BD 17° 3248

BD 17 ° 3248 is an old Population II stars in the halo of the Milky Way. It belongs to the rare class of ultra- metal - poor stars ( metallicity [Fe / H] = -2.1 ), and in turn to the rare subclass with an overabundance of r-process elements.

Detailed high-resolution spectroscopic studies were carried out ( with Chris Sneden of the University of Texas at Austin as the leading observers) on three large-scale equipment since 2000:

A) the Hubble Space Telescope (NASA / ESA Hubble Space Telescope )

B ) the Keck I Telescope in Hawaii and

C ) the H. J. Smith Telescope at the McDonald Observatory of the University of Texas.

The interaction of these telescopes allowed the determination of the frequencies of elements in this constellation over a wide range: from germanium (Z = 32 ) through uranium (Z = 92). With the space-based Hubble Telescope and spectra in the ultraviolet rays could be taken, which are absorbed by the Earth's atmosphere. This could also be the heavy metals osmium, platinum, and are first determined in an ultra - metal - poor star gold. The detection of the radioactive thorium and uranium metals ( only the second detection in such a star by CS31082 -001) allowed by comparison with one another and with a reliable stable elements dating.

All abundances for elements heavier than barium ( Z = 56 ) show the pattern of the elements formed by the r-process in the solar system. By comparing the observed in the star abundances of a stable element such as europium (Z = 63) and the radioactive elements thorium (Z = 90) and uranium (Z = 92) with calculated abundances of these elements in a type II supernova explosion (as of were carried out to groups of Karl -Ludwig Kratz in Mainz and Friedrich -Karl Thielemann in Basel) gives an age of about 13.8 billion years ( with an uncertainty of 4 billion years ) for this star, which thus only slightly later than the Big Bang was. Corresponding age determined for other ultra - metal - poor stars as CS22892 -052 or CS31082 -001. The agreement of the abundances of the elements formed in the r-process heavier than Ba in the very old stars in the solar system means that this Nukleosyntheseprozess runs on the same principle since the beginning.