Related papers: MOST detects corotating bright spots on the mid-O …

Context. 55 Cnc e is a transiting super-Earth orbiting a solar-like star with an orbital period of 17.7 hours. In 2011, using the MOST space telescope, a quasi-sinusoidal modulation in flux was detected with the same period as the planetary…

X Persei is a persistent low-luminosity X-ray pulsar of period of $\sim$835 s in a Be binary system. The field strength at the neutron star surface is not known precisely, but indirect signs indicate a magnetic field above $10^{13}$ G,…

We present strong evidence for a rotation period of 2.0406 d of the O giant $\xi$ Persei, derived from the NIV $\lambda$1718 wind line in 12 yr of IUE data. We predict that $\xi$ Per has a magnetic dipole field, with superposed variable…

We use TESS 10-minute Full Frame Images (Sectors 27-55) to study a sample of 1708 stars within 500 pc of the Sun that lie in a narrow colour range in the centre of the delta Scuti instability strip (0.29 < BP-RP < 0.31). Based on the…

We report on the measurement of transit times for the HD 209458 planetary system from photometry obtained with the MOST (Microvariability & Oscillations of STars) space telescope. Deviations from a constant orbital period can indicate the…

With the construction of the VLTI (Very Large Telescope Interferometer of the European Observatory ESO for the southern hemisphere) it is now possible to make observations with resolutions of the order of milli-arc-seconds, especially in IR…

We report on an analysis of high-precision, multi-colour photometric observations of the rapidly-oscillating Ap (roAp) star $\alpha$ Cir. These observations were obtained with the BRITE-Constellation, which is a coordinated mission of five…

The quantity and quality of satellite photometric data strings is revealing details in Cepheid variation at very low levels. Specifically, we observed a Cepheid pulsating in the fundamental mode and one pulsating in the first overtone with…

A quantitative analysis of time series of ultraviolet spectra from a sample of 10 bright O-type stars (cf. Kaper et al. 1996, Paper I) is presented. The migrating discrete absorption components (DACs), responsible for the observed…

We argue that the non-detection of oscillations in Procyon by the MOST satellite reported by Matthews et al. (2004) is fully consistent with published ground-based velocity observations of this star. We also examine the claims that the MOST…

We aim to understand the interplay between non-radial oscillations and stellar magnetic activity and test the feasibility of doing asteroseismology of magnetically active stars. We analyze 30 years of photometric time-series data, 3 years…

We present high resolution images of the young rapidly rotating K3 dwarf Speedy Mic (BO Mic, HD 197890). The photospheric spot maps reveal a heavily and uniformly spotted surface from equatorial to high latitude regions. Contrary to many…

We have studied variability of the spectral lines of the OB star $\delta $Ori A--the brightest component of the $\delta $Ori triple system. Forty spectra with signal-to-noise ratios $\approx$500--800 and a time resolution of four minutes…

The rapidly rotating Be star phi Persei was spun up by mass and angular momentum transfer from a now stripped-down, hot subdwarf companion. Here we present the first high angular resolution images of phi Persei made possible by new…

We present a large sample of stellar rotation periods for Kepler Objects of Interest (KOIs), based on three years of public Kepler data. These were measured by detecting periodic photometric modulation caused by star spots, using an…

We undertook a multisite photometric campaign for the Beta Cephei star Nu Eridani. More than 600 hours of differential photoelectric uvyV photometry were obtained with 11 telescopes during 148 clear nights. The frequency analysis of our…

KOI-13 is the first known transiting system exhibiting light curve distortions due to gravity darkening of the rapidly rotating host star. In this paper we analyze publicly available Kepler Q2--Q3 short-cadence observations, detecting a…

As a continuation of our previous studies in 2007 and 2008, new photometric observations of the T Tauri star TW Hya obtained by the MOST satellite and the ASAS project over 40 days in 2009 with temporal resolution of 0.2 days are presented.…

The transient optical source MASTER OT J072007.30+451611.6 has been recently discovered and proposed as a peculiar polar with an unusually high amplitude of the orbital brightness variation in the optical of $\sim$3 mag. To clarify its…

We identify delta Scuti pulsators amongst members of the recently-discovered Cep--Her Complex using light curves from the Transiting Exoplanet Survey Satellite (TESS). We use Gaia colours and magnitudes to isolate a subsample of provisional…