Circular polarization of the CA II H and K lines in solar quiet and active regions

Bibcode
1990ApJ...361L..81M
DOI
10.1086/185832
Martinez Pillet, V.; Garcia Lopez, R. J.; del Toro Iniesta, J. C.; Rebolo, R.; Vazquez, M.; Beckman, J. E.; Char, S.
Bibliographical reference

Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X), vol. 361, Oct. 1, 1990, p. L81-L85. Research supported by CICYT.

Advertised on:
10
1990
Journal
Astrophysical Journal
Number of authors
7
IAC number of authors
3
Citations
27
Refereed citations
20
Description
A representative set of profiles is presented for the Ca II H resonace line in Stokes V and I, for the quiet sun, plages, sunspot umbrae, and a flare, as well as one example of the Ca II K line in a sunspot penumbra. The degree of polarization is highest in the spots and zero in the quiet sun, within error limits. The V profile asymmetries are, however, highest in the flare. The spectra of the Ca II K line are used to obtain a linear relation between V(lambda) and -dI/d(lambda) and a value for B(parallel) of 820 + or - 40 G using the weak-field approximation.
Type
Refereed
Solar activity
Solar flares
Sunspots

It may interest you

  • Refereed
    Characterisation at Cryogenic Temperatures of an Attenuator for an Application of Astrophysical Instrumentation with MKIDs
    The use of non-cryogenic certified commercial electronics for cryogenic applications may be attractive due to their cost and availability, but it also carries risks related to reliability, performance and thermal compatibility. The decision to use commercial components that are not certified for cryogenics instead of components specifically
    Rodríguez Ramos L.F. et al.

    Advertised on:

    12
    2024
  • Refereed
    The return of FarNet-II: Generation of solar far-side magnetograms from helioseismic data
    Context. The far-side activity of the Sun can be inferred by interpreting the near-side wave field using local helioseismic techniques. However, detections are limited to strongly active regions because signal-to-noise ratio of the data is low. Recently, we developed the FarNet and FarNet-II neural networks to improve the identification of active
    Broock, E. G. et al.

    Advertised on:

    12
    2024
    Bibcode
    2024A&A...692A.182B
    Citations
    0
  • Refereed
    Non-local thermodynamic equilibrium inversions of the Si I 10827 Å spectral line
    Inferring the coupling of different atmospheric layers requires observing spectral lines sensitive to the atmospheric parameters, particularly the magnetic field vector, at various heights. The best way to tackle this goal is to perform multi-line observations simultaneously. For instance, the new version of the Gregor Infrared Spectrograph
    Quintero Noda, C. et al.

    Advertised on:

    12
    2024
    Bibcode
    2024A&A...692A.169Q
    Citations
    0