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Spying on the oldest stars in the Universe

Astronomers find a star that's 13.2 billion years old

read the story here

Posted by Katharine Sanderson on May 11, 2007
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I have reservations about this story.

Frebel says that he used abundances of uranium [4.5 billion year half-life] and thorium [14 billion year half life] to estimate the age of this "oldest star".

About half (1/2) of the thorium and seven-eights (7/8) of the uranium would have decayed away in 13.2 billion years. The thorium/uranium ratio now should be (1/2)/(1/8) = four (4) times the Th/U production ratio from rapid neutron capture.

What value was observed for the Th/U ratio in this oldest star? Is the Th/U ratio in this oldest star more than twice (>2) the Th/U ratio in the Sun?

As I recall it has been very difficult to measure the Th/U ratio in the Sun. I would expect very large error limits on the Th/U ratio in this oldest star.

With kind regards,
Oliver K. Manuel
www.omatumr.com


Posted by: Oliver K. Manuel | May 12, 2007 07:52 PM

i think i probably did not read the story carefully enough and my previous comment should not be published!

Posted by: Caroline Webb | May 15, 2007 07:44 PM

How can a star so old, and thus so near the start of the universe (if not before, thanks to the error bars) have had the heavy metals that were used to date it? To have uranium, it would have to be a third-generation star, right? Did the first stars form and burn out THAT fast?

Posted by: David Bump | May 16, 2007 03:25 AM

Greetings,

Many talented scientists invested a lot of time and effort in the study of old stars but the more I read, the more concerned I am that so many of the observations might be explained by a simple mass fractionation process that enriched the abundances of lighter weight atoms relative to heavier ones at the surfaces of these stars.

The observation of low [Fe/H], high [C/Fe], and low [U/Th] might mean very old, hydrogen-rich stars.

Or these same observations might mean that a mass fractionation process enriched the abundances of lightweight atoms relative to heavier ones at the surfaces of these stars.

My research mentor, Professor [Paul] Kazuo Kuroda, taught us not to criticize the work of others. I will ask the authors to respond here to the possible role of mass fractionation in producing their observations:

1. Material at the surface of stars may indicate their internal composition, as the authors assumed in using metal-poor stars (low [Fe/H]) to study the early universe.

OR

2. The element ratios at the surface of the Sun and other stars may depend on the magnetic fields that cause stars to act as magnetic plasma diffusers, selectively moving lightweight elements like H and He and lighter isotopes of each element to the surface.

http://www.omatumr.com/abstracts2005/The_Suns_Origin.pdf
or http://tinyurl.com/3ydcql

With kind regards,
Oliver K. Manuel
http://www.omatumr.com

Posted by: Oliver K. Manuel | May 21, 2007 01:40 AM

Greetings,

I sent Dr. Anna Frebel and each of her co-authors the following message. I will ask permission to post their replies here. - Oliver

Are H-rich stars old, or just more severely mass fractionated?

Dear Dr. _ _ _ _ _ _,

I am a nuclear chemist, a student of the late [Paul] Kazuo Kuroda, with very limited knowledge of astronomy.

Could the observations that form the basis of your recent papers on old, H-rich stars be explained by another interpretation?

1. H-rich material at the surface of stars may indicate that the interior of these stars is metal-poor (low [Fe/H]) material from the early universe.

OR

2. Other stars may, like the Sun, operate as magnetic plasma diffusers that selectively move lightweight elements like H and He and lighter isotopes of each element to their surfaces.

http://www.omatumr.com/abstracts2005/The_Suns_Origin.pdf
or http://tinyurl.com/3ydcql

In other words, low [Fe/H] ratios may indicate strong surface magnetic fields and an efficiently operating diffuser.

Which of your observations could not be explained by mechanism #2?

Thank you for your assistance.

With kind regards,
Oliver K. Manuel
http://www.omatumr.com


Posted by: Oliver K. Manuel | May 21, 2007 08:29 PM

A star 13.2 billion years old, rich in heavy elements specially uranium, must have been atleast a 2nd. generation star. I wonder did it originate from a galaxy of massive stars

Posted by: sunderajan | May 21, 2007 11:00 PM

I would think that since this star is so rich in metal, it quite possibbly has a planet orbiting.

Posted by: sunderajan | May 26, 2007 02:57 AM

Greetings,

I asked Dr. Anna Frebel about her measurements of the Th/U ratios in the Sun and in stars with H-rich surfaces.

She did not reply, but a co-author reminded me that it is difficult to measure this ratio from the solar spectrum because the Th and U absorption features are contaminated by other spectral lines.

The Th/U ratio in meteorites is assumed to be that in the Sun.

So the age estimate by Frebel et al. is based on a comparison of the Th/U ratio in meteorites with that observed at the surfaces of H-rich stars.

With kind regards,
Oliver K. Manuel
www.omatumr.com

Posted by: Oliver K. Manuel | June 1, 2007 09:11 PM

Greetings:

Hilton Ratcliffe's new book, "THE VIRTUE OF HERESY: Confessions of a Dissident Astronomer", will be a delight to those who are seriously interested in the mysteries of our universe -- old stars and young ones alike.

This is a bombshell for the smug community of scientists who have insisted that our infinitely beautiful universe is properly described by their standard mathematical models of a finite one.

Hilton is a great storyteller.

Curious minds of all ages will thrill to his telling of a journey through the real universe.

This is science unplugged, without the magical thinking and mathematical models that have mystified our heavens and isolated us from our own exciting universe.

I purchased this 400-page paperback book from the publisher for only $15.20 plus shipping. It is also available from several bookstores,

With kind regards,
Oliver K. Manuel
www.omatumr.com

Posted by: Oliver K. Manuel | July 22, 2007 11:02 PM

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