Hayek, W., Wiesendahl, U., Christlieb, N., Eriksson, K., Korn, A. J., Barklem, P. S., ...
We report on a detailed abundance analysis of two strongly r-process enhanced, very metal-poor stars newly discovered in the HERES project, CS 29491-069 ([Fe/H]=-2.51, [r/Fe]=+1.1) and HE 1219-0312...
Korn, A. J., Richard, O., Mashonkina, L., Bessell, M. S., Frebel, A., Aoki, W.
Based on spectroscopic constraints derived from NLTE line formation, we explore the likely range of stellar parameters (T_eff and log g) for the hyper-metal-poor (HMP) star HE 1327-2326. Combining...
Lind, K., Korn, A. J., Barklem, P. S., Grundahl, F.
Evolutionary trends in the surface abundances of heavier elements have recently been identified in the globular cluster NGC 6397 ([Fe/H]=-2), indicating the operation of atomic diffusion in these...
A new sample of extremely/ultra metal-poor stars (2008)
Garcia Perez, A. E., Christlieb, N., Ryan, S. G., Beers, T. C., Aoki, W., Asplund, M., ...
Atomic Diffusion and Mixing in Old Stars I. VLT/FLAMES-UVES Observations of Stars in NGC 6397 (2007)
Korn, A. J., Grundahl, F., Richard, O., Barklem, P. S., Mashonkina, L., Collet, R., ...
We present a homogeneous photometric and spectroscopic analysis of 18 stars along the evolutionary sequence of the metal-poor globular cluster NGC 6397 ([Fe/H] = -2), from the main-sequence turnoff...
HE 0557-4840 - Ultra-Metal-Poor and Carbon-Rich (2007)
Norris, John E., Christlieb, N., Korn, A. J., Eriksson, K., Bessell, M. S., Beers, Timothy C., ...
We report the discovery and high-resolution, high S/N, spectroscopic analysis of the ultra-metal-poor red giant HE 0557-4840, which is the third most heavy-element deficient star currently known. Its...
New Abundances for Old Stars - Atomic Diffusion at Work in NGC 6397 (2006)
Korn, A. J., Grundahl, F., Richard, O., Barklem, P. S., Mashonkina, L., Collet, R., ...
A homogeneous spectroscopic analysis of unevolved and evolved stars in the metal-poor globular cluster NGC 6397 with FLAMES-UVES reveals systematic trends of stellar surface abundances that are...
A non-LTE study of neutral and singly-ionized calcium in late-type stars (2006)
Mashonkina, L., Korn, A. J., Przybilla, N.
Non-local thermodynamical equilibrium (NLTE) line formation for neutral and singly-ionized calcium is considered through a range of spectral types when the Ca abundance varies from the solar value...
A probable stellar solution to the cosmological lithium discrepancy (2006)
Korn, A. J., Grundahl, F., Richard, O., Barklem, P. S., Mashonkina, L., Collet, R., ...
The measurement of the cosmic microwave background has strongly constrained the cosmological parameters of the Universe. When the measured density of baryons (ordinary matter) is combined with...
VLT-FLAMES survey of massive stars (Evans+, 2005) (2006)
Evans, C.J., Smartt, S.J., Lee, J.K., Lennon, D.J., Kaufer, A., Dufton, P.L., ...
Astrometry and photometry for our target fields were acquired from observations for the ESO Imaging Survey (EIS) that used the Wide Field Imager (WFI) at the 2.2-m MPG/ESO telescope. The brightest...
Korn, A. J., Nieva, M. F., Daflon, S., Cunha, K.
We present spectroscopic abundance analyses of three main-sequence B stars in the young Large Magellanic Cloud cluster NGC 2004. All three targets have projected rotational velocities around 130...
The sensitivity of Lick indices to abundance variations (2005)
Korn, A. J., Maraston, C., Thomas, D.
We present results of model atmosphere/line formation calculations which quantitatively test how the 21 classical and four higher-order Balmer-line Lick/IDS indices (Worthey et al. 1994; Worthey &...
Evans, C. J., Smartt, S. J., Lennon, D. J., Kaufer, A., Dufton, P. L., ...
We introduce a new survey of massive stars in the Galaxy and the Magellanic Clouds using the Fibre Large Array Multi-Element Spectrograph (FLAMES) instrument at the Very Large Telescope (VLT). Here...
Christlieb, N., Beers, T. C., Barklem, P. S., Bessell, M., Hill, V., Holmberg, J., ...
We report on a dedicated effort to identify and study metal-poor stars strongly enhanced in r-process elements ([r/Fe] > 1 dex; hereafter r-II stars), the Hamburg/ESO R-process Enhanced Star survey...
Measurement of the Atmospheric Muon Spectrum from 20 to 3000 GeV (2004)
Achard, P, Adriani, O, Aguilar-Benítez, M, Van Den Ancker, M E, Alcaraz, J, Alemanni, G, ...
The absolute muon flux between 20 GeV and 300 GeV is measured with the L3 magnetic muon spectrometer for zenith angles ranging from 0 degree to 58 degrees. Due to the large exposure of about 150 m2...
Christlieb, N., Beers, T. C., Barklem, P. S., Bessell, M., Hill, V., Holmberg, J., ...
We report on a dedicated effort to identify and study metal-poor stars strongly enhanced in r-process elements ([r/Fe]>1 dex; hereafter r-IIstars), the Hamburg/ESO R-process Enhanced Star survey...
HE0107-5240, A Chemically Ancient Star.I. A Detailed Abundance Analysis (2003)
Christlieb, N., Gustafsson, B., Korn, A. J., Barklem, P. S., Beers, T. C., Bessell, M. S., ...
We report a detailed abundance analysis for HE0107-5240, a halo giant with [Fe/H]_NLTE=-5.3. This star was discovered in the course of follow-up medium-resolution spectroscopy of extremely metal-poor...
Korn, A. J., Shi, J., Gehren, T.
Non-LTE line formation calculations of Fe I are performed for a small number of reference stars to investigate and quantify the efficiency of neutral hydrogen collisions. Using the atomic model that...
Pristine CNO abundances from Magellanic Cloud B stars I. The LMC cluster NGC 2004 with UVES (2002)
Korn, A. J., Keller, S. C., Kaufer, A., Langer, N., Przybilla, N., Stahl, O., ...
We present chemical abundances for four main sequence B stars in the young cluster NGC 2004 in the Large Magellanic Cloud (LMC). Apart from H II regions, unevolved OB-type stars are currently the...
Gehren, T., Korn, A. J., Shi, J.
NLTE line formation calculations of FeI in the solar atmosphere are extended to include weak optical lines. Previously established atomic models are used to discriminate between different ways of...