Related papers: A search for p-modes and other variability in the …
We analyse 829,481 stars from the Next Generation Transit Survey (NGTS) to extract variability periods. We utilise a generalisation of the autocorrelation function (the G-ACF), which applies to irregularly sampled time series data. We…
We explore the detection limits of the phase modulation (PM) method of finding binary systems among multi-periodic pulsating stars. The method is an attractive way of finding non-transiting planets in the habitable zones of intermediate…
The space telescope MOST is now providing us with extremely accurate low frequency p-mode oscillation data for the star Eta Boo. We demonstrate in this paper that these data, when combined with ground based measurements of the high…
Many stars exhibit stellar pulsations, favoring them for asteroseismic analyses. Interpreting the oscillations requires some knowledge of the oscillation mode geometry (spherical degree, radial and azimuthal orders). The delta Scuti stars…
Context: [abbreviated] Aims: Kepler data of three known Be stars are re-visited to establish their pulsational nature and assess the properties of additional, non-pulsational variations. The three program stars turned out to be one inactive…
The present paper describes the first results of an observational program intended to refine and extend the existing vsini measurements of metal-poor stars, with anemphasis on field evolved stars. The survey was carried out with the FEROS…
We have carried out a photometric and spectroscopic survey of bright high-amplitude delta Scuti (HADS) stars. The aim was to detect binarity and multiperiodicity (or both) in order to explore the possibility of combining binary star…
We report on optical high-dispersion spectroscopic monitoring observations of the Be/X-ray binary A0535+26/V725 Tau, carried out from November 2005 to March 2009. The main aim of these monitoring observations is to study spectral…
We have carried out single and multi-site photometry of the three Beta Cephei stars Beta and 15 CMa as well as KZ Mus. For the two stars in CMa, we obtained 270 h of measurement in the Stromgren uvy and Johnson V filters, while 150 h of…
The line profile variability and photometric variability of the O9.5 Vp star HD93521 are examined in order to establish the properties of the non-radial pulsations in this star. Fourier techniques are used to characterize the modulations of…
Dome A on the Antarctic plateau is likely one of the best observing sites on Earth thanks to the excellent atmospheric conditions present at the site during the long polar winter night. We present high-cadence time-series aperture…
The space-based Kepler mission provided four years of highly precise and almost uninterrupted photometry for hundreds of $\gamma$ Doradus stars and tens of SPB stars, finally allowing us to apply asteroseismology to these gravity mode…
Asteroseismic modelling of isolated star presents significant challenges due to the difficulty in accurately determining stellar parameters, particularly the stellar age. These challenges can be overcomed by observing stars in open…
Betelgeuse is a pulsating red supergiant whose brightness is semi periodically variable and in February 2020 reached a historical minimum, the Great Dimming. The aims of this study are to characterize Betelgeuse's variability based on…
The currently available Kepler light curves contain an outstanding amount of information but a detailed analysis of the individual oscillation modes in the observed power spectra, also known as peak bagging, is computationally demanding and…
A 2.1-year periodic oscillation of the gamma-ray flux from the blazar PG 1553+113 has previously been tentatively identified in almost 7 year of data from the Fermi Large Area Telescope. After 15 years of Fermi sky-survey observations,…
The rotational and magnetic properties of many magnetic hot stars are poorly characterized, therefore the MiMeS and BinaMIcS collaborations have collected extensive high-dispersion spectropolarimetric datasets of these targets. We present…
While long period variables (LPVs) have been extensively investigated, especially with MACHO and OGLE data for the Magellanic Clouds, there still exist open questions in their pulsations regarding the excitation mechanisms, radial order and…
The (magnetic) chemically peculiar (CP) stars of the upper main sequence are well-suited laboratories for investigating the influence of magnetic fields on the stellar surface because they produce abundance inhomogeneities (spots), which…
We report on quasi-periodic variability found in two blazars included in the Steward Observatory Blazar Monitoring data sample: the BL Lac object 3C 66A and the Flat Spectrum Radio Quasar B2 1633+38. We collect optical photometric and…