Search Publications
The local surface density of disc matter mapped by Hipparcos
Flynn, Chris; Holmberg, Johan
We determine the surface density of matter in the disc of the Galaxy at the solar position using K giant stars. The local space density and luminosity function of the giants is determined using parallaxes from the Hipparcos satellite; for more distant giants, observed in a cone at the South Galactic Pole, distances are determined using intermediat…
Lithium abundances of the local thin disc stars
Lambert, David L.; Reddy, Bacham E.
Lithium abundances are presented for a sample of 181 nearby F and G dwarfs with accurate Hipparcos parallaxes. The stars are on circular orbits about the Galactic centre and, hence, are identified as belonging to the thin disc. This sample is combined with two published surveys to provide a catalogue of lithium abundances, metallicities ([Fe/H]), …
Synthetic stellar populations: single stellar populations, stellar interior models and primordial protogalaxies
Jimenez, Raul; Dunlop, James S.; Peacock, John A. +2 more
We present a new set of stellar interior and synthesis models for predicting the integrated emission from stellar populations in star clusters and galaxies of arbitrary age and metallicity. This work differs from existing spectral synthesis codes in a number of important ways, namely (1) the incorporation of new stellar evolutionary tracks, with s…
Asteroseismology of the β Cephei star ν Eridani - III. Extended frequency analysis and mode identification
Handler, G.; De Ridder, J.; Heiter, U. +7 more
Using the large photometric and spectroscopic data sets of the ν Eridani multisite campaign given in our two recent papers (Aerts et al. and Handler et al.), we present an extended frequency analysis and a photometric mode identification. For the extended frequency analysis, we used an improved radial velocity time series, the second-moment time s…
Kinematics of stellar associations: the epicycle approximation and the convergent point method
Olling, Rob P.; Makarov, Valeri V.; Teuben, Peter J.
Employing analytical and numerical tools, we expound the Galactic epicycle theory to describe the kinematic evolution of stellar, gravitationally unbound associations in the vicinity of the Sun. We estimate the limits of applicability of the analytical epicycle approximation and harmonic vertical motion by numerical integration of test orbits with…
Continuous and burst-like accretion on to substellar companions in Mira winds
Struck, Curtis; Cohanim, Babak E.; Willson, Lee Anne
We present numerical hydrodynamical modelling of the effects of a giant planet or brown-dwarf companion orbiting within the extended atmosphere and wind formation zone of an approximately solar-mass Mira variable star. The large-scale, time-dependent accretion flows within the radially oscillating and outflowing circumstellar gas around Miras are …
Period-luminosity relation for M-type semiregular variables from Hipparcos parallaxes
Yeşilyaprak, C.; Aslan, Z.
We have studied the period-luminosity (P-L) relationships of oxygen-rich semiregular (SR) variables in several wavelength bands using Hipparcos parallaxes with an accuracy of better than 10 per cent. We have shown that there is a clear dependence on period of absolute magnitude in the U,B,V,R,IC,J,H,K,L,M,N, [12], [25], [60] and [100] b…
A spectral analysis of the periodicity hypothesis in cratering records
Yabushita, Shin
Analysis is made of cratering records, whereby not only the crater ages, but also the sizes can be naturally taken into account. The method adopted is the periodogram analysis first discussed by Lomb. From the crater data based on Grieve's compilation, a period can be derived when a statistical weight of a crater is taken proportional to the size …