Abstract Details
| Name: Barnali Das Affiliation: NCRA-TIFR Conference ID: ASI2018_1597 Title : Discovery of Electron Cyclotron MASER Emission from the magnetic chemically peculiar star HD 133880 Authors and Co-Authors : Poonam Chandra (National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune, India) Gregg A. Wade (Department of Physics, Royal Military College of Canada, Canada) Abstract Type : Contributed Talk Abstract Category : Stars,ISM and the Galaxy Abstract : In this talk, we present the discovery of coherent radio emission from the magnetic chemically peculiar (MCP) star HD 133880. This young main sequence star is only the second MCP star (after CU Vir, in which the phenomenon was discovered 17 years earlier) to show this phenomenon. We will present observations of HD133880 obtained at 610 MHz with the Giant Metrewave Radio Telescope (GMRT) covering nearly the full rotation cycle of the star. The observations indicate narrow pulses in the light curve, corresponding to an order-of-magnitude flux density enhancement, nearly 100% right circularly polarised, and a brightness temperature in excess of 1E12 K. Using the phase of enhancement and the known longitudinal magnetic field variation, we attribute the enhancement to the Electron Cyclotron MASER Emission (ECME) process. The ECME is an important tool to probe any change in the stellar rotational period. This discovery is important since it shows that ECME is not a phenomenon unique to CU Vir, and if probed at low enough frequencies other MCP stars may show this phenomenon too. Our study emphasizes the need to obtain more observations of MCP stars at low radio frequencies (currently very few observations exist for frequencies below 1420 MHz) so that we can also answer the question of whether ECME is a characteristic of MCP stars, which will significantly improve our understanding of the magnetospheric physics of this class of stars. |