7 papers
FUSE Observations of the Post-AGB Star ZNG 1 in the Globular Cluster M5 (NGC 5904)
W. V. Dixon, T. M. Brown, W. B. Landsman
We have observed the hot post-AGB star ZNG 1 in the globular cluster M5 with the Far Ultraviolet Spectroscopic Explorer (FUSE). From the resulting spectrum, we derive an effective…
A New Formation Mechanism for the Hottest Horizontal-Branch Stars
Allen V. Sweigart, Thomas M. Brown, Thierry Lanz +2
Stars with very large mass loss on the red-giant branch can undergo the helium flash while descending the white-dwarf cooling curve. Under these conditions the flash convection zon…
The Origin of Hot Subluminous Horizontal-Branch Stars in Omega Centauri and NGC 2808
Allen V. Sweigart, Thomas M. Brown, Thierry Lanz +2
Hot subluminous stars lying up to 0.7 mag below the extreme horizontal branch (EHB) are found in the UV color-magnitude diagrams of omega Cen and NGC 2808. Such stars are unexplain…
Blue horizontal branch stars in metal-rich globular clusters. II. 47 Tuc and NGC 362
S. Moehler, W. B. Landsman, B. Dorman
Atmospheric parameters (effective temperature, surface gravity) and radial velocities are derived for 12 candidate blue horizontal branch (HB) stars in the globular clusters 47 Tuc…
Hot HB stars in globular clusters - Physical parameters and consequences for theory. V. Radiative levitation versus helium mixing
S. Moehler, A. V. Sweigart, W. B. Landsman +1
Atmospheric parameters (effective temperature Teff, surface gravity log g), masses and helium abundances are derived for 42 hot horizontal branch (HB) stars in the globular cluster…
Blue Horizontal--Branch Stars: The "Jump" in Stromgren u, Low Gravities, and Radiative Levitation of Metals
F. Grundahl, M. Catelan, W. B. Landsman +3
We study the ``jump'' in the blue horizontal--branch (BHB) distribution first detected by Grundahl et al. (1998) in the Galactic globular cluster (GC) M13. On the basis of Stromgre…