Investigating Ca II emission in the RS CVn binary ER Vulpeculae using the Broadening Function Formalism

Abstract

The synchronously rotating G stars in the detached, short-period (0.7 d), partially eclipsing binary, ER Vul, are the most chromospherically active solar-type stars known. We have monitored activity in the Ca II H & K reversals for almost an entire orbit. Rucinski's Broadening Function Formalism allows the photospheric contribution to be objectively subtracted from the highly blended spectra. The power of the BF technique is also demonstrated by the good agreement of radial velocities with those measured by others from less crowded spectral regions. In addition to strong Ca II emission from the primary and secondary, there appears to be a high-velocity stream flowing onto the secondary where it stimulates a large active region on the surface 30 - 40 degrees in advance of the sub-binary longitude. A model light curve with a spot centered on the same longitude also gives the best fit to the observed light curve. A flare with approximately 13% more power than at other phases was detected in one spectrum. We suggest ER Vul may offer a magnified view of the more subtle chromospheric effects synchronized to planetary revolution seen in certain `51 Peg'-type systems.

arXiv commentAccepted to AJ; 17 pages and 16 figures

References in corpus (5)

• Hot Jupiters and Hot Spots: The Short- and Long-term Chromospheric Activity on Stars with Giant Planets
• Radial Velocity Studies of Close Binary Stars.VII. Methods and Uncertainties
• Differential rotation in rapidly rotating F-stars
• Stellar differential rotation from direct starspot tracking
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Cited by in corpus (8)

• The On/Off Nature of Star-Planet Interactions
• The Dynamics of Stellar Coronae Harboring Hot-jupiters I. A Time-dependent MHD Simulation of the Interplanetary Environment in the HD 189733 Planetary System
• The Impact of Hot Jupiters on the Spin-down of their Host Stars
• Interactions of the magnetospheres of stars and close-in giant planets
• The Dynamics of Stellar Coronae Harboring Hot-jupiters II. A Space Weather Event on A Hot-jupiter
• A bimodal correlation between host star chromospheric emission and the surface gravity of hot Jupiters
• Doppler images of the eclipsing binary ER Vulpeculae
• Magnetic fields of Sun-like stars