We have identified a new early T dwarf only 3.6 pc from the Sun, as a common proper motion companion (separation 1459 AU) to the K5V star varepsilon Indi (HD...
Variability and Emission Mechanisms in SEYFERT-1 Galaxies - a Near Infrared Outburst in NGC4051
In the course of a 2.2 micron monitoring programme of nearby Seyfert 1 galaxies, we have detected an outburst in NGC 4051 in which the source flared and dimmed...
Variability in the CoRoT photometry of three hot O-type stars. HD 46223, HD 46150, and HD 46966
Context. The detection of pulsational frequencies in stellar photometry is required as input for asteroseismological modelling. The second short run (SRa02) of...
Variability of OB stars from TESS southern Sectors 1-13 and high-resolution IACOB and OWN spectroscopy
Context. The lack of high-precision long-term continuous photometric data for large samples of stars has impeded the large-scale exploration of pulsational...
Variability of the blazar 4C 38.41 (B3 1633+382) from GHz frequencies to GeV energies
Context. After years of modest optical activity, the quasar-type blazar 4C 38.41 (B3 1633+382) experienced a large outburst in 2011, which was detected...
Variability of the polarization profiles of the Ba II D{2} line in the solar atmosphere
Resonance-scattering polarization and the Hanle effect are powerful but seldom exploited probes into the magnetism of the quiet solar atmosphere. They are also...
Variability of the transitional T Tauri star T Chamaeleontis
Context: It is known that for solar-mass stars planet formation begins in a circumstellar disc. The study of transitional objects exhibiting clear signs of...
Variable central stars of young planetary nebulae. I. Photometric multisite observations of IC 418.
We report the results of a photometric multisite campaign devoted to HD 35914, the variable central star of the Planetary Nebula IC 418. From the analysis of...
Variation in sunspot properties between 1999 and 2011 as observed with the Tenerife Infrared Polarimeter
Aims: We study the variation in the magnetic field strength and the umbral intensity of sunspots during the declining phase of the solar cycle No. 23 and in the...