We have measured velocity maps of a round sunspot near the center of the solar disk. We derive the small-scale velocity field of the penumbra in the deep photosphere. Superimposed on a radial outflow, we find up– and downflows, which are associated with bright and dark features: The flow in the dark component of the penumbra has a larger inclination angle with respect to the surface normal than...

RXJ0501.7–0359 is a new V ∼ 17mag eclipsing polar discovered during the ROSAT all-sky survey (RASS). Extensive follow-up observations at X-ray (pointed ROSAT PSPC and HRI observations) and optical (time-resolved photometry and spectroscopy) wavelengths were obtained which allowed us to determine a very precise orbital period and to provide constraints for the masses of the binary components and...

The issue of the multiplicity of massive stars can be addressed through the investigation of radial velocity variations in spectral lines, or by the detection of blended asymmetric line profiles. However, the absence of such signatures should by no mean be interpreted as an evidence that the star is single. The non-detection of the spectral line of the secondary can indeed be due to a high lumi...

The Microvariability and Oscillations of STars (MOST ) photometric satellite observed three rotations of Eri continuously in late 2005. We detected two spots ( m 0:01) at different latitudes (20N0, 31N5) revolving with different periods (11.35 days, 11.55 days), from which we derive a differential rotation coefficient, k 1⁄4 0:11þ:03 :02, in agreement with the prediction by Brown and coworkers ...

We present the first detection of the mass donor star in the prototype X-ray binary Scorpius X-1. Phase resolved spectroscopy revealed narrow emission lines components from the irradiated secondary star. Radial velocity fits to the Bowen blend emission are used to establish an absolute orbital ephemeris and derive an accurate value for the systemic velocity; γ = −113.8 ± 0.6 km s. Emission from...

2MASS J03202839−0446358AB is a recently identified, late-type M dwarf/T dwarf spectroscopic binary system for which both the radial velocity orbit for the primary and spectral types for both components have been determined. By combining these measurements with predictions from four different sets of evolutionary models, we determine a minimum age of 2.0±0.3 Gyr for this system, corresponding to...

It has been suggested that the long-lived residual radial velocity variations observed in the precision radial velocity measurements of the primary of γ Cephei (HR8974, HD222404, HIP116727) are likely due to a Jupiter-like planet around this star (Hatzes et al. 2003). In this paper, the orbital dynamics of this plant is studied and also the possibility of the existence of a hypothetical Earth-l...

The images taken by the Heliospheric Imagers (HIs), part of the SECCHI imaging package onboard the pair of STEREO spacecraft, provide information on the radial and latitudinal evolution of the plasma compressed inside corotating interaction regions (CIRs). A plasma density wave imaged by the HI instrument onboard STEREO-B was found to propagate towards STEREO-A, enabling a comparison between si...

We measured the radial velocity curve of the companion of the neutron star X-ray transient XTE J2123–058. Its semi-amplitude (K2) of 298.5±6.9 km s−1 is the highest value that has been measured for any neutron star LMXB. The high value for K2 is, in part, due to the high binary inclination of the system but may also indicate a high neutron star mass. The mass function ( f2) of 0.684± 0.047M⊙, a...

Our previous analyses of the redshifts and distances of galaxies included 55 spiral galaxies and 36 Type Ia Supernovae galaxies in three separate groups. All groups showed evidence that their radial velocities contain the same discrete velocity components that are predicted from the early work of Tifft. Here we examine another new source sample containing 83 ScI galaxies. When B-band distances ...