SPECTROSCOPIC ANALYSIS OF THE RS CVn STAR EI Eri

A probable RS CVn star which sometimes stops its eclipses ⋆

We report the discovery of a new variable star, called S 10947 Aql, as the likely optical counterpart of RX J2009.8+1557. The optical variability pattern as well as the detected X-ray emission suggest that it is a chromospherically active binary of the RS Canum Venaticorum (≡ RS CVn) type. We discovered an occasional disappearance of the eclipsing minima as well as large variations in the eclip...

VLBI imaging of the RS CVn binary star system HR 5110

We present VLBI images of the RS CVn binary star HR 5110 (=BH CVn; HD 118216), obtained from observations made at 8.4 GHz on 1994 May 29/30 in support of the NASA/Stanford Gravity Probe B project. Our images show an emission region with a core-halo morphology. The core was 0.39 ± 0.09 mas (FWHM) in size, or 66%±20% of the 0.6 ±0.1 mas diameter of the chromospher-ically active K subgiant star in...

VLA multifrequency observations of RS CVn binaries

We present multiepoch Very Large Array (VLA) observations at 1.4 GHz, 4.9 GHz, 8.5 GHz and 14.9 GHz for a sample of eight RS CVn binary systems. Circular polarization measurements of these systems are also reported. Most of the fluxes observed are consistent with incoherent emission from mildly relativistic electrons. Several systems show an increase of the degree of circular polarization with ...

Quiescent and Flaring Structure in Rs Cvn

The new AM CVn star in Hydra

High speed photometry of the new AM CVn star in Hya (previously known as SN2003aw), spectroscopically identified by Chornock & Filippenko, shows it to have a superhump period of 2041.5 ± 0.3 s. We find a range of brightness from V ∼ 16.5 to 20.3, presumably caused by variations in the rate of mass transfer. In the intermediate state the system cycles in brightness with a period of ∼ 16 h and ra...