| 12th of September 2019 |
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| Radio bursts from from a nearby star |
| by Zic et al. |
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Stars classified as active M-dwarfs are known to produce bursts of
radio emission, and multi-wavelength studies have shown that magnetic
activity, similar to that observed on the Sun, occurs in these stars.
UV Ceti is a prototypical flare star, and is part of a binary star
system 8.8 light years from our solar system. Bursts of radio
emission from UV Ceti were first reported in the 1960s in mega-hertz
band, and in the 1980s is was found these extended to giga-hertz
frequencies.
Zic et al. have recently presented ASKAP observations of UV Ceti at a central frequency of 888 MHz. Several periodic, coherent bursts occurring over a timescale consistent with the rotational period of UV Ceti were detected. The properties of the bursts confirm previous suggestions that they originate from an electron cyclotron maser instability in the stellar atmosphere. The image above shows the frequency-averaged light curve for UV Ceti on 2019 March 7, with the total intensity (Stokes I) plotted together with linear (Q, U) and circular (V) polarisation components. Eight clearly separated pulses were detected at this epoch. These pulses appear to be within two distinct sets separated by about 5.4 hours, which is consistent with previous measurement of the star's rotation period. These results demonstrate the capabilities of ASKAP for detecting polarised, coherent bursts from active stars and other systems. More details are published in the paper, published in Monthly Notices of the Royal Astronomical Society. |