Planetary protection in the extreme environments of low-mass stars

A. A. Vidotto, M. Jardine, J. Morin, J. -F. Donati, P. Lang, A. J. B. Russell

    Research output: Chapter in Book/Report/Conference proceedingChapter


    Recent results showed that the magnetic' field of M-dwarf RIM) stars, currently the main targets in searches for terrestrial planets is very different from the solar one, both in topology as well as in intensity. In particular, the magnetised environment surrounding a planet orbiting in the habitable zone (HZ) of dAl stars can differ substantially to the one encountered around the Earth. These extreme magnetic fields can compress planetary magnetospheres to such an extent that a significant fraction of the planet's atmosphere may be exposed to erosion by the stellar wind. Using observed surface magnetic amps for a sample of 15 (DJ stars, we investigate the minimum degree of planetary magnetospheric compression caused by the intense stellar magnetic fields. We show that hypothetical Earth-like planets with similar terrestrial magnetisation (-1 G) orbiting at the inner (outer) edge of the HZ of these stars would present magnetospheres that extend at most up to 6.1 (11.7) planetary radii. To be able to sustain an Earth-sized magnetosphere, the terrestrial planet would either need to orbit significantly farther out than the traditional limits of the HZ: or else, if it were orbiting within the life-bearing, region. it would require a minimum magnetic field ranging from a few G to up to a few thousand G.
    Original languageEnglish
    Title of host publicationMagnetic fields throughout stellar evolution
    Subtitle of host publicationProceedings of the international Astronomical Union Symposia and Colloquia
    EditorsPascal Petit, Moira Jardine, Hendrik Spruit
    Place of PublicationCambridge
    PublisherCambridge University Press
    Number of pages2
    ISBN (Print)9781107044982
    Publication statusPublished - 24 Aug 2014

    Publication series

    NameIAU Symposium Proceedings Series


    • stars: magnetic fields
    • stars: planetary systems
    • stars: rotation. astrobiologs


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