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Solar rotation and activity from Galileo to the present

Solar rotation and activity from Galileo to the present. Dr. David Pundak 1 and Dr. Lev Pustilnik 2 1 Kinneret Academic College,Jordan Valley, Israel 2 ICRSWC-Israel Space Weather and Cosmic Ray Center, Tel Aviv University. What do we know on Sun?. The Sun is the nearest star.

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Solar rotation and activity from Galileo to the present

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  1. Solar rotation and activity from Galileo to the present Dr. David Pundak1 and Dr. Lev Pustilnik2 1Kinneret Academic College,Jordan Valley, Israel 2 ICRSWC-Israel Space Weather and Cosmic Ray Center, Tel Aviv University

  2. What do we know on Sun? • The Sun is the nearest star. • Source of energy – nuclear synthesis of hydrogen to helium in the solar core. • Origin of the Sun – collapse of the proto-solar cloud of gas and dust into a star. Remnants of this collapse – solar system = numerous planets and asteroids co-rotated in the ecliptic plane. • Expected solar rotation must be coaxial to global rotation of the solar system. Possible way to study – observation of markers = sunspots. • Solar activity – additional energy release in solar atmosphere in the form of coronal heating, solar wind and solar flares. Origin of solar activity caused by emergence of magnetic flux from the deeper convective zone that formed solar active regions and sunspots.

  3. Primary Notions. Quality experiments:“YES-NO” based on simple astronomical examples. Simple description-model Three levels ofSolar rotation project(ASTROTOP Vision) “First Principles” Laws. Simple dependences on 5-10 measurements. Simple models and relations. Advanced understanding of laws of nature Multi-parameter astronomical experiment based on real astronomical project with real observations (10%-30%) and Internet databases (70%-90%). Multifactor models and relations.

  4. Solar rotation Level I (introductory) – discovery of the solar rotation and inclination of the solar axis based on 1 year of sunspot observation with SkyWatch solar telescopes and with telescopes from the Sea of Galilee Observatory.

  5. I. Introductory level – discovery of solar rotation • Observational data – set of solar images with sunspots (7-14 days) from the SkyWatch telescope, the Sea of Galilee Observatory with solar filter and from the SOHO space observatory. • Apollon • Telescope- • Eudoxos, • Greece Sea of Galilee Observatory -Israel SOHO - Space Solar Observatory

  6. Estimation of solar rotation period • Longitude dependence on time gives estimation of the solar rotation period P. *** We need 4- 7 daily observations • Altitude variation during year (changed during year) gives estimation of inclination of solar rotation axis: i=7. *** We need 4 seasons of 4-7 daily observations Conclusion: Sun rotates with period P24-25 days around axis inclined on 7 to ecliptic Longitude=(13.66 degrees/day)* t(days) Period of full solar rotation on 360 degrees is: P0=360 deg/13.66 deg/day= =26.3542 days Correction on Earth orbital rotation in the same direction in the solar system give Psolar rot=P0(1-P0/365)=24.4 days

  7. Solar rotation Level II (intermediate) – discovery of the 11-year solar cycle and differences in solar rotation using SOHO and SkyWatch observations and databases of solar active observations during the past tens years.

  8. II - Intermediate level: Are sunspot location, sunspot rotation and number of sunspots constants or they change with time? • Data: 10 years of SOHO full disc images database (from 1996 to 2006 years) http://solar.to.astro.it/DataSummary/index.html http://soi.stanford.edu/production/int_gifs.html 2. Studies: • Predominant spot’s location as function of time • Period as function of time/location on the Sun • Number of sunspots as function of time

  9. II - Intermediate level: Are sunspot location, sunspot rotation and number of sunspots constants or they change with time? • Results of data analysis: Conclusion:Sunspot position, sunspot number and sunspot rotation change during 1996-2006 drastically. During maximum of sunspot number (2000-2002) they are localized near solar equator and rotate faster then in another time – differential rotation (!).

  10. Solar rotation Level III (advanced) – discovery of the instabilities in the past hundred years in the solar cycle and studying the solar rotation stability through hundreds years using Galileo’s observations in 1614 and sunspot data from 1614 to the present day.

  11. III. Advance Level: Solar activity during hundreds yearsDoes solar activity change randomly or is it a regular activity? • Data: Sunspot Number (SN) from 1700 up to present time (2005) from database:ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/SUNSPOT_NUMBERS/YEARLY.PLT Conclusion: Sunspot number changes regularly in time – oscillates from SN=0 up to SN=1200 during an 11 year period. Both period and amplitude of this cycle are very unstable (amplitude from 0 to 200, period from 9 years to 14 years)

  12. Were sunspot rotation and localization in time during Galileo’s time the same as today?Altitude (Galileo) = 25 degRotation Period (Galileo) =29.9 day Sunspots’ rotation during Galileo’s time Conclusion: sunspot rotation during Galileo’s time had the same altitudes and the same rate as today. Changes of solar rotation during the past 400 years are absent or negligible.

  13. Is solar activity permanent phenomena or this plodder has holidays from time to time? • Data : solar activity in 1600 –1700 indigo.ie/~hforde/ei6cpb/ sunspots/ANCIENT_DATA/earlyssn.txt • Absence of sunspots during tens years – Maunder Minimum – pause in solar activity – nature of this shutdown is unknown. • Similar pauses had places during last centuries • This pause influence on the Earth Climate drastically (“small ice periods”) • When will be next pause? • How long it will continue? • Can we predict the next pause?

  14. Conclusions: • Period of solar rotation is about 25-27 days and changes with altitude of the spots (faster on equator and slower at the poles). • Sunspots location, rotation and number, change with about 11-years period. • Amplitude and period of 11-year sunspots cycle change essentially during hundreds years. • Sometimes sunspot disappear along tens up to hundred years with drastically sequences for Earth climate. • Solar rotation is much more stable and does not shows detectable change from Galileo observations (400 year ago). For Future: • Continuation of this research will lay on regular observations of sunspots with SkyWatch telescopes. • Working with databases on solar activity and climate from ancient times.

  15. Project “Solar rotation and activity” as part of Program “ASTROTOP” ASTROTOP – program of “Blossom of Sciences” for students of high school, motivated to research in Astronomy. ASTROTOP includes tens projects, join scientists and tens teachers and hundreds students-participants. ASTROTOP based on more then 40 prepared projects with databases, instructions for teacher-supervisor and for student-researcher. ASTROTOP is open for international cooperation and adaptation of our method to European educational world

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