Number of Sunspot Groups and Individual Sunspots Recorded by Tevel for the Period 1816–1836 in the Dalton Minimum

2021 ◽  
Vol 922 (1) ◽  
pp. 58
Author(s):  
V. M. S. Carrasco
Keyword(s):  
Solar Cycle ◽  
Sunspot Number ◽  
Sunspot Group ◽  
Maunder Minimum ◽  
The Other ◽  
Solar Cycles ◽  
Group Number ◽  
The One ◽  
Dalton Minimum ◽  
Sunspot Groups

Abstract Cornelis Tevel made sunspot observations during the period 1816–1836, including the Dalton Minimum. In this work, the first revision of these observations since Wolf incorporated them into his database is presented. On the one hand, the number of individual sunspots from Tevel’s drawings was counted. This is of special interest for the sunspot number reconstruction because this kind of information is not as common in historical sunspot records as the number of groups. Thus, Tevel could be considered for the future reconstruction of the sunspot number index. On the other hand, the number of groups counted according to modern sunspot group classifications finding significant misinterpretations with the number of groups assigned to Tevel in the existing databases. Tevel was a relevant sunspot observer in the Dalton Minimum. In fact, he was the observer with the highest number of groups observed in Solar Cycles 6 and 7 according to the existing sunspot group number databases. According to the raw group number recount in this work, the maximum amplitudes for Solar Cycles 6 and 7 are, respectively, 27% and 7% lower than those previously determined. Moreover, Solar Cycle 6 is the weakest solar cycle since the Maunder Minimum after applying these new counts. Group counts from Tevel’s observations were compared with those from relevant contemporary astronomers, demonstrating that Schwabe and Tevel systematically recorded a higher number of groups than Flaugergues and Derfflinger. In addition, sunspot areas and positions recorded by Tevel should be used with caution for scientific purposes.

scholarly journals Reanalyses of the sunspot observations of Fogelius and Siverus: Two “Long-Term” observers during the Maunder Minimum

2020 ◽  
Author(s):  
Hisashi Hayakawa ◽  
Tomoya Iju ◽  
Shoma Uneme ◽  
Bruno P Besser ◽  
Shunsuke Kosaka ◽  
...  
Keyword(s):  
Sunspot Group ◽  
Maunder Minimum ◽  
Solar Cycles ◽  
Observational Period ◽  
The Core ◽  
Cycle Amplitude ◽  
Group Number ◽  
The One ◽  
Sunspot Groups

Abstract The solar activity during the Maunder Minimum (MM; 1645–1715) has been considered significantly different from the one captured in modern observations, in terms of sunspot group number and sunspot positions, whereas its actual amplitudes and distributions is still under active discussions. In its core period (1650/1660–1700), Martin Fogelius and Henrich Siverus have formed significant long-term series in the existing databases with numerous spotless days, as the 13th and 7th most active observers before the end of the MM. In this study, we have analysed their original archival records, revised their data, have removed significant contaminations of the apparent ‘spotless days’ in the existing databases, and cast caveats on the potential underestimation of the solar-cycle amplitude in the core MM. Still, they reported at best one sunspot group throughout their observational period and confirm the significant suppressed the solar cycles during the MM, which is also supported from the contemporary observations of Hook and Willoughby. Based on the revised data, we have also derived positions of notable sunspot groups, which Siverus recorded in 1671 (≈ N7.5° ± 2.5°), in comparison with those of Cassini's drawings (≈ N10° ± 1°). Their coincidence in position and chronology in corrected dates indicates these sunspot groups were probably the same recurrent active region (AR) and its significantly long lifespan (≥ 35 days) even during the MM.

Sunspot and Group Number: Recent advances from historical data

2018 ◽  
Vol 14 (A30) ◽  
pp. 156-159 ◽  
Author(s):  
Frédéric Clette ◽  
José M. Vaquero ◽  
María Cruz Gallego ◽  
Laure Lefèvre
Keyword(s):  
Sunspot Number ◽  
Maunder Minimum ◽  
Current Data ◽  
Activity Level ◽  
Historical Evidence ◽  
The Earth ◽  
Earth Environment ◽  
Group Number ◽  
Dalton Minimum

AbstractDue to its unique 400-year duration, the sunspot number is a central reference for understanding the long-term evolution of solar activity and its influence on the Earth environment and climate. Here, we outline current data recovery work. For the sunspot number, we find historical evidence of a disruption in the source observers occurring in 1947–48. For the sunpot group number, recent data confirm the clear southern predominance of sunspots during the Maunder Minimum, while the umbra-penumbra ratio is similar to other epochs. For the Dalton minimum, newly recovered historical observations confirm a higher activity level than in a true Grand Minimum.

scholarly journals Solar Wind Helium Abundance Heralds Solar Cycle Onset

2021 ◽  
Author(s):  
Benjamin L Alterman ◽  
Justin C Kasper ◽  
Robert J Leamon ◽  
Scott W McIntosh
Keyword(s):  
Solar Wind ◽  
Solar Cycle ◽  
Sunspot Number ◽  
Cycle Length ◽  
Phase Lag ◽  
Helium Abundance ◽  
Solar Cycles ◽  
Wind Speeds ◽  
Solar Wind Acceleration ◽  
Solar Cycle Length

Abstract We study the solar wind helium-to-hydrogen abundance's ( A He ) relationship to solar cycle onset. Using OMNI/Lo data, we show that A He increases prior to sunspot number (SSN) minima. We also identify a rapid depletion and recovery in A He that occurs directly prior to cycle onset. This A He Shutoff happens at approximately the same time across solar wind speeds ( v sw ) and the time between successive A He shutoffs is typically on the order of the corresponding solar cycle length. In contrast to A He 's v sw -dependent phase lag with respect to SSN (Alterman and Kasper, 2019), A He Shutoff's concurrence across v sw likely implies it is independent of solar wind acceleration and driven by a mechanism near or below the photosphere. Using Brightpoint (BP) measurements to provide context, we infer that this shutoff is likely related to the overlap of adjacent solar cycles and the equatorial flux cancelation of the older, extended solar cycle during solar minima.

ESTABLISHING SOLAR ACTIVITY TREND FOR SOLAR CYCLES 21 – 24

2021 ◽  
Vol 44 ◽  
pp. 100-106
Author(s):  
A.K. Singh ◽  
◽  
A. Bhargawa ◽  
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Sunspot Number ◽  
Cosmic Ray ◽  
Occurrence Rate ◽  
The Sun ◽  
Solar Cycles ◽  
Lyman Alpha ◽  
Rate Versus ◽  
Alpha Index

Solar-terrestrial environment is manifested primarily by the physical conditions of solar interior, solar atmosphere and eruptive solar plasma. Each parameter gives unique information about the Sun and its activity according to its defined characteristics. Hence the variability of solar parameters is of interest from the point of view of plasma dynamics on the Sun and in the interplanetary space as well as for the solar-terrestrial physics. In this study, we have analysed various solar transients and parameters to establish the recent trends of solar activity during solar cycles 21, 22, 23 and 24. The correlation coefficients of linear regression of F10.7 cm index, Lyman alpha index, Mg II index, cosmic ray intensity, number of M & X class flares and coronal mass ejections (CMEs) occurrence rate versus sunspot number was examined for last four solar cycles. A running cross-correlation method has been used to study the momentary relationship among the above mentioned solar activity parameters. Solar cycle 21 witnessed the highest value of correlation for F10.7 cm index, Lyman alpha index and number of M-class and X-class flares versus sunspot number among all the considered solar cycles which were 0.979, 0.935 and 0.964 respectively. Solar cycle 22 recorded the highest correlation in case of Mg II index, Ap index and CMEs occurrence rate versus sunspot number among all the considered solar cycles (0.964, 0.384 and 0.972 respectively). Solar cycle 23 and 24 did not witness any highest correlation compared to solar cycle 21 and 22. Further the record values (highest value compared to other solar three cycles) of each solar activity parameters for each of the four solar cycles have been studied. Here solar cycle 24 has no record text at all, this simply indicating that this cycle was a weakest cycle compared to the three previous ones. We have concluded that in every domain solar 24 was weaker to its three predecessors.

scholarly journals Potential energy stored by planets and grand minima events

2011 ◽  
Vol 7 (S286) ◽  
pp. 410-413
Author(s):  
Rodolfo G. Cionco
Keyword(s):  
Solar Cycle ◽  
Solar System ◽  
Potential Energy ◽  
Internal Structure ◽  
Temporal Evolution ◽  
Maunder Minimum ◽  
The Sun ◽  
Dalton Minimum ◽  
Putative Mechanism ◽  
Grand Minima

AbstractRecently, Wolff & Patrone (2010), have developed a simple but very interesting model by which the movement of the Sun around the barycentre of the Solar system could create potential energy that could be released by flows pre-existing inside the Sun. The authors claim that it is the first mechanism showing how planetary movements can modify internal structure in the Sun that can be related to solar cycle. In this work we point out limitations of mentioned mechanism (which is based on interchange arguments), which could be inapplicable to a real star. Then, we calculate the temporal evolution of potential energy stored in zones of Sun's interior in which the potential energy could be most efficiently stored taking into account detailed barycentric Sun dynamics. We show strong variations of potential energy related to Maunder Minimum, Dalton Minimum and the maximum of Cycle 22, around 1990. We discuss briefly possible implications of this putative mechanism to solar cycle specially Grand Minima events.

scholarly journals In-depth survey of sunspot and active region catalogs

2010 ◽  
Vol 6 (S273) ◽  
pp. 221-225 ◽  
Author(s):  
Laure Lefèvre ◽  
Frédéric Clette ◽  
Tunde Baranyi
Keyword(s):  
Active Region ◽  
Sunspot Group ◽  
Solar Cycles ◽  
Time Intervals ◽  
Long Time ◽  
Comprehensive Survey ◽  
Central Database ◽  
Index Time Series ◽  
Activity Indices ◽  
Sunspot Groups

AbstractWhen consulting detailed photospheric catalogs for solar activity studies spanning long time intervals, solar physicists face multiple limitations in the existing catalogs: finite or fragmented time coverage, limited time overlap between catalogs and even more importantly, a mismatch in contents and conventions. In view of a study of new sunspot-based activity indices, we have conducted a comprehensive survey of existing catalogs.In a first approach, we illustrate how the information from parallel catalogs can be merged to form a much more comprehensive record of sunspot groups. For this, we use the unique Debrecen Photoheliographic Data (DPD), which is already a composite of several ground observatories and SOHO data, and the USAF/Mount Wilson catalog from the Solar Optical Observing Network (SOON). We also describe our semi-interactive cross-identification method, which was needed to match the non-overlapping solar active region nomenclature, the most critical and subtle step when working with multiple catalogs. This effort, focused here first on the last two solar cycles, should lead to a better central database collecting all available sunspot group parameters to address future solar cycle studies beyond the traditional sunspot index time series Ri.

scholarly journals Gradual onset of the Maunder Minimum revealed by high-precision carbon-14 analyses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hiroko Miyahara ◽  
Fuyuki Tokanai ◽  
Toru Moriya ◽  
Mirei Takeyama ◽  
Hirohisa Sakurai ◽  
...  
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
High Precision ◽  
Crop Yields ◽  
Maunder Minimum ◽  
The Sun ◽  
Solar Cycles ◽  
Precision Data ◽  
Carbon 14 ◽  
Grand Minimum

AbstractThe Sun exhibits centennial-scale activity variations and sometimes encounters grand solar minimum when solar activity becomes extremely weak and sunspots disappear for several decades. Such an extreme weakening of solar activity could cause severe climate, causing massive reductions in crop yields in some regions. During the past decade, the Sun’s activity has tended to decline, raising concerns that the Sun might be heading for the next grand minimum. However, we still have an underdeveloped understanding of solar dynamo mechanisms and hence precise prediction of near-future solar activity is not attained. Here we show that the 11-year solar cycles were significantly lengthened before the onset of the Maunder Minimum (1645–1715 CE) based on unprecedentedly high-precision data of carbon-14 content in tree rings. It implies that flow speed in the convection zone is an essential parameter to determine long-term solar activity variations. We find that a 16 year-long cycle had occurred three solar cycles before the onset of prolonged sunspot disappearance, suggesting a longer-than-expected preparatory period for the grand minimum. As the Sun has shown a tendency of cycle lengthening since Solar Cycle 23 (1996–2008 CE), the behavior of Solar Cycle 25 can be critically important to the later solar activity.

scholarly journals Comparison of the shape and temporal evolution of even and odd solar cycles

2020 ◽  
Vol 636 ◽  
pp. A11
Author(s):  
Jouni Takalo ◽  
Kalevi Mursula
Keyword(s):  
Sunspot Group ◽  
Temporal Evolution ◽  
Sunspot Area ◽  
Distribution Analysis ◽  
Solar Cycles ◽  
Sunspot Numbers ◽  
Group Data ◽  
Odd Cycles ◽  
Skewness And Kurtosis ◽  
Sunspot Groups

Aims. We study the difference in the shape of solar cycles for even and odd cycles using the Wolf sunspot numbers and group sunspot numbers of solar cycles 1−23. We furthermore analyse the data of sunspot area sizes for even and odd cycles SC12−SC23 and sunspot group data for even and odd cycles SC8−SC23 to compare the temporal evolution of even and odd cycles. Methods. We applied the principal component analysis (PCA) to sunspot cycle data and studied the first two components, which describe the average cycle shape and cycle asymmetry. We used a distribution analysis to analyse the temporal evolution of the even and odd cycles and determined the skewness and kurtosis for even and odd cycles of sunspot group data. Results. The PCA confirms the existence of the Gnevyshev gap (GG) for solar cycles at about 40% from the start of the cycle. The temporal evolution of sunspot area data for even cycles shows that the GG exists at least at the 95% confidence level for all sizes of sunspots. On the other hand, the GG is shorter and statistically insignificant for the odd cycles of aerial sunspot data. Furthermore, the analysis of sunspot area sizes for even and odd cycles of SC12−SC23 shows that the greatest difference is at 4.2−4.6 years, where even cycles have a far smaller total area than odd cycles. The average area of the individual sunspots of even cycles is also smaller in this interval. The statistical analysis of the temporal evolution shows that northern sunspot groups maximise earlier than southern groups for even cycles, but are concurrent for odd cycles. Furthermore, the temporal distributions of odd cycles are slightly more leptokurtic than distributions of even cycles. The skewnesses are 0.37 and 0.49 and the kurtoses 2.79 and 2.94 for even and odd cycles, respectively. The correlation coefficient between skewness and kurtosis for even cycles is 0.69, and for odd cycles, it is 0.90. Conclusions. The separate PCAs for even and odd sunspot cycles show that odd cycles are more inhomogeneous than even cycles, especially in GSN data. Even cycles, however, have two anomalous cycles: SC4 and SC6. The variation in the shape of the early sunspot cycles suggests that there are too few and/or inaccurate measurements before SC8. According to the analysis of the sunspot area size data, the GG is more distinct in even than odd cycles. This may be partly due to sunspot groups maximizing earlier in the northern than in the southern hemisphere for even cycles. We also present another Waldmeier-type rule, that is, we find a correlation between skewness and kurtosis of the sunspot group cycles.

scholarly journals Sounding stellar cycles with Kepler – III. Comparative analysis of chromospheric, photometric, and asteroseismic variability

2019 ◽  
Vol 485 (4) ◽  
pp. 5096-5104 ◽  
Author(s):  
C Karoff ◽  
T S Metcalfe ◽  
B T Montet ◽  
N E Jannsen ◽  
A R G Santos ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Physical Mechanism ◽  
Sparse Sampling ◽  
The Other ◽  
Energy Output ◽  
The Sun ◽  
Cyclic Variability ◽  
Kepler Mission ◽  
Chromospheric Emission ◽  
The One

ABSTRACT By combining ground-based spectrographic observations of variability in the chromospheric emission from Sun-like stars with the variability seen in their eigenmode frequencies, it is possible to relate the changes observed at the surfaces of these stars to the changes taking place in the interior. By further comparing this variability to changes in the relative flux from the stars, one can obtain an expression for how these activity indicators relate to the energy output from the stars. Such studies become very pertinent when the variability can be related to stellar cycles as they can then be used to improve our understanding of the solar cycle and its effect on the energy output from the Sun. Here, we present observations of chromospheric emission in 20 Sun-like stars obtained over the course of the nominal 4 yr Kepler mission. Even though 4 yr is too short to detect stellar equivalents of the 11 yr solar cycle, observations from the Kepler mission can still be used to analyse the variability of the different activity indicators thereby obtaining information of the physical mechanism generating the variability. The analysis reveals no strong correlation between the different activity indicators, except in very few cases. We suggest that this is due to the sparse sampling of our ground-based observations on the one hand and that we are likely not tracing cyclic variability on the other hand. We also discuss how to improve the situation.

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