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Ancient star nearly as old as the Universe

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17 years 2 months ago #45844 by eansbro
An ancient star slightly smaller than the Sun blazed into life in our galaxy, formed from the newly scattered remains of the first stars in the universe.

Astronomers have learned that a metal-poor star called HE 1523 is 13.2 billion years old-just slightly younger than 13.7 billion year age of the universe.

The findings are detailed in the May 10 issue of Astrophysical Journal.

www.space.com/scienceastronomy/070510_oldest_star.html

Eamonn A

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17 years 2 months ago #45851 by albertw

Albert White MSc FRAS
Chairperson, International Dark Sky Association - Irish Section
www.darksky.ie/

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17 years 2 months ago #45852 by Mike
Replied by Mike on topic Oldest Stars
Eamonn, Al, thanks for the info!
Very interesting indeed, what was even more interesting was the following statement by Frebel…

“While HE 1523 certainly ranks among the oldest stars in the Milky Way, it probably is not the oldest.”This star has a certain metallicity by which we measure its chemical primitiveness, but there are other stars out there that are even more primitive in their nature”.

Does this mean we will eventually push the generally accepted 13.7 Billion year limit further out as even older stars (if they exist) are discovered?
For anyone that is interested here is an excellent all round presentation in PDF format entitled “The Oldest Stars in Our Galaxy” by Anna Frebel.
www.as.utexas.edu/astronomy/education/sp...secure/lecture23.pdf

Clear skies
Mike

I83 Cherryvalley Observatory

After one look at this planet any visitor from outer space would say; "I WANT TO SEE THE MANAGER".

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17 years 2 months ago #45854 by albertw
Replied by albertw on topic Re: Oldest Stars

Does this mean we will eventually push the generally accepted 13.7 Billion year limit further out as even older stars (if they exist) are discovered?


Well if we find older stars then something will have to change!

The 'live fast die young' stellar process is the problem here though. Big bright stars are easier to study but these early stars will have gone supernova early on.

To find the most metal free stars we need to look for stars that have been around for 13-14 billion years. And that leaves us with just small dim stars, in the order of half a solar mass. Older stars are probably out there but detecting them, and then getting the spectral analysis to say anything about them is difficult. The analysis of this took 7.5 hours of observing on the VLT for example.

Whether any population III stars, the original stars made from just hydrogen clouds, will ever be found is another question.

Albert White MSc FRAS
Chairperson, International Dark Sky Association - Irish Section
www.darksky.ie/

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