On the opacity change required to compensate for the revised solar composition (2008)
Christensen-Dalsgaard, Jørgen, Di Mauro, Maria Pia, Houdek, Günter, Pijpers, Frank
Recent revisions of the determination of the solar composition have resulted in solar models in marked disagreement with helioseismic inferences. The effect of the composition change on the model is...
Hans Kjeldsen, Timothy R. Bedding, R. Paul Butler, Jørgen Christensen-dalsgaard, Laszlo L. Kiss, Chris Mccarthy, ...
We have made velocity observations of the star«Cen B from two sites, allowing us to identify 37 oscillation modes with l = 0–3. Fitting to these modes gives the large and small frequency...
Lebreton, Yveline, Montalbán, Josefina, Christensen-Dalsgaard, Jørgen, Roxburgh, Ian W., Weiss, Achim
Solar Models With Consistent Diffusion and Monochromatic Opacities (2007)
Sylvain Turcotte, Jørgen Christensen-Dalsgaard, Danmarks Grundforskningsfond
Introduction Standard solar models now include settling of helium and heavy elements. Some simplifying assumptions are made concerning the settling of heavy elements. The impact of these...
Stellar Evolution With a Variable Mixing-Length Parameter (2007)
Regner Trampedach, Robert F. Stein, Jørgen Christensen-Dalsgaard, Ake Nordlund
. By simulating the convection in the upper layers of seven different stars and matching these simulations to 1D mixing-length models using the same input physics, we have been able to infer the...
CONVECTIVE PERTURBATIONS TO SOLAR OSCILLATIONS: THE f MODE (2007)
Colin S. Rosenthal, Jørgen Christensen-Dalsgaard, Åke Nordlund, Regner Trampedach, Danmarks Grundforskningsfond
We describe a variational method for calculating the influence of convective velocity, density, and soundspeed fluctuations on the eigenfrequencies of solar oscillations, under the assumption that...
Modelling Solar-Like Oscillations in . . . (2007)
Jørgen Christensen-Dalsgaard, Teoretisk Astrofysik, Timothy R. Bedding, Hans Kjeldsen
Kjeldsen et al. (1995, AJ in press) recently obtained strong evidence for solar-like oscillations in the G0 IV star j Boo. Here we present evolution calculations for the star and compare them with...
Near-Surface Effects in Modelling Oscillations of . . . (2007)
Jørgen Christensen-Dalsgaard, Danmarks Grundforskningsfond, Timothy R. Bedding, Günter Houdek, Hans Kjeldsen, Colin Rosenthal, ...
-pressure perturbation. HYD.a Outer structure obtained from horizontal and temporal averaging of a hydrodynamical convection model (e.g. Stein & Nordlund 1991). This was extended into a...
The Sensitivity Of Various Mode Sets For Probing Differential Rotation Shear Zones (2007)
Jørgen Christensen-Dalsgaard, Jesper Schou, Michael J. Thompson, Juri Toomre
The potential of forthcoming datasets from GONG and SOI for resolving long-lived azimuthal jets and shearing flows is investigated. We construct various artificial datasets, containing noise...
Solar Structure Inversion With Lowl Data (2007)
Sarbani Basu, Jørgen Christensen-Dalsgaard, Danmarks Grundforskningsfond, Jesper Schou, Michael J. Thompson, Steven Tomczyk
We present inversion results for the radial hydrostatic structure of the Sun, using six months of oscillation data obtained with the LOWL instrument. This is the first extensive homogeneous set of...
Convective Envelopes in Solar-Type Stars: What can we learn from their seismic study? (2007)
Jørgen Christensen-Dalsgaard, Michael J. Thompson
Introduction Seismic studies of the base of the solar convective envelope have constrained the properties at that transition region (Christensen-Dalsgaard et al. 1995, and references therein), which...
Stellar Background Power Spectra From Hydrodynamical Simulations of Stellar Atmospheres (2007)
Regner Trampedach, Jørgen Christensen-Dalsgaard, Ake Nordlund, Robert F. Stein
The non-p-mode contribution to the temporal irradiance or velocity spectra of the Sun has for a long time been considered as noise, but in recent years it has gradually been appreciated as the signal...
Basic Aspects Of Stellar Structure And Pulsation (2007)
Jørgen Christensen-Dalsgaard, Danmarks Grundforskningsfond, Woiciech A. Dziembowski, Obserwatorium Astronomiczne, Uniwersytetu Warszawskiego
this paper; his (mostly pertinent) comments have substantially improved the presentation. JC-D was supported in part by the Danish National Research Foundation through the establishment of the...
Helioseismology, Solar Models and Solar Neutrinos (2007)
INTRODUCTION The early attempts to explain the so-called solar neutrino problem, i.e., the discrepancy between the measured flux of neutrinos and the predictions of solar models, generally...
Jørgen Christensen-Dalsgaard, Michael J. Thompson
The possibility of observing solar-type oscillations on other stars is of great relevance to investigating the uncertain aspects of the stars' internal structure. One of these aspects is...
Implications of Helioseismology for Stellar Structure and Evolution (1999)
Jørgen Christensen-Dalsgaard, Danmarks Grundforskningsfond
. The very accurate data now available on solar oscillation frequencies provide stringent constraints on the structure and dynamics of the solar interior, and hence on solar evolution. This is of...
Convective Contributions to the Frequencies of Solar Oscillations (1999)
Colin S. Rosenthal, Jørgen Christensen-Dalsgaard, Åke Nordlund, Robert F. Stein
. Differences between observed and theoretical eigenfrequencies of the Sun have characteristics which identify them as arising predominantly from properties of the oscillations in the vicinity of the...
Lecture Notes on Stellar Oscillations (1997)
t. Further comments and corrections are most welcome. Preface to 3rd edition The notes have been very substantially revised and extended in this edition, relative to the previous two editions. Thus...
Near-Surface Constraints On The Structure Of Stellar Convection Zones (1997)
Regner Trampedach, Jørgen Christensen-Dalsgaard, Danmarks Grundforskningsfond, Robert F. Stein
. By simulating the convection in the upper layers of six different stars and matching these simulations to 1D-mixing length models using the same input physics, we have been able to infer the...
This paper presents a method to verify (the internal consistency) and to validate (with respect to the purpose of the builders) Sequential Function Charts [8] (grafcets in French). The method is...
An Overview of the Conference (1996)
. An eminent solar physicist has been quoted as saying that "despite exquisite images we have of the Sun's surface, we know almost nothing about its interior" (Browne 1995). The...
Helioseismic estimation of convective overshoot in the Sun (1995)
The Sun, Jørgen Christensen-Dalsgaard, Michael J. Thompson
By using the periodic signal present in the frequencies of oscillation due to the base of the solar convection zone, Monteiro, Christensen-Dalsgaard & Thompson (1994) gave an upper limit to the...
Jørgen Christensen-Dalsgaard, Michael J. Thompson
The possibility of observing solar-type oscillations on other stars is of great relevance to investigating the uncertain aspects of the stars' internal structure. One of these aspects is...