相关论文: Fourier Analysis of Spectra of Solar-Type Stars
Stellar spectra with a high resolution of 115000 obtained with the HARPS spectrograph provide an opportunity to examine turbulence velocities and their depth distributions in the photosphere of stars. Fourier analysis was performed for 17…
The Fourier Transform method is a popular tool to derive the rotational velocities of stars from their spectral line profiles. However, its domain of validity does not include line-profile variables with time-dependent profiles. We…
We used spectral observations of Fe I line profiles with a 200 000 resolution to determine micro and macroturbulent velocities in the atmospheres of the Sun as a star, {\alpha} Cen A, Procyon ({\alpha} CMi), Arcturus ({\alpha} Boo), and…
The velocity distribution of the large and small-scale motion in solar photosphere has been obtained by crossing method based on fitting the observed and calculated equivalent widths as well as the central depths of the spectral lines at…
We describe our procedure to determine effective temperatures, rotational velocities, microturbulent velocities, and chemical abundances in the atmospheres of Sun-like stars. We use independent determinations of iron abundances using the…
We present a comprehensive study that applies the Fourier transform to a sample of O and early B-type stars (either dwarfs, giants, or supergiants) to determine their projected rotational velocities, compare with previous values obtained…
We assemble a homogeneous database of precise and consistent determinations of effective temperature, surface gravity, projected rotational rate, and macro- and micro-turbulent velocities for over 1800 Galactic stars spanning spectral types…
It is known that stellar differential rotation can be detected by analyzing the Fourier transform of spectral line profiles, since the ratio of the 1st- and 2nd-zero frequencies is a useful indicator. This approach essentially relies on the…
The solar photosphere provides us with a laboratory for understanding turbulence in a layer where the fundamental processes of transport vary rapidly and a strongly superadiabatic region lies very closely to a subadiabatic layer. Our tools…
The Doppler line shifts in the spectra of the Sun and stars with effective temperatures from 4800 to 6200 K were measured and the average connective (granulation) velocities were estimated. The absolute scale of the line shifts for the…
Context: Rotation plays a key role in the life cycles of stars with masses above 8 Msun. Hence, accurate knowledge of the rotation rates of such massive stars is critical for understanding their properties and for constraining models of…
A programme to observe all A dwarfs in open clusters brighter than V=6.5 mag of various ages and in the field was initiated several years ago. In this work we present the current status of microturbulent velocity for A and F dwarfs. We have…
Finding low-mass planets around solar-type stars requires to understand the physical variability of the host star, which greatly exceeds the planet-induced radial-velocity modulation. This project aims at analyzing - observationally and…
Here we determine the projected rotational velocity of 10 Be stars using Fourier Transform Method. Also, we discuss the gravity darkening and extend of deviation from solid body rotation for our sample of stars. We found that 7 of…
We have analysed the asymmetry of lines Fe I and Fe II in spectra of a solar flux using three FTS atlases and the HARPS atlas and also in spectra of 13 stars using observation data on the HARPS spectrograph. To reduce observation noise…
With an aim of getting information on the equatorial rotation velocity (v_e) of Sirius A separated from the inclination effect (sin i), a detailed profile analysis based on the Fourier transform technique was carried out for a large number…
While the effect of rotation on spectral lines is complicated in rapidly-rotating stars because of the appreciable gravity-darkening effect differing from line to line, it is possible to make use of this line-dependent complexity to…
We obtained high quality spectra of 135 stars of spectral types F and later and derived ``overall'' broadening functions in selected wavelength regions utilizing a Least Squares Deconvolution (LSD) procedure. Precision values of the…
Stellar radial velocities play a fundamental role in the discovery of extrasolar planets and the measurement of their physical parameters as well as in the study of stellar physical properties. We investigate the impact of the solar…
The Rossiter-McLaughlin effect observed for transiting exoplanets often requires prior knowledge of the stellar projected equatorial rotational velocity. This is usually provided by measuring the broadening of spectral lines, however this…