Solar rotation and activity Solar rotation and activity from Galileo to the presentfrom Galileo to the present

Dr. David Pundak1 and Dr. Lev Pustilnik2

1Kinneret Academic College,Jordan Valley, Israel2 ICRSWC-Israel Space Weather and Cosmic Ray Center, Tel Aviv University

What do we know on Sun?1.1. The Sun is the nearest star.The Sun is the nearest star.2.2. Source of energy – nuclear synthesis of hydrogen to Source of energy – nuclear synthesis of hydrogen to

helium in the solar core.helium in the solar core.3.3. Origin of the Sun – collapse of the proto-solar cloud Origin of the Sun – collapse of the proto-solar cloud

of gas and dust into a star. Remnants of this of gas and dust into a star. Remnants of this collapse – solar system = numerous planets and collapse – solar system = numerous planets and asteroids co-rotated in the ecliptic plane.asteroids co-rotated in the ecliptic plane.

4.4. Expected solar rotation must be coaxial to global rotation of Expected solar rotation must be coaxial to global rotation of the solar system. Possible way to study – observation of the solar system. Possible way to study – observation of markers = sunspots.markers = sunspots.

5.5. Solar activity – additional energy release in solar Solar activity – additional energy release in solar atmosphere in the form of coronal heating, solar wind and atmosphere in the form of coronal heating, solar wind and solar flares. Origin of solar activity caused by emergence of solar flares. Origin of solar activity caused by emergence of magnetic flux from the deeper convective zone that formed magnetic flux from the deeper convective zone that formed solar active regions and sunspots.solar active regions and sunspots.

Three levels of Solar rotation project

(ASTROTOP Vision) Primary Notions.

Quality experiments:“YES-NO” based on simple

astronomical examples.Simple description-model

“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.

Solar rotation1.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.

•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.

I. Introductory level – discovery of solar rotation

Apollon Telescope-

-Eudoxos, -Greece

Sea of GalileeObservatory-Israel

SOHO- Space

SolarObservatory

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 observationsConclusion:

Sun rotates with period P24-25 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

Change of longitude and altiude of sunspots on the Sun

Longitude = 13.66*t - 22.3

Altitude= -0.4132*t + 13.9

-40.0

-20.0

0.0

20.0

40.0

60.0

80.0

0 1 2 3 4 5 6 7days

de

gre

es

longitudealtitude(longitude) ליניארי(altitude) ליניארי

Solar rotation2.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.

1. 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

II - Intermediate level:Are sunspot location, sunspot rotation and number of sunspots

constants or they change with time?

II - Intermediate levelII - Intermediate level: : Are sunspot location, sunspot rotation Are sunspot location, sunspot rotation and number of sunspots constants or they change with timeand 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 (!).

Sunspot's longitude, rotation period, sunspot number during 1996-2006

5

15

25

35

45

55

65

1994 1996 1998 2000 2002 2004 2006 2008

year

Altiu

de&

SN

/2.

23

24

25

26

27

28

29

Ro

tatio

n P

eri

od

(sid

eri

c)

Sunspot Longitude

sunspot number/2

Period_sider

Poly. (Period_sider)

Poly. (Sunspot Longitude)

Poly. (sunspot number/2)Rotation period

Sunspot Longitude

Sunspot number(SN)/2

Solar rotation3.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.

III. Advance Level: Solar activity during hundreds years

Does 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

Sunspot number 1700-2004

020406080

100120140160180200

1700 1722 1744 1766 1788 1810 1832 1854 1876 1898 1920 1942 1964 1986time (year)

su

nsp

ot

nu

mb

er

.

ConclusionConclusion: 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)

Sunspot's longitude, rotation period, sunspot number during 1996-2006

5

15

25

35

45

55

65

1994 1996 1998 2000 2002 2004 2006 2008

year

Altiu

de&S

N/2.

23

24

25

26

27

28

29

Rota

tion

Perio

d (s

ider

ic)

Sunspot Longitude

sunspot number/2

Period_sider

Poly. (Period_sider)

Poly. (Sunspot Longitude)

Poly. (sunspot number/2)Rotation period

Sunspot Longitude

Sunspot number(SN)/2

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 thesame altitudes and the same rate as today. Changes of solar rotation during the past 400years are absent or negligible.

Is solar activity permanent phenomena or this plodder has holidays from time to time?

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

Sunspot number during 1600-1700 years (Maunder Minimum)

0

10

20

30

40

50

60

1600 1610 1620 1630 1640 1650 1660 1670 1680 1690 1700 1710 1720 1730year

Su

nsp

ots

nu

mb

er

ConclusionsConclusions::• Period of solar rotation is about 25-27 days and changes with altitude Period of solar rotation is about 25-27 days and changes with altitude

of the spots (faster on equator and slower at the poles).of the spots (faster on equator and slower at the poles).• Sunspots location, rotation and number, change with about 11-years Sunspots location, rotation and number, change with about 11-years

period.period.• Amplitude and period of 11-year sunspots cycle change essentially Amplitude and period of 11-year sunspots cycle change essentially

during hundreds years. during hundreds years. • Sometimes sunspot disappear along tens up to hundred years with Sometimes sunspot disappear along tens up to hundred years with

drastically sequences for Earth climate.drastically sequences for Earth climate.• Solar rotation is much more stable and does not shows detectable Solar rotation is much more stable and does not shows detectable

change from Galileo observations (400 year ago).change from Galileo observations (400 year ago).

For Future:For Future:• Continuation of this research will lay on regular observations of Continuation of this research will lay on regular observations of

sunspots with SkyWatch telescopes.sunspots with SkyWatch telescopes.• Working with databases on solar activity and climate from ancient Working with databases on solar activity and climate from ancient

times.times.

Project “Solar rotation and activity” as part of Program “ASTROTOP”

........................

Is our Civilisation sensitiveto Space W eather

Solar activity andSpace W eather

S olar rota tion and ac tiv ityfrom G alileo up tod ay

Burth, life and deadof one yellow dw arf

and his friends

..........................ASTROTOP – program of ASTROTOP – program of ““Blossom of Sciences” for Blossom of Sciences” for

students of high school, motivated students of high school, motivated to research in Astronomy.to research in Astronomy.

ASTROTOP includes tens projects, ASTROTOP includes tens projects, join scientists and tens teachers join scientists and tens teachers

and hundreds students-participants.and hundreds students-participants.

ASTROTOP based on more then ASTROTOP based on more then 40 prepared projects with databases, 40 prepared projects with databases,

instructions for teacher-supervisor and instructions for teacher-supervisor and for student-researcher.for student-researcher.

ASTROTOP is open for international ASTROTOP is open for international cooperation and adaptation of our cooperation and adaptation of our

method to European educational worldmethod to European educational world