Uncovering the chemical signatures of the first star clusters in the universe
by
Torgny Karlsson(Sydney)
→
Europe/Stockholm
FA31
FA31
Description
The oldest metal-poor stars are the lingering remains of a fiery
cosmic era. Their chemical abundance patterns are expected to
contain residual signatures of the earliest epoch of star and
galaxy formation. Today, essentially all stars are born in highly
homogeneous star clusters and it is likely that this was true also
at early times. If so, stars would exhibit a high degree of
clumping in abundance planes (i.e., C-space), such as [Ca/Fe] vs.
[Fe/H]. I will present new results where we show that these clumps
may, for certain chemical elements, be identified even in relatively
small data samples. Furthermore, the overall star-to-star scatter
in C-space can be much less than what is expected from earlier
chemical evolution models, in line with observations of extremely
metal-poor Galactic halo stars. Since stellar abundances may be
modified by mass transfer in close binaries, I will argue that
clustered signatures are essential for deriving the yields of the
first supernovae. Finally, I will discuss the HERMES project, seeking
to reconstruct the ancient Galactic disk and halo.