Related papers: The pulsating yellow supergiant V810 Centauri
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…
The double main sequence identified in the globular cluster Omega Centauri has been interpreted using isochrones to indicate a large variation in the abundance of helium. If true, a helium enhancement carries strong implications for the…
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 BRITE-Constellation photometry of the beta Cep pulsator xi 1 CMa. Analysis of these data reveals a single pulsation period of 0.2095781(3) d, along with its first and second harmonics. We find no evidence for any other…
We present the discovery and characterization of a radio-bright binary in the Galactic globular cluster M10. First identified in deep radio continuum data from the Karl G. Jansky Very Large Array, M10-VLA1 has a flux density of $27\pm4$…
We computed a grid of theoretical models to fit the $\delta$ Scuti frequencies of CoRoT 100866999 detected earlier from the CoRoT timeserials. The pulsating primary star is determined to be a main sequence star with a rotation period of…
Context: Alpha Centauri is our closest stellar neighbor, at a distance of only 1.3 pc, and its two main components have spectral types comparable to the Sun. This is therefore a favorable target for an imaging search for extrasolar planets.…
Proxima Centauri is our nearest stellar neighbor and one of the most well-studied stars in the sky. In 2016, a planetary companion was detected through radial velocity measurements. Proxima Centauri b has a minimum mass of 1.3 Earth masses…
The energetic, eclipsing millisecond pulsar J1816+4510 was recently discovered in a low-frequency radio survey with the Green Bank Telescope. With an orbital period of 8.7 hr and minimum companion mass of 0.16 Msun it appears to belong to…
The photospheric radius is one of the fundamental parameters governing the radiative equilibrium of a star. We report new observations of the nearest solar-type stars Alpha Centauri A (G2V) and B (K1V) with the VLTI/PIONIER optical…
[Abbreviated] We have investigated the color-magnitude diagram of Omega Centauri and find that the blue main sequence (bMS) can be reproduced only by models that have a of helium abundance in the range Y=0.35-$0.40. To explain the faint…
We present two-dimensional gas-kinematic maps of the central region in Centaurus A. The adaptive optics (AO) assisted SINFONI data from the VLT have a resolution of 0.12" in K-band. The ionized gas species (Br_gamma, [FeII], [SiVI]) show a…
This investigation integrates five decades of ground-based photometric data from the AAVSO, AFOEV, ASAS, ASAS-SN, and SuperWASP surveys with recently acquired TESS observations, conducting a multi-wavelength and multi-phase photometric…
We have carried out single and multi-site photometry of the three Beta Cephei stars Beta and 15 CMa as well as KZ Mus. For the two stars in CMa, we obtained 270 h of measurement in the Stromgren uvy and Johnson V filters, while 150 h of…
In this paper we describe a new class of pulsating stars, the prototype of which is the bright, early, F-type dwarf, Gamma Doradus. These stars typically have between 1 and 5 periods ranging from 0.4 to 3 days with photometric amplitudes up…
We combine 9 ROSAT, 9 Chandra, and 2 XMM-Newton observations of the Cen~A galaxy to obtain the X-ray light curve of 1RXH J132519.8-430312 (=CXOU J132519.9$-$430317) spanning 1990 to 2003. The source reached a peak 0.1-2.4 keV flux…
We present the timing of the first five millisecond pulsars discovered in the globular cluster Omega Centauri and the discovery of a pulsar with a spin period of 3.68 ms. With a timing baseline of $\sim$3.5 yr we are able to measure the…
We present a simple model for the Double Periodic Variable (DPV) V495 Cen, which evolves as a binary system of intermediate mass, where the gainer cannot accrete at high rate, limited by the Eddington accretion rate, leading to the…
We report a multisite photometric campaign for the Beta Cep stars V2052 Oph and V986 Oph. 670 hours of high-quality differential photoelectric Stromgren, Johnson and Geneva time-series photometry were obtained with eight telescopes on five…
We report on a three year spectroscopic monitoring program of the H-alpha emission in the massive X-ray binary LS I +65 010 = 2S 0114+650, which consists of a B-supergiant and a slowly rotating X-ray pulsar. We present revised orbital…