Related papers: A prescription for the asteroseismic surface corre…
Quantitative helio- and asteroseismology require very precise measurements of the frequencies, amplitudes, and lifetimes of the global modes of stellar oscillation. It is common knowledge that the precision of these measurements depends on…
Stars are not perfectly spherically symmetric. They are deformed by rotation and magnetic fields. Until now, the study of stellar shapes has only been possible with optical interferometry for a few of the fastest-rotating nearby stars. We…
The asteroseismic analysis of stellar power density spectra is often computationally expensive. The models used in the analysis may use several dozen parameters to accurately describe features in the spectra caused by oscillation modes and…
The success of helioseismology is due to its capability to accurately measure the p-mode parameters of the solar eigenmode spectrum, which allow us to infer unique information about the internal structure and dynamics of the Sun. It also…
Stellar models rely on a number of free parameters. High-quality observations of eclipsing binary stars observed by Kepler offer a great opportunity to calibrate model parameters for evolved stars. Our study focuses on six Kepler red giants…
Oscillations occur in stars of most masses and essentially all stages of evolution. Asteroseismology is the study of the frequencies and other properties of stellar oscillations, from which we can extract fundamental parameters such as…
Asteroseismology provides global stellar parameters such as masses, radii or surface gravities using the mean global seismic parameters as well as the effective temperature for thousands of low-mass stars $(0.8 M_\odot <M<3 M_\odot)$. This…
Context: Asteroseismic surface gravity values can be of importance in determining spectroscopic stellar parameters. The independent log(g) value from asteroseismology can be used as a fixed value in the spectroscopic analysis to reduce…
Solar p-mode frequencies vary with solar activity. It is important to take this into account when comparing the frequencies observed from epochs that span different regions of the solar cycle. We present details of how to correct observed…
Precise stellar masses and radii can be determined using asteroseismology, but their accuracy must be tested against independent estimates. Using radii derived from Gaia DR2 parallaxes, we test the accuracy of asteroseismic radii for a…
Asteroseismology of solar-type stars is an important tool for constraining stellar parameters and internal structure. Several frequency combinations are largely used for comparisons between models and observations. In particular, the…
Small cyclic variations in the frequencies of acoustic modes are expected to be a common phenomenon in solar-like pulsators, as a result of stellar magnetic activity cycles. The frequency variations observed throughout the solar and stellar…
The surface errors of freeform surfaces reflect the manufacturing complexities and significantly impact the feasibility of processing designed optical systems. With multiple degrees of freedom, freeform surfaces pose challenges in surface…
Variability in the time series brightness of a star on a timescale of 8 hours, known as 'flicker', has been previously demonstrated to serve as a proxy for the surface gravity of a star by Bastien et al. (2013). Although surface gravity is…
Asteroseismology involves using the resonant frequencies of a star to infer details about its internal structure and evolutionary state. Oscillation frequencies are most useful when accompanied by accurate measurements of the more…
Reconstruction of the point spread function (PSF) plays an important role in many areas of astronomy, including photometry, astrometry, galaxy morphology, and shear measurement. The atmospheric and instrumental effects are the two main…
We present corrections for the change in the apparent scalelengths, central surface brightnesses and axis ratios due to the presence of dust in pure disk galaxies, as a function of inclination, central face-on opacity in the B-band…
This study investigates the variability of the theoretical correction factor, $f_{\Delta \nu}$, used in red giant branch (RGB) scaling relations, arising from different assumptions in stellar model computations. Adopting a commonly used…
Radial differential rotation is an important parameter for stellar dynamo theory and for understanding angular momentum transport. We investigate the potential of using a large number of similar stars simultaneously to constrain their…
Stellar surface magnetoconvection (granulation) creates asymmetries in the observed stellar absorption lines that can subsequently manifest themselves as spurious radial velocities shifts. In turn, this can then mask the Doppler-reflex…