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Title: AURORAL RADIO EMISSION FROM STARS: THE CASE OF CU VIRGINIS

Abstract

CU Virginis is a rapidly rotating Magnetic Chemically Peculiar star with at present unique characteristics as a radio emitter. The most intriguing one is the presence of intense, 100% circularly polarized radiation ascribed to a cyclotron maser. Each time the star rotates, this highly beamed emission points two times toward the Earth, like a pulsar. We observed CU Vir in 2010 April with the Expanded Very Large Array in two bands centered at 1450 and 1850 MHz. We covered nearly the whole rotational period, confirming the presence of the two pulses at a flux density up to 20 mJy. Dynamical spectra, obtained with unprecedented spectral and temporal sensitivity, allow us to clearly see the different time delays as a function of frequency. We interpret this behavior as a propagation effect of the radiation inside the stellar magnetosphere. The emerging scenario suggests interesting similarities with the auroral radio emission from planets, in particular with the Auroral Kilometric Radiation from Earth, which originates at few terrestrial radii above the magnetic poles and was only recently discovered to be highly beamed. We conclude that the magnetospheres of CU Vir, Earth, and other planets, maybe also exoplanets, could have similar geometrical and physical characteristicsmore » in the regions where the cyclotron maser is generated. In addition, the pulses are perfect 'markers' of the rotation period. This has given us for the first time the possibility to measure with extraordinary accuracy the spin-down of a star on or near the main sequence.« less

Authors:
; ; ;  [1];  [2]
  1. INAF-Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123 Catania (Italy)
  2. Dipartimento di Fisica e Astronomia, Universita di Catania, Via Santa Sofia 78, 95123 Catania (Italy)
Publication Date:
OSTI Identifier:
21565443
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 739; Journal Issue: 1; Other Information: DOI: 10.1088/2041-8205/739/1/L10; Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; EMISSION; MAGNETIC FIELDS; MASERS; PLANETS; RADIOWAVE RADIATION; STARS; AMPLIFIERS; ELECTROMAGNETIC RADIATION; ELECTRONIC EQUIPMENT; EQUIPMENT; MICROWAVE AMPLIFIERS; MICROWAVE EQUIPMENT; RADIATIONS

Citation Formats

Trigilio, Corrado, Leto, Paolo, Umana, Grazia, Buemi, Carla S., and Leone, Francesco, E-mail: ctrigilio@oact.inaf.it. AURORAL RADIO EMISSION FROM STARS: THE CASE OF CU VIRGINIS. United States: N. p., 2011. Web. doi:10.1088/2041-8205/739/1/L10.
Trigilio, Corrado, Leto, Paolo, Umana, Grazia, Buemi, Carla S., & Leone, Francesco, E-mail: ctrigilio@oact.inaf.it. AURORAL RADIO EMISSION FROM STARS: THE CASE OF CU VIRGINIS. United States. doi:10.1088/2041-8205/739/1/L10.
Trigilio, Corrado, Leto, Paolo, Umana, Grazia, Buemi, Carla S., and Leone, Francesco, E-mail: ctrigilio@oact.inaf.it. Tue . "AURORAL RADIO EMISSION FROM STARS: THE CASE OF CU VIRGINIS". United States. doi:10.1088/2041-8205/739/1/L10.
@article{osti_21565443,
title = {AURORAL RADIO EMISSION FROM STARS: THE CASE OF CU VIRGINIS},
author = {Trigilio, Corrado and Leto, Paolo and Umana, Grazia and Buemi, Carla S. and Leone, Francesco, E-mail: ctrigilio@oact.inaf.it},
abstractNote = {CU Virginis is a rapidly rotating Magnetic Chemically Peculiar star with at present unique characteristics as a radio emitter. The most intriguing one is the presence of intense, 100% circularly polarized radiation ascribed to a cyclotron maser. Each time the star rotates, this highly beamed emission points two times toward the Earth, like a pulsar. We observed CU Vir in 2010 April with the Expanded Very Large Array in two bands centered at 1450 and 1850 MHz. We covered nearly the whole rotational period, confirming the presence of the two pulses at a flux density up to 20 mJy. Dynamical spectra, obtained with unprecedented spectral and temporal sensitivity, allow us to clearly see the different time delays as a function of frequency. We interpret this behavior as a propagation effect of the radiation inside the stellar magnetosphere. The emerging scenario suggests interesting similarities with the auroral radio emission from planets, in particular with the Auroral Kilometric Radiation from Earth, which originates at few terrestrial radii above the magnetic poles and was only recently discovered to be highly beamed. We conclude that the magnetospheres of CU Vir, Earth, and other planets, maybe also exoplanets, could have similar geometrical and physical characteristics in the regions where the cyclotron maser is generated. In addition, the pulses are perfect 'markers' of the rotation period. This has given us for the first time the possibility to measure with extraordinary accuracy the spin-down of a star on or near the main sequence.},
doi = {10.1088/2041-8205/739/1/L10},
journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 1,
volume = 739,
place = {United States},
year = {2011},
month = {9}
}