1993/06/01 by Jean‐François Lestrade, R. B. Phillips, Mark Hodges +1 · 6 citations
Physics and Astronomy · #Stellar, planetary, and galactic studies #Astronomy and Astrophysical Research #Gamma-ray bursts and supernovae
paper · doi:10.1086/172798
openalex publication_date 1993/06/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/11
A minute displacement of the radio source in Algol was measured by VLBI during two consecutive orbital revolutions of the close binary. The magnitude of the displacement unambiguously indicates that the less massive star of the close binary, a K subgiant, is the star responsible for the nonthermal radio emission of the system. This is consistent with the idea that the radio emission in Algol is related to the strong magnetic activity of the subgiant. The orientation and sense of the displacement on the sky that are directly deduced from our astrometric VLBI observations imply: (1) that the orbital plane of the close binary is at P.A. = +52 deg +/- 5 deg; and (2) that the sense of circulation of the close binary is clockwise, as seen on the sky. Thus, the long-period and close binary orbital motions are almost orthogonal and counterrevolving and this is relevant for evolution and dynamical studies.