Issue |
A&A
Volume 411, Number 3, December I 2003
|
|
---|---|---|
Page(s) | L497 - L500 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361:20031618 | |
Published online | 17 November 2003 |
Letter to the Editor
The flares associated with the abnormal rotation rates of the bipolar sunspots: Reconnection probably below the surface
1
Indian Institute of Astrophysics, Bangalore-560034, India
2
Indian Institute of Astrophysics, Kodaikanal-624103, India
Corresponding author: K. M. Hiremath, hiremath@iiap.ernet.in
Received:
26
September
2003
Accepted:
14
October
2003
We use the observations of Kodaikanal observatory white light
pictures to study the association between the rotation
rates of the bipolar sunspots and triggering of the flares.
For the years 1969-1974, we compute daily rotation rates of the leading
and the following spots of the bipolar sunspot groups during their life
span. We find that either leading or following or both of the bipolar
spot groups which
have abnormal rotation rates during the course of their evolution are strongly
associated with the occurrence of flares in the later stage of their life span.
Other important findings are: (i) the abnormal rotation rates and the flares
occur during the of their life span of the spot group and,
(ii) abnormal rotation
rate of about
/day is required for triggering
the flares. The strong relation between the occurrence of abnormal rotation
rates of the sunspot groups and the occurrence of the flares enabled us to
estimate the probable region of depth of reconnection below the solar surface.
Key words: bipolar sunspots / abnormal rotation rates / flares / flux tubes
© ESO, 2003
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