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Return of bi-polar group

santanu basu's picture
santanu basu
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Joined: 2013-05-26

I am observing sunspot regularly. On the first week of February 2014, there was a giant bi-polar group(which also naked eye). And from 1st January to 14th January there was also a large bi-polar group emerged again on the east of solar disc. I think that was the same giant bi-polar return to near side of the sun, which was existed from 27th Jan to 9th Feb. There is some testimony of my thought.

1) On 1st Jan there was an entry of a bi-polar group of spot.

2) This spot moved throughout at the equatorial zone.

3) On 14th Jan its went away.

4) At the equator the rotation of sun is about approx 25 days. Its takes 12.5 days to half rotate.

5) After 13 days i.e on 27th Jan the group returned as a spot near equator.

6) It is also a giant bi-polar group.

7) It also moved near about the equator.

8) After 13days on 9th Feb its turn to the far side of the sun.

So, Its is definitely the return of the group is observed.

Return of sunspots
HRHA's picture
HRHA
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Joined: 2010-10-15

Hi Santanu,

It seems large sunspots may take months to decay and so return again on the solar disk facing Earth.  Spaceweather.com has noted this with the AR 1967 group (active region), which yesterday February 25, 2014 created an X-class (X 4.9) flare as AR 1990 (reclassification using the Boulder classification scheme).  

"Active sunspot AR1990 (formerly AR1967) poses a threat for X-classsolar flares. Credit: SDO/HMI"   http://spaceweather.com/

It's good to review the Zurich classification of sunspot groups:  http://www.aavso.org/zurich-classification-system-sunspot-groups   and recognize that groups (active-regions) spend more time in the decay cycle than in the beginning classifications.  The AR 1967 last go-around of the sun was either an E or F class group, and may now as AR 1990, be classified as an H or I class group (Zurich classification scheme).  

Rodney

AAVSO 49 Bay State Rd. Cambridge, MA 02138 aavso@aavso.org 617-354-0484