The magnetosphere of the ultracool dwarf DENIS 1048-3956
V. Ravi, G. Hallinan, G. Hobbs, D. J. Champion

TL;DR
This study presents wide-band radio observations of the ultracool dwarf DENIS 1048-3956, revealing gyrosynchrotron emission characteristics and estimating magnetic field properties beyond the star's co-rotation radius.
Contribution
It provides the first wide-band radio spectrum of an ultracool dwarf and models its magnetic environment, explaining its radio emission and X-ray/radio luminosity relation.
Findings
Detected a stable power-law radio spectrum with spectral index 1.71.
Found circular polarization fractions of 0.25 to 0.4 at low frequencies.
Estimated magnetic field strength between 70 and 260 G at the co-rotation radius.
Abstract
Ultracool dwarfs, the least-massive contributors to the stellar mass function, exhibit striking magnetic properties that are inconsistent with trends for more massive stars. Here, we present the widest-band radio observations to date of an ultracool dwarf, DENIS-P J104814.9-395604, in four 2 GHz bandwidths between wavelengths of 1 cm and 10 cm. These data were obtained with the Australia Telescope Compact Array using the new Compact Array Broadband Backend instrument. We detected a stable negatively-sloped power-law spectrum in total intensity, with spectral index alpha=1.71+-0.09. Circular polarization fractions between 0.25 and 0.4 were found at the low-frequency end of our detection band. We interpret these results as indicative of gyrosynchrotron emission. We suggest that the radio emission originates from beyond the co-rotation radius, R_C, of the star. Adopting this model, we find…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
