Astrophysical: Sunspots

  • Publication
    On the Energy Balance of Solar Active Regions
    Ground-based observations of the sunspot irradiance deficit Ψ and the excess by facular regions in the period 1989 June 3-15 are analyzed using photometric...
  • Publication
    On the fine structure of sunspot penumbrae. I. A quantitative comparison of two semiempirical models with implications for the Evershed effect
    Sunspot penumbrae exhibit prominent fine structure. Different interpretations of spectropolarimetric observations suggest different, sometimes contradictory...
  • Publication
    On the fine structure of sunspot penumbrae. II. The nature of the Evershed flow
    We investigate the fine structure of the sunspot penumbra by means of a model that allows for a flux tube in horizontal pressure balance with the magnetic...
  • Publication
    On the fine structure of sunspot penumbrae. III. The vertical extension of penumbral filaments
    In this paper we study the fine structure of the penumbra as inferred from the uncombed model (flux tube embedded in a magnetic surrounding) when applied to...
  • Publication
    On the initial orientation of emerging active regions
    The initial orientation of 74 active regions (ARs) as measured in high resolution pictures. As previous works by the author (Garcia de la Rosa, 1984) suggest a...
  • Publication
    On the Moat-Penumbra Relation
    Proper motions in a sunspot group with a δ-configuration and close to the solar disk center have been studied by employing local correlation tracking techniques...
  • Publication
    On the origin of reverse polarity patches found by Hinode in sunspot penumbrae
    Context: The topology of penumbral magnetic fields is poorly known. The satellite Hinode has recently revealed penumbral structures of a magnetic polarity that...
  • Publication
    On the relation between the intensities of bright features and the local background in sunspot umbrae
    A photometric study of umbral bright features (umbral dots, clusters of umbral dots, bright grains of light bridges) in sunspots is presented. It is based on...
  • Publication
    On the Source of Propagating Slow Magnetoacoustic Waves in Sunspots
    Recent high-resolution observations of sunspot oscillations using simultaneously operated ground- and space-based telescopes reveal the intrinsic connection...