Page 1 of 1

UTexas: Astronomers Find Sun’s ‘Long-Lost Brother’

Posted: Fri May 09, 2014 5:21 pm
by MargaritaMc
McDonald Observatory, University of Texas at Austin.

Astronomers Find Sun’s ‘Long-Lost Brother,’ Pave Way for Family Reunion
8 May 2014

AUSTIN — A team of researchers led by University of Texas at Austin astronomer Ivan Ramirez has identified the first “sibling” of the Sun — a star that was almost certainly born from the same cloud of gas and dust as our star. Ramirez’ methods will help other astronomers find other “solar siblings,” work that could lead to an understanding of how and where our Sun formed, and how our solar system became hospitable for life. The work will be published in the June 1 issue of The Astrophysical Journal.

http://mcdonaldobservatory.org/news/releases/2014/05/08
The research article is available to download here:
http://www.as.utexas.edu/~ivan/sun_siblings.pdf

Re: UTexas:Astronomers Find Sun’s ‘Long-Lost Brother.

Posted: Fri May 09, 2014 6:26 pm
by Ann
How fascinating! How thrilling! :D

I checked out HD 162826 with my software and was pleased to see that it is clearly bluer (and thus hotter) than the Sun, although not by all that much. Its B-V index is 0.541 ± 0.005, versus 0.656 ± 0.005 for the Sun. Also HD 162836 is brighter than the Sun, 2.253 ± 0.055 solar luminosities, according to my software. It is classified as a star of spectral class F8V. The distance to this star is 109 ± 1.3 light-years. That is of course utterly unimaginably far away, and yet, by galactic standards, it is right on our doorstep. We are lucky to have found a "solar brother" so close to our own solar system!
http://mcdonaldobservatory.org/news/releases/2014/05/08 wrote:
“The idea is that the Sun was born in a cluster with a thousand or a hundred thousand stars. This cluster, which formed more than 4.5 billion years ago, has since broken up,” he [Austin astronomer Ivan Ramirez] says.
A cluster with perhaps a hundred thousand stars??? :shock: Wow!!

Please check out this page, which contains some information (and some beautiful photos) of globular clusters M53 and NGC 5053. M53, a relatively rich cluster, is said to contain about 250,000 stars, whereas NGC 5053 is said to have "a much lower density of stars compared to M53. Perhaps there are fewer than 100,000 stars in NGC 5053? Note that the Pleiades, according to http://en.wikipedia.org/wiki/Pleiades#Composition, possibly only contains about a thousand stars (exluding members of binary stars, however). Our Sun might have been born in a bigger, richer cluster than the Pleiades! As you can hear I am duly impressed by the of our Sun's possibly splendidly brilliant and sparkling birthplace.

I note that HD 162826 is more massive than the Sun, but it has not yet begun to turn into a red giant. That's a relief, because it suggests that our own Sun's demise is a long way off. (Yes, I know, scientists have long predicted that fact, but it is nice to see it seemingly confirmed by the Sun's more massive "brother".)

But HD 162826 may not have any Jupiters. If not, it makes you wonder - or it makes me wonder - why not. Perhaps it was too close to one of the brilliantly blue and ultraviolet massive stars in in our Sun's and HD 162826's birth cluster, so that its protoplanetary disk was blown away by the hot star's radiation. Or perhaps HD 162826 interacted too closely with another cluster member and and had its massive planets swept away.

In any case, this is just so fascinating, Margarita! :D

Ann

Re: UTexas:Astronomers Find Sun’s ‘Long-Lost Brother.

Posted: Sat May 10, 2014 1:12 pm
by BDanielMayfield
Way to go, UT Astronomy!

January before last we (my wife and I) vacationed in west Texas and one of the highlights for both of us were the guided tours we took at McDonald Observatory. These tours took us up as close inside the workings of these scopes, as far as non professionals are allowed to be inside the Harlan J. Smith and the amazing Hobby-Eberly Telescope buildings. It is wonderful that the old workhorse scope was able to be used to make this important discovery.

If you’re ever in west Texas by all means take some time to visit McDonald Observatory. It is awesome!

Bruce

Re: UTexas:Astronomers Find Sun’s ‘Long-Lost Brother.

Posted: Sat May 10, 2014 7:46 pm
by MargaritaMc
It IS fascinating research, I'm pleased you both found it of interest.

I was intrigued by the name of the McDonald Observatory (and wondered if it was linked to hamburgers...) and found this website run by the observatory, which was actually dedicated 75 years ago. The site looks to be a very useful resource.
http://stardate.org/
StarDate is the public education and outreach arm of the University of Texas McDonald Observatory. Our radio program airs daily on almost 300 stations. And our popular bimonthly astronomy magazine is the perfect skywatching companion for anyone interested in astronomical events and space exploration. We also offer astronomy resources to teachers, the media, and the public.
Margarita

Re: UTexas:Astronomers Find Sun’s ‘Long-Lost Brother.

Posted: Sat May 10, 2014 9:52 pm
by Beyond
Three hours after posting my question, I realized that it was already answered, so i went to delete this post, but there's no delete button. What happened to it??
Anyway, when someone of importance sees this, please delete this remainder. Thank you.

Re: UTexas: Astronomers Find Sun's 'Long-Lost Brother'

Posted: Thu May 15, 2014 11:19 pm
by bystander
MargaritaMc wrote:
The research article is available to download here:
http://www.as.utexas.edu/~ivan/sun_siblings.pdf

Elemental Abundances of Solar Sibling Candidates - I. Ramirez et al