A combined multiwavelength VLA/ALMA/Chandra study unveils the complex magnetosphere of the B-type star HR5907

P. Leto, C. Trigilio, L. M. Oskinova, R. Ignace, C. S. Buemi, G. Umana, A. Ingallinera, F. Leone, N. M. Phillips, C. Agliozzo, H. Todt, L. Cerrigone

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Resumen

We present new radio/millimeter measurements of the hot magnetic star HR5907 obtained with the VLA and ALMA interferometers. We find that HR5907 is the most radio luminous early type star in the cm-mm band among those presently known. Its multi-wavelength radio light curves are strongly variable with an amplitude that increases with radio frequency. The radio emission can be explained by the populations of the non-thermal electrons accelerated in the current sheets on the outer border of the magnetosphere of this fast-rotating magnetic star. We classify HR5907 as another member of the growing class of strongly magnetic fastrotating hot stars where the gyro-synchrotron emission mechanism efficiently operates in their magnetospheres. The new radio observations of HR5907 are combined with archival X-ray data to study the physical condition of its magnetosphere. The X-ray spectra of HR5907 show tentative evidence for the presence of non-thermal spectral component. We suggest that non-thermal X-rays originate a stellar X-ray aurora due to streams of non-thermal electrons impacting on the stellar surface. Taking advantage of the relation between the spectral indices of the X-ray power-law spectrum and the non-thermal electron energy distributions, we perform 3-D modelling of the radio emission for HR5907. The wavelength-dependent radio light curves probe magnetospheric layers at different heights above the stellar surface. A detailed comparison between simulated and observed radio light curves leads us to conclude that the stellar magnetic field of HR 5907 is likely non-dipolar, providing further indirect evidence of the complex magnetic field topology of HR5907.

IdiomaEnglish
Páginas562-579
Número de páginas18
PublicaciónMonthly Notices of the Royal Astronomical Society
Volumen476
Número de edición1
DOI
EstadoPublished - 1 may 2018

Huella dactilar

magnetospheres
magnetosphere
magnetic stars
radio
stars
light curve
hot stars
radio emission
x rays
stellar magnetic fields
radio observation
current sheets
electron
borders
wavelengths
radio frequencies
energy distribution
synchrotrons
electrons
topology

Keywords

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

    Citar esto

    Leto, P. ; Trigilio, C. ; Oskinova, L. M. ; Ignace, R. ; Buemi, C. S. ; Umana, G. ; Ingallinera, A. ; Leone, F. ; Phillips, N. M. ; Agliozzo, C. ; Todt, H. ; Cerrigone, L. / A combined multiwavelength VLA/ALMA/Chandra study unveils the complex magnetosphere of the B-type star HR5907. En: Monthly Notices of the Royal Astronomical Society. 2018 ; Vol. 476, N.º 1. pp. 562-579.
    @article{1b3c3268bd474850a6ab88b75cb94d0d,
    title = "A combined multiwavelength VLA/ALMA/Chandra study unveils the complex magnetosphere of the B-type star HR5907",
    abstract = "We present new radio/millimeter measurements of the hot magnetic star HR5907 obtained with the VLA and ALMA interferometers. We find that HR5907 is the most radio luminous early type star in the cm-mm band among those presently known. Its multi-wavelength radio light curves are strongly variable with an amplitude that increases with radio frequency. The radio emission can be explained by the populations of the non-thermal electrons accelerated in the current sheets on the outer border of the magnetosphere of this fast-rotating magnetic star. We classify HR5907 as another member of the growing class of strongly magnetic fastrotating hot stars where the gyro-synchrotron emission mechanism efficiently operates in their magnetospheres. The new radio observations of HR5907 are combined with archival X-ray data to study the physical condition of its magnetosphere. The X-ray spectra of HR5907 show tentative evidence for the presence of non-thermal spectral component. We suggest that non-thermal X-rays originate a stellar X-ray aurora due to streams of non-thermal electrons impacting on the stellar surface. Taking advantage of the relation between the spectral indices of the X-ray power-law spectrum and the non-thermal electron energy distributions, we perform 3-D modelling of the radio emission for HR5907. The wavelength-dependent radio light curves probe magnetospheric layers at different heights above the stellar surface. A detailed comparison between simulated and observed radio light curves leads us to conclude that the stellar magnetic field of HR 5907 is likely non-dipolar, providing further indirect evidence of the complex magnetic field topology of HR5907.",
    keywords = "Radio continuum: Stars, Stars: Chemically peculiar, Stars: Early-type, Stars: Individual: HR 5907, Stars: Magnetic field, X-rays: Stars",
    author = "P. Leto and C. Trigilio and Oskinova, {L. M.} and R. Ignace and Buemi, {C. S.} and G. Umana and A. Ingallinera and F. Leone and Phillips, {N. M.} and C. Agliozzo and H. Todt and L. Cerrigone",
    year = "2018",
    month = "5",
    day = "1",
    doi = "10.1093/mnras/sty244",
    language = "English",
    volume = "476",
    pages = "562--579",
    journal = "Monthly Notices of the Royal Astronomical Society",
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    Leto, P, Trigilio, C, Oskinova, LM, Ignace, R, Buemi, CS, Umana, G, Ingallinera, A, Leone, F, Phillips, NM, Agliozzo, C, Todt, H & Cerrigone, L 2018, 'A combined multiwavelength VLA/ALMA/Chandra study unveils the complex magnetosphere of the B-type star HR5907' Monthly Notices of the Royal Astronomical Society, vol. 476, n.º 1, pp. 562-579. https://doi.org/10.1093/mnras/sty244

    A combined multiwavelength VLA/ALMA/Chandra study unveils the complex magnetosphere of the B-type star HR5907. / Leto, P.; Trigilio, C.; Oskinova, L. M.; Ignace, R.; Buemi, C. S.; Umana, G.; Ingallinera, A.; Leone, F.; Phillips, N. M.; Agliozzo, C.; Todt, H.; Cerrigone, L.

    En: Monthly Notices of the Royal Astronomical Society, Vol. 476, N.º 1, 01.05.2018, p. 562-579.

    Resultado de la investigación: Article

    TY - JOUR

    T1 - A combined multiwavelength VLA/ALMA/Chandra study unveils the complex magnetosphere of the B-type star HR5907

    AU - Leto, P.

    AU - Trigilio, C.

    AU - Oskinova, L. M.

    AU - Ignace, R.

    AU - Buemi, C. S.

    AU - Umana, G.

    AU - Ingallinera, A.

    AU - Leone, F.

    AU - Phillips, N. M.

    AU - Agliozzo, C.

    AU - Todt, H.

    AU - Cerrigone, L.

    PY - 2018/5/1

    Y1 - 2018/5/1

    N2 - We present new radio/millimeter measurements of the hot magnetic star HR5907 obtained with the VLA and ALMA interferometers. We find that HR5907 is the most radio luminous early type star in the cm-mm band among those presently known. Its multi-wavelength radio light curves are strongly variable with an amplitude that increases with radio frequency. The radio emission can be explained by the populations of the non-thermal electrons accelerated in the current sheets on the outer border of the magnetosphere of this fast-rotating magnetic star. We classify HR5907 as another member of the growing class of strongly magnetic fastrotating hot stars where the gyro-synchrotron emission mechanism efficiently operates in their magnetospheres. The new radio observations of HR5907 are combined with archival X-ray data to study the physical condition of its magnetosphere. The X-ray spectra of HR5907 show tentative evidence for the presence of non-thermal spectral component. We suggest that non-thermal X-rays originate a stellar X-ray aurora due to streams of non-thermal electrons impacting on the stellar surface. Taking advantage of the relation between the spectral indices of the X-ray power-law spectrum and the non-thermal electron energy distributions, we perform 3-D modelling of the radio emission for HR5907. The wavelength-dependent radio light curves probe magnetospheric layers at different heights above the stellar surface. A detailed comparison between simulated and observed radio light curves leads us to conclude that the stellar magnetic field of HR 5907 is likely non-dipolar, providing further indirect evidence of the complex magnetic field topology of HR5907.

    AB - We present new radio/millimeter measurements of the hot magnetic star HR5907 obtained with the VLA and ALMA interferometers. We find that HR5907 is the most radio luminous early type star in the cm-mm band among those presently known. Its multi-wavelength radio light curves are strongly variable with an amplitude that increases with radio frequency. The radio emission can be explained by the populations of the non-thermal electrons accelerated in the current sheets on the outer border of the magnetosphere of this fast-rotating magnetic star. We classify HR5907 as another member of the growing class of strongly magnetic fastrotating hot stars where the gyro-synchrotron emission mechanism efficiently operates in their magnetospheres. The new radio observations of HR5907 are combined with archival X-ray data to study the physical condition of its magnetosphere. The X-ray spectra of HR5907 show tentative evidence for the presence of non-thermal spectral component. We suggest that non-thermal X-rays originate a stellar X-ray aurora due to streams of non-thermal electrons impacting on the stellar surface. Taking advantage of the relation between the spectral indices of the X-ray power-law spectrum and the non-thermal electron energy distributions, we perform 3-D modelling of the radio emission for HR5907. The wavelength-dependent radio light curves probe magnetospheric layers at different heights above the stellar surface. A detailed comparison between simulated and observed radio light curves leads us to conclude that the stellar magnetic field of HR 5907 is likely non-dipolar, providing further indirect evidence of the complex magnetic field topology of HR5907.

    KW - Radio continuum: Stars

    KW - Stars: Chemically peculiar

    KW - Stars: Early-type

    KW - Stars: Individual: HR 5907

    KW - Stars: Magnetic field

    KW - X-rays: Stars

    UR - http://www.scopus.com/inward/record.url?scp=85043513344&partnerID=8YFLogxK

    U2 - 10.1093/mnras/sty244

    DO - 10.1093/mnras/sty244

    M3 - Article

    VL - 476

    SP - 562

    EP - 579

    JO - Monthly Notices of the Royal Astronomical Society

    T2 - Monthly Notices of the Royal Astronomical Society

    JF - Monthly Notices of the Royal Astronomical Society

    SN - 0035-8711

    IS - 1

    ER -