Corrado Trigilio (INAF - Catania Astrophysical Observatory)

The neverending story of CU Virginis -- Corrado Trigilio Colloquium

Marsfield Lecture Theatre

Abstract

I will present recent results on modeling of the peculiar radio star CU Vir. During the observational campaigns in a sample of MCP stars, we serendipitous discovered an anomalous emission in CU Virginis. This emission has been ascribed as due to cyclotron maser instability above the pole of the star. The emission is persistent, as it has been observed over more than a decade, making the star as a sort of radio lighthouse, like a pulsar.

This precise timing allow us to get very accurate measurements of the stellar rotational period, and to detect improvvise breaking of the star. Although no definitive answer to the question of this behaviour still
exists, the radio monitoring of CU Vir can give important results on the angular momentum evolution of MS stars.
But the most important thing is probably the maser emission per se, as it allows us to study the magnetized plasma around the star. A similar behaviour is observed in giant planets as well as in the terrestrial magnetosphere, and probably also in cool M-type stars as well as brown dwarfs, where occasional emission like CU Vir as been
detected. The search of similar stellar objects continues, and the probability of detection of them with the incoming radio array like SKA is high. The detectability of CU Vir type star in EMU is also discussed.