Tag Archives: stars

The Lithium problem. Primordial, cosmological or stellar?

We all have heard about it since kindergarden, but would you bet 5000 SEK you know exactly what it is? I did not, so had to look it up. And here is what I have learned.
First of all, let’s play it fair: there’s two stable lithium isotopes, lithium-six and lithium-seven. In the last years it seemed both had problems, but we are talking about the bigger brother here, the one who has had problems for a longer time. Since 1982, 30 years ago -when my brother was born- there have been observations of lithium-seven in metal poor stars of the galactic halo.

The end for supermassive population III stars?

Are the first stars really very massive? Some 10 years ago, the idea that the first, metal-free stars would be very massive, became popular. Simple theoretical arguments about radiative cooling and complex numerical simulations both seemed to point to the formation of metal-free stars of masses of several 100s solar masses. Because of their zero metallicity they were dubbed Pop III stars. Early simulations of their formation are commonly associated with Tom Abel and Volker Bromm.