PDA

View Full Version : Shedding Light on the Sun's "Lithium Mystery"



Fraser
2009-Nov-11, 08:50 PM
For decades, astronomers have known our Sun contains a low amount of lithium, while other solar-like stars actually have more. But they didn't know why. By looking at stars similar to the Sun to study this anomaly, scientists have now discovered of a trend: the majority of stars hosting planets possess [...]

More... (http://www.universetoday.com/2009/11/11/shedding-light-on-the-suns-lithium-mystery/)

trinitree88
2009-Nov-12, 02:32 PM
Fraser. Very interesting. Nice find. Thanks. :dance::clap:Pete

dhd40
2009-Nov-12, 05:10 PM
For decades, astronomers have known our Sun contains a low amount of lithium, while other solar-like stars actually have more. But they didn't know why. By looking at stars similar to the Sun to study this anomaly, scientists have now discovered of a trend: the majority of stars hosting planets possess [...]

More... (http://www.universetoday.com/2009/11/11/shedding-light-on-the-suns-lithium-mystery/)
Interesting, BUT


scientists have now discovered of a trend: the majority of stars hosting planets possess less than 1% of the amount of lithium shown by most of the other stars (my bold)
Trends arenīt proofs


This finding … also provides astronomers with a very efficient way of finding stars with planetary systems
Yes, thatīs a good point


These stars have been "very efficient at destroying the lithium they inherited at birth”
As long as the physical mechanism (see below) is unknown, I would hesitate to talk about destroying inheritated lithium. Maybe, the BB lithium never participated in the star forming process?

Now that a link between the presence of planets and curiously low levels of lithium has been established, the physical mechanism behind it has to be investigated (my bold)
Yes, because a link is not yet a proof.

galacsi
2009-Nov-12, 11:45 PM
So , not all stars , burn completely their Lithium. From a discussion about Brown dwarfs I believed stars ,first burned their lithium and deuterium , and only after that ,burned their hydrogen. But maybe it is only true in the core and not on the surface. I am very confused with this discovery.

Fortunate
2009-Nov-14, 11:37 PM
galacsi,
A star will only burn a fraction of its lithium. The temperature at the surface of the star is not high enough to destroy lithium, so unless a particular lithium nucleus moves deep within the star, it will remain intact. The following article suggests two mechanisms by which planetary systems around a star might cause enough turbulence within the star to pull the lithium down to where it will burn.
http://physicsworld.com/blog/2009/11/exoplanets_and_the_lithium_pro.html