相关论文: The acoustic spectrum of alpha Cen A

We have made a clear detection of p-mode oscillations in the nearest solar-like G2V star $\alpha$ Cen A with the CORALIE spectrograph on the 1.2-m Swiss telescope at the ESO La Silla Observatory. We report the 5 nights of observation on…

We have made velocity observations of the star alpha 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 separations as a function of frequency. The mode…

This paper presents the analysis of Doppler p-modes of the F9 V star beta Virginis obtained with the spectrograph CORALIE in March 2003. Eleven nights of observations have made it possible to collect 1293 radial velocity measurements with a…

Asteroseismology provides a unique tool for studying stellar interiors. Recently p modes have been detected on the bright solar-like star alpha Cen A thanks to high-precision radial-velocity measurements. However a better characterisation…

We report Doppler measurements of alpha Cen A from time-series spectroscopy made with UCLES at the 3.9-m AAT. Wavelength calibration using an iodine absorption cell produced high-precision velocity measurements, whose power spectrum shows…

A set of long and nearly continuous observations of alpha Centauri A should allow us to derive an accurate set of asteroseismic constraints to compare to models, and make inferences on the internal structure of our closest stellar…

We analyse our recently-published velocity measurements of alpha Cen A (Butler et al. 2004). After adjusting the weights on a night-by-night basis in order to optimize the window function to minimize sidelobes, we extract 42 oscillation…

As a part of an on-going program to explore the signature of p-modes in solar-like stars by means of high-resolution absorption lines pectroscopy, we have studied four stars (alfaCMi, etaCas A, zetaHer A and betaVir). We present here new…

Hydrodynamical, 3D simulations of the outer layers of the Sun and Alpha Cen A are used to obtain constraints on the properties of turbulent convection in such stars. These constraints enable us to compute - on the base of a theoretical…

The F5 subgiant Procyon A (alpha CMi, HR 2943) was observed with the Coralie fiber-fed echelle spectrograph on the 1.2-m Swiss telescope at La Silla in February 1999. The resulting 908 high-accuracy radial velocities exhibit a mean noise…

We have made differential radial velocity measurements of the star alpha Cen A using two spectrographs, UVES and UCLES, both with iodine absorption cells for wavelength referencing. Stellar oscillations are clearly visible in the time…

This paper presents an analysis of observational data on the p-mode spectrum of the star alpha Cen B and a comparison with theoretical computations of the stochastic excitation and damping of the modes. We find that at frequencies > 4500…

We present results of fitting the 50-day time series of photometry of alpha Cen A taken by the WIRE satellite in 1999. Both power spectrum and autocovariance function (ACF) fitting techniques were used in an attempt to determine mode…

We analyze the photometric short-cadence data obtained with the Kepler Mission during the first eight months of observations of two solar-type stars of spectral types G and F: KIC 11395018 and KIC 11234888 respectively, the latter having a…

We report the most sensitive search yet made for solar-like oscillations. We observed the star alpha Cen A in Balmer-line equivalent widths over six nights with both the 3.9m Anglo-Australian Telescope and the ESO 3.6m telescope. We set an…

At radio wavelengths, solar-type stars emit thermal free-free and gyroresonance, gyrosynchrotron, and impulsive coherent emission. Thermal free-free emission originates at layers where the optical depth is close to unit, while high…

The Rossi X-ray Timing Explorer made a short (10 ks) observation of the radio galaxy Centaurus A on 14 August 1996. Analysis of the combined 2.5-240 keV spectrum has revealed a heavily absorbed(NH=9.42+/-0.24 e22 cm-2) primary power law…

We present a spectrum of Sgr A* observed simultaneously on June 17, 2003 at wavelengths from 90 to 0.7 cm with the VLA. In the spectrum, we also include the measurements of Sgr A* observed on the same day with the GMRT at 49 cm, the SMA at…

After more than one year of operation, the Kepler photometer has already provided exquisite data of solar-type stars. During the survey phase, 42 stars have been continuously observed. It appeared that five stars show evidence of…

Spectroscopic high-resolution observations were performed with fiber-fed cross-dispersed echelle spectrographs in order to measure the fluctuations in radial velocities of a sample of bright stars that are likely to undergo solar-like…