is so extraordinary neat!

Mike Petersen
Guest
Mike Petersen
February 23, 2013 8:51 PM

Hmm…maybe this star is the Universe’s daddy. hehehe

M Peter Selman
Guest
February 23, 2013 10:19 PM

Yes! I wondered if one would ever be found!

Nexus
Member
February 23, 2013 10:39 PM

So this star was born before the Galaxy even existed. That’s cool.

Zaoldyeck
Guest
Zaoldyeck
February 24, 2013 4:20 AM

It would be if they had better than a .8GyR uncertainty. I’d bet quite a lot that as they tighten their uncertainty, they’ll get an age closer to WMAP’s data.

mmurdoch
Guest
mmurdoch
February 24, 2013 1:06 AM

It’s also pretty amazing that anything 190 light years away could be ranged by parallax.

Aqua4U
Member
February 24, 2013 2:22 AM

The accompanying link mentions that the fine guidance sensors on the Hubble Space Telescope were used in conjunction with Hipparchus data to determine accurate parallax distances.

Zaoldyeck
Guest
Zaoldyeck
February 24, 2013 3:55 AM

God bless arxiv.

SteveZodiac
Member
SteveZodiac
February 24, 2013 8:37 AM

It’s almost 60 parsecs – since 1 parsec is one arc second angle and we have two AUs to play with (without doing the trig) it’s probably a manageable fraction of an arc second. If you have Celestia you can pick a nearby star and wind time up so fast you can see it wobble from the parallax shift.

Mark Finnigan
Guest
Mark Finnigan
February 23, 2013 8:52 PM

Unless I missed it, I am assuming this is likely a red dwarf to be that old. It would be interesting to find out if there are any planets orbiting it. That would certainly put a kink in a few theories about whether planets could for around such metal poor stars.

Just thinking out loud.

Aqua4U
Member
February 24, 2013 2:15 AM

Very interesting! At 7th magnitude, this star should be visible in many amateur astronomer’s telescopes @ 15h 43m 03.1′, -10*56’01” (Libra) and would make for an interesting star party object! Unfortunately(?) at this time of year, rising in the wee late or early morning hours.. Maybe someone can take a shot and post it during the Star Party?

Kevin Frushour
Guest
February 24, 2013 3:19 AM

Astronomers discovered it when the star yelled at The Sun to get off its lawn.

John Hyatt
Guest
John Hyatt
February 27, 2013 5:28 AM

You a funny boy…

kyle evans
Guest
February 24, 2013 4:21 AM

sorry science people but it’s pretty hard for this star to be that old when god created the universe 6000 years ago.

Duane B
Guest
February 24, 2013 4:26 AM

0/10

Split Horizon
Guest
February 24, 2013 5:00 AM

LOL

mmurdoch
Guest
mmurdoch
February 24, 2013 5:24 AM

6000 *god* years. They’re longer.

Ezekial Shake
Guest
February 24, 2013 6:45 AM

it’s location in space would be all wrong if current theory is correct – perhaps our whole system of dating the “age” of the universe is off

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
February 24, 2013 2:47 PM

Why would its location be “all wrong”? The Milky Way started out at ~ 400 million years as all other galaxies, see the first image. It has to have the oldest stars, same as the other galaxies.

The Latinist
Guest
The Latinist
February 25, 2013 3:29 PM
Why do you say that? There’s no reason a small enough Pop II star from shortly after the big bang couldn’t survive and still be around today in our neighborhood. Remember that the big bang occurred everywhere (or, put another way, everywhere was once where the big bang occurred), so remnants of it could be found anywhere. And 14 Gyr isn’t so long for a red dwarf, say, to so exist. Perhaps you are thinking about the fact that to see things as they were shortly after the big bang we have to look far way. But nobody is claiming that we’re seeing this star as it was 14 Gya; they’re claiming that they are seeing a 14… Read more »
Jmaximus Spartacus
Guest
February 24, 2013 7:02 AM

Wait a minute here, last I checked the science said the Universe is 13.77 billion years old, that would make this star older than the Universe.

I'manidiot
Guest
I'manidiot
February 24, 2013 7:23 AM

not technically, the error on the estimate of the star’s age allows for the potential age of the star to be from 13.64 to 15.24 billion years. the age of the universe is 13.77+-.06. Meaning the star was either formed at t=0 in respect to the universe up to t = .19 billion years. Meaning yes this could be a really interesting star that could provide more obtainable data to piece together events in the beginning of the universe but it could also be a dud as a lot of shit happens in .19 billion years

Adam Astles
Guest
February 24, 2013 7:33 AM

I doubt that figure was written in stone never to be challenged to new information.

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
February 24, 2013 2:44 PM

Read the article:

“A metal-poor star located merely 190 light-years from the Sun is 14.46+-0.80 billion years old, which implies that the star is nearly as old as the Universe!”

““Within the errors, the age of HD 140283 does not conflict with the age of the Universe, 13.77 ± 0.06 billion years, based on the microwave background and Hubble constant, but it must have formed soon after the big bang.” the team noted.”

Error estimates are useful, but especially in these cases.

Adam Astles
Guest
February 24, 2013 7:38 AM

If there are any, I’d guess that they would probably be gas giants formed at the same time, or rogue planets that have been caught by the system’s gravity well.

Mark Finnigan
Guest
Mark Finnigan
February 24, 2013 5:48 PM

If there were terrestrial planets present, and they could be shown not to be rogues, what a story they could tell. The cratering alone would be treasure trove of the universes history.

Adam Astles
Guest
February 25, 2013 11:16 AM

Non rogue terrestrial planets would be mind blowing.

SteveZodiac
Member
SteveZodiac
February 24, 2013 8:24 AM

Good thought

Decapitated
Guest
February 24, 2013 9:41 AM

Unfortunately, despite its very old age, it’s still a Population II star. We’ve yet to discover any Population III stars, leaving them merely theoretical.

The Latinist
Guest
The Latinist
February 25, 2013 3:17 PM

We’re going to have to look a lot farther away than 190 ly to find a Population III star…

Nirmalendu Das
Guest
February 24, 2013 12:04 PM

The
age of the Sun nearly the age of the universe.

“A
metal-poor star located merely 190 light-years from the Sun is 14.46+-0.80
billion years old, which implies that the star is nearly as old as the
Universe! “

I calculate and written in my book “Complete Unified Theory”, (page-150-152,
total page-424, 1998), that the age of the Sun is 14.6156 billion years. So,
the sun is 0.1556 times older than the HD 140283 star. The birth of the sun is indicating
nearly the birth of the universe.

I want to request to all scientists in this fields, please verify the
age of the sun / universe again.

Nirmalendu Das.

Dated: 24-02-2013.

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
February 24, 2013 2:36 PM

Kudos for using the latest, most precise, age for the universe, even if it moved [gasp!] the age from ~ 13.7 years to ~ 13.8 years! What is +/- 60 million years among friends? I like how cosmology has become a precision science.

The oldest discovered planet to date should still bePSR B1620-26 b @ ~ 12.7 billion years. PSR B1620-26 metallicity is unknown, but it inhabits a low metallicity star cluster M4, with [Fe/H] ~ -1.20 [ http://arxiv.org/pdf/astro-ph/0409762.pdf ].

Naively, since frequency of terrestrials shows no correlation to metallicity, another order of magnitude (oom) lower metallicity shouldn’t be a problem. (Another oom, since [Fe/H] is a logarithmic measure.) These early stars could have planets!

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
February 24, 2013 2:51 PM

It is only gas giants that correlates with metallicity, see Kepler & Corot data, they are rarer in metal rich stars.* Terrestrials form independently of metallicity.

Maybe you are referring to pre-survey hypotheses?

* Apparently gas giants don’t have as much time to form by core collapse, if the core is formed as terrestrials by aggregation and they are equally frequent everywhere. Meaning the disk scatters faster around metal rich stars.)

ITSRUF
Guest
ITSRUF
February 24, 2013 8:52 PM

Could the star have formed later (ie. more recently) for a more “pristine” cloud of gas?

postman1
Member
postman1
February 25, 2013 1:14 AM

Maybe Torbjörn Larsson can answer this one, are they saying this star existed before the Milky Way and was drawn into it, or is the Milky Way possibly older than thought?

Steve WidHo
Guest
February 26, 2013 1:14 AM

After so many years stating that the Universe is 13.73 BYO, how can they now say a single star is 14.46 BYO? Is everybody using different parameters to date objects in the Universe? I thought it was one procedure agreed on decades ago that the entire Science used…..

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