Eclipsing behaviour of the radio emission in the Algol system V505 Sagittarii.|
Gunn A. G., Brady P. A., Migenes V., Spencer R. E., Doyle J. G.,
MNRAS, 1999, 304, 611-621.
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We present radio interferometric observations of the EA2 Algol-type
binary system V505 Sagitarii made with the ATNF Compact Array at 6 cm
and 3.6 cm over one orbital cycle (1.18 days). We obtained a strong
detection of the source (1.5 mJy at 6 cm and 1.4 mJy at 3.6 cm) and
derive a brightness temperature for the emitting region of Tb
~2.7 10^9 K, a magnetic field strength of 17 G < B < 170 G
and an electron density of Ne ~ 3.7 10^8 cm-3. The
radio flux density levels show a clear modulation with evidence of
eclipses of the emission region at both conjunctions of the
binary. The form of the light curve implies that the radio source
involves at least some enhanced emission in the intra-binary region.
This has important consequences for the details of coronal formation
and field interaction in active close binary stars. We discuss some
scenarios for the formation of intra-binary active regions in
Algol-type binary systems.