Radio emission from the magnetically active M dwarf UV Ceti from 1 GHz to 105 GHz

Fuente: arXiv
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Autores principales: Plant, Kathryn, Hallinan, Gregg, Bastian, Tim
Formato: Preprint
Publicado: 2024
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author Plant, Kathryn
Hallinan, Gregg
Bastian, Tim
author_facet Plant, Kathryn
Hallinan, Gregg
Bastian, Tim
contents BL and UV Ceti are a nearby (2.7 pc) binary system with similar masses, spectral types, and rapid rotation rates, but very different magnetic activity. UV Ceti's much stronger large-scale magnetic field may cause this difference, highlighting key unanswered questions about dynamo processes in fully convective objects. Here we present multi-epoch characterization of the radio spectrum of UV Ceti spanning 1-105 GHz, exhibiting flared emission similar to coronal activity, auroral-like emission analogous to planetary magnetospheres, and slowly-varying persistent emission. Radio observations are a powerful means to probe the role that the large-scale magnetic field of UV Ceti has in non-thermal particle acceleration, because radio-frequency phenomena result from both the activity of small-scale field features as well as large-scale auroral current systems. We find temporal variability at all bands observed, and a hint of rotational modulation in the degree of circular polarization up to 40 GHz. The persistent component of the emission is fairly constant from 1-105 GHz, making optically thick emission or optically thin gyrosynchrotron from electrons with an isotropic pitch angle distribution unlikely. We discuss the possibility of emission mechanisms analogous to Jupiter's radiation belts.
format Preprint
id arxiv_https___arxiv_org_abs_2406_17280
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Radio emission from the magnetically active M dwarf UV Ceti from 1 GHz to 105 GHz
Plant, Kathryn
Hallinan, Gregg
Bastian, Tim
Solar and Stellar Astrophysics
BL and UV Ceti are a nearby (2.7 pc) binary system with similar masses, spectral types, and rapid rotation rates, but very different magnetic activity. UV Ceti's much stronger large-scale magnetic field may cause this difference, highlighting key unanswered questions about dynamo processes in fully convective objects. Here we present multi-epoch characterization of the radio spectrum of UV Ceti spanning 1-105 GHz, exhibiting flared emission similar to coronal activity, auroral-like emission analogous to planetary magnetospheres, and slowly-varying persistent emission. Radio observations are a powerful means to probe the role that the large-scale magnetic field of UV Ceti has in non-thermal particle acceleration, because radio-frequency phenomena result from both the activity of small-scale field features as well as large-scale auroral current systems. We find temporal variability at all bands observed, and a hint of rotational modulation in the degree of circular polarization up to 40 GHz. The persistent component of the emission is fairly constant from 1-105 GHz, making optically thick emission or optically thin gyrosynchrotron from electrons with an isotropic pitch angle distribution unlikely. We discuss the possibility of emission mechanisms analogous to Jupiter's radiation belts.
title Radio emission from the magnetically active M dwarf UV Ceti from 1 GHz to 105 GHz
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2406.17280