UCL  IRIS
Institutional Research Information Service
UCL Logo
Please report any queries concerning the funding data shown on the profile page to:

http://www.ucl.ac.uk/finance/secure/research/post_award
Please report any queries concerning the student data shown on the profile page to:

Email: portico-services@ucl.ac.uk

Help Desk: http://www.ucl.ac.uk/ras/portico/helpdesk
Publication Detail
Is the Jovian auroral H-3(+) emission polarised?
  • Publication Type:
    Journal article
  • Publication Sub Type:
    Article
  • Authors:
    Barthelemy M, Lystrup MB, Menager H, Miller S, Lilensten J
  • Publisher:
    EDP SCIENCES S A
  • Publication date:
    06/2011
  • Journal:
    ASTRON ASTROPHYS
  • Volume:
    530
  • Print ISSN:
    0004-6361
  • Language:
    EN
  • Keywords:
    polarization, molecular data, planets and satellites: aurorae, planets and satellites: individual: Jupiter, LINEAR-POLARIZATION, ION, ATMOSPHERES, IMPACT, WINDS
  • Addresses:
    Barthelemy, M
    UJF CNRS
    Inst Planetol & Astrophys Grenoble
    F-38041
    Grenoble
    9
    France
Abstract
Context. Measurement of linear polarisation in Earth's thermospheric oxygen red line can be a useful observable quantity for characterising conditions in the upper atmosphere; therefore, polarimetry measurements are extended to other planets. Since FUV emissions are not observable from the ground, the best candidates for Jupiter auroral emissions are H-3(+) infrared lines near 4 mu m. This ion is created after a chemical process in the Jovian upper atmosphere. Thus the anisotropy responsible of the polarisation cannot be the particle impact as in the Earth case.Aims. The goal of this study is to detect polarisation of H-3(+) emissions from Jupiter's aurora.Methods. Measurements of the H-3(+) emissions from Jupiter's southern auroral oval were performed at the UK Infrared Telescope using the UIST-IRPOL spectro-polarimeter, with the instrument slit positioned perpendicular to Jupiter's rotation axis. Data were processed by dividing the slit into 24 bins. Stokes parameters (u, q and v), polarisation degree and direction were extracted for each bin and debiased.Results. More than 5 bins show polarisation with a confidence level above 3 sigma. Polarisation degrees up to 7% are detected. Assuming the auroral intensity is constant during the 8 waveplate positions exposure time, i.e. around 10 min, strong circular polarisation is present, with an absolute value of the Stokes v parameter up to 0.35. Conclusions. This study shows that polarisation is detectable in the Jovian infrared auroras, but new measurements are needed to be able to use it to characterise the ionospheric environment. At present, it is not possible to propose a mechanism to explain this polarisation owing to the lack of theoretical work and laboratory experiments concerning the polarisation of H-3(+).
Publication data is maintained in RPS. Visit https://rps.ucl.ac.uk
 More search options
UCL Authors
Dept of Science & Technology Studies
University College London - Gower Street - London - WC1E 6BT Tel:+44 (0)20 7679 2000

© UCL 1999–2011

Search by