Properties of a decaying sunspot
Balthasar, H.1,
Beck, C.2,
Gömöry, P.3,
Muglach, K.4,
Puschmann, K.G.1,
Shimizu, T.5,
Verma, M.1
1 Leibniz-Institut fur Astrophysik Potsdam, An der Sternwarte 16,
14482 Potsdam, Germany
2 Instituto de Astrofisica de Canarias (IAC), via Lactea,
38205 La Laguna, Tenerife, Spain
3 Astronomical Institute of the Slovak Academy of Sciences,
05960 Tatranská Lomnica, Slovakia
4 Artep, Inc. at Goddard Space Flight Center Washington DC, USA
5 Institute of Space and Astronautical Science, Japan Aerospace Exploration
Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, 252-5210 Kanagawa, Japan
Abstract:
A small decaying sunspot was observed with the Vacuum Tower Telescope (VTT) on Tenerife
and the Japanese Hinode satellite. We obtained full Stokes scans in several wavelengths
covering different heights in the solar atmosphere. Imaging time series from Hinode and
the Solar Dynamics Observatory (SDO) complete our data sets. The spot is surrounded by
a moat flow, which persists also on that side of the spot where the penumbra already had
disappeared. Close to the spot, we find a chromospheric location with downflows of more
than 10 km/s without photospheric counterpart. The height dependence of the vertical
component of the magnetic field strength is determined in two different ways that yielded
different results in previous investigations. Such a difference still exists in our present
data, but it is not as pronounced as in the past.