Research publications: Recent submissions
Now showing items 7401-7420 of 9764
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The latitude distribution of star-spots on He 699
(2002-04-11)In this paper, the latitude distribution of star-spots is analysed for the rapidly rotating G dwarf He 699, An image has been reconstructed from data taken with the William Herschel Telescope on La Palma on 2000 October ... -
Doppler images from dual-site observations of southern rapidly rotating stars - II. Starspot patterns and differential rotation on Speedy Mic
(2001-06-11)We have secured high spatial and temporal resolution spectra of the rapidly rotating K dwarf Speedy Mic (HD 197890) at two sites and a common epoch of observations. The 0.38-d axial rotation period and the V-band magnitude ... -
Further images of α Persei G dwarfs
(2001-09-21)We present two images of intermediate and low axial inclination G dwarfs (AP 149 and AP 193) in the young open cluster a Persei, and compare these with previous images of intermediate and high axial inclination objects in ... -
Starspot patterns on the M dwarfs HK Aqr and RE 1816+541
(2001-09-21)We present the first Doppler images of two M dwarfs in the solar neighbourhood. Late-type dwarfs are generally too faint to enable spectra with sufficient signal-to-noise (SIN) ratios for Doppler imaging to be obtained in ... -
Doppler images from dual-site observations of southern rapidly rotating stars - I. Differential rotation on PZ Tel
(2000-05-01)We present Doppler images of the young, late-type star PZ Tel from spectroscopic observations at two epochs. The 0.95-d period necessitated dual-site observations in order to obtain full phase coverage. The resulting maximum ... -
Comparisons of images derived from independent Zeeman Doppler imaging codes
(2000-11-11)We compare surface brightness and magnetic field surface maps for the K0 dwarf AB Doradus, obtained using two independently developed Zeeman Doppler imaging codes. We find that even the fine structure in the two sets of ... -
The potential magnetic field of AB Doradus: comparison with Zeeman-Doppler images
(1999-05-01)We have modelled the global-magnetic-field topology of the young, rapidly rotating KO dwarf AB Dor by assuming that the field is potential and using as a boundary condition Zeeman-Doppler images of the surface radial field ... -
Latitude distributions and lifetimes of star-spots on G dwarfs in the alpha Persei cluster
(1998-09-21)We present a set of maximum-entropy reconstructions of the star-spot distributions on two rapidly rotating G dwarfs in the alpha Persei cluster, from spectra taken at the William Herschel Telescope on three nights in 1996 ... -
Chemodynamical simulations of the Milky Way Galaxy
(Cambridge University Press, 2009)We simulate the chemodynamical evolution of the Milky Way Galaxy, including the nucleosynthesis yields of hypernovae and a new progenitor model for Type la Supernovae (SNe la). In our nucleosynthesis yields of core-collapse ... -
The boundaries of Doppler imaging: Starspot patterns on M dwarfs
(2002)With the advent of 8-m class telescopes and model atmospheres incorporating molecular opacities a great deal of interest has been directed towards the previously unexplored cool, low mass stars. M dwarfs are obviously a ... -
Metallicity distributions of elliptical galaxies and globular cluster systems - Absorption line strength gradients in elliptical galaxies
(1999)Gradients of absorption line indices are studied and mean stellar metallicities are estimated for 46 elliptical galaxies. The mean stellar metallicities range from [[Fe/H]] similar or equal to -0.8 to +0.2 and ellipticals ... -
Supernova nucleosynthesis, chemical evolution, and cosmic supernova rate
(1999)In the chemical evolution of the Galaxy, Type II supernovae (SNe II) have contributed to the early metal enrichment and later Type Ia supernovae (SNe Ia) have contributed to the delayed enrichment of Fe. In principle, ... -
Chemo-dynamical Simulations and Galactic Archaeology
(American Institute of Physics (AIP), 2010)We predict the frequency distribution of elemental abundance ratios from Carbon to Zinc as a functions of time and location, which can be directly compared with the next generation of the galactic archeology project such ... -
Type Ia supernovae and chemical evolution of galaxies
(Wolters Kluwer, 2002)The cosmic/galactic chemical evolutions have been modeled with the early metal enrichment by Type II supernovae (SNe II) and the delayed enrichment of Fe by Type Ia supernovae (SNe Ia). However, the exact nature of SN Ia ... -
Dense spot coverage and polar caps on SV Cam
(European Space Agency (ESA), 2005)We have used spectrophotometric data from 9 HST orbits to eclipse-map the primary component of the RS CVn binary SV Cam. From these observations and SV Cam's HIPPARCOS parallax we find that the surface flux in the eclipsed ... -
The decrease in differential rotation with decreasing stellar mass in a sample of young rapidly rotating main sequence stars
(European Space Agency (ESA), 2005)In the Sun, global fluid circulation generates the large-scale magnetic field through cyclic dynamo action. Shear at the solar core/convection zone interface ensures that the convection zone does not rotate as a solid body. ... -
Cosmic supernova rate history and Type Ia supernova progenitors
(World Scientific Publishing, 2001)Adopting a single degenerate scenario for Type Ia supernova progenitors with the metallicity effect, we make a prediction of the cosmic supernova rate history as a composite of the supernova rates in spiral and elliptical ... -
Metallicity effect on type Ia supernovae and galactic and cosmic chemical evolution
(Springer Nature, 2000) -
Stellar chronology with white dwarfs in wide binaries
(Cambridge University Press, 2009)White dwarfs are the evolutionary end product of stars with low and intermediate masses. The evolution of white dwarfs can be understood as a cooling process, which is relatively well known at the moment;. For this reason, ...