Issue |
A&A
Volume 395, Number 3, December I 2002
|
|
---|---|---|
Page(s) | L51 - L54 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361:20021531 | |
Published online | 18 November 2002 |
Letter to the Editor
Evidence for short-period acoustic waves in the solar atmosphere
1
Universitäts-Sternwarte, Geismarlandstraße 11, 37083 Göttingen, Germany
2
Institut für Geophysik, Astrophysik und Meteorologie, Universitätsplatz 5, 8010 Graz, Austria
Corresponding author: M. Wunnenberg, wunnenbe@uni-sw.gwdg.de
Received:
27
September
2002
Accepted:
17
October
2002
Short-period acoustic waves are thought to supply the energy for the radiative losses of the non-magnetic chromosphere of the Sun and, in general, of late-type stars.
Here, we present evidence for the existence of waves in the solar atmosphere
with periods in the range of 50 s 100 s. Two-dimensional time sequences
with a cadence of 25 s were obtained from quiet Sun disk center in
Fe i 5434 Å. The observations were performed with the
“Göttingen” Fabry-Perot spectrometer in the Vacuum Tower Telescope
at the Observatorio del Teide/Tenerife. They are subjected to speckle
reconstruction and to a wavelet analysis. The atmospheric ranges forming
the velocity signals are narrowed by linear combinations of Doppler maps
from wavelengths near line center. The power in the short-period range is
concentrated above intergranular spaces. We estimate an acoustic flux into
the chromosphere of approximately 3
erg cm-2 s-1,
as needed for the chromospheric radiative losses.
Key words: waves / Sun: photosphere / Sun: chromosphere
© ESO, 2002
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