Evidence for a larger Sun with a slower rotation during the seventeenth century

Ribes, E.; Ribes, Jean-Paul; Barthalot, Raymonde

doi:10.1038/326052a0

Cited by 73 publications

(28 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the Gleissberg cycle, the published observations disagree with each other. In one modern investigation, the maximum diameter was judged to have occurred around the time of maximum surface activity (Parkinson et al 1980;Parkinson 1983); in other investigations, the diameter increased around the time of minimum surface activity (Dunham et al 1980;Gilliland 1981;Ribes et al 1987), while further studies have found no significant diameter change at all (Shapiro 1980;Morrison et al 1988;Toulmonde 1997). The historical results suggest only that .…”

Section: Virial Theoremmentioning

confidence: 99%

A Virial Theorem Investigation of Magnetic Variations in the Sun

Stothers

2006

ApJ

View full text Add to dashboard Cite

The magnetic virial theorem is applied here to a long-standing astrophysical problem, namely, the sign of the Sun's radius change during the solar activity cycle. The solar radius is theoretically found to decrease around the time of maximum magnetic field strength, in agreement with the best available observational evidence. This theoretical prediction, although simply based, instills some confidence by explicitly satisfying the conservation of total energy.

show abstract

Section: Virial Theoremmentioning

confidence: 99%

A Virial Theorem Investigation of Magnetic Variations in the Sun

Stothers

2006

ApJ

View full text Add to dashboard Cite

show abstract

“…The analysis of these historical radius measurements shows that the solar diameter was systematically larger during the years 1660-1720, as already pointed out by Ribes et al (1987Ribes et al ( , 1993. Obviously, these measurements remain open to criticism (see for instance O'Dell & Van Helden 1987).…”

Section: Early Measurements Of the Solar Diametermentioning

confidence: 52%

On the relation between total irradiance and radius variations

Pap

Rozelot²,

Godier³

et al. 2001

A&A

View full text Add to dashboard Cite

Abstract. We use Singular Spectrum Analysis (SSA) to analyze total solar irradiance variations and CERGA radius measurements. Total solar irradiance has been monitored from space for more than two decades, whilst ground-based radius measurements are available as a coherent time series from 1975. We compare these indicators to try to understand the origin of energy production inside the Sun. One of the main objectives was to assess the reality of the observed variations of the Sun's radius by distinguishing the signal from the noise. Two approaches were used: one using SSA on ground-based data averaged over 90 days, in order to smooth the signal (especially over periods when no data were obtained, mainly in winter time); the second repeats the analysis on individual measurements corrected by reporting data to the zenith. As expected, the level of noise is higher in the first case and the reconstructed noise level, which is large, indicates the difficulty in ascertaining the solar origin in the apparent variability of the solar radius. It is shown from the reconstructed components that the main variation in amplitude (over 930 days) is pronounced during the first part of the measurements and seems to disappear after 1988. There is also a variation with a periodicity of 1380 days, of lower amplitude than that of the shorter component. In both cases, these variations disappear during the rising portion of cycle 23. The first reconstructed component shows that total irradiance varies in parallel with the solar cycle, being higher during maximum activity conditions. The reconstructed radius trend indicates that the solar radius was higher during the minimum of solar cycle 21, but its decrease with the rising activity of cycle 23 is less obvious. The observed value of the solar radius increased by about 0.11 arcsec from the maximum of cycle 21 to the minimum between cycles 21 and 22. Most importantly, we report a long-term radius variation which increased from the maximum of cycle 21 to minimum by about 0.015%, while a smaller decrease (around 0.01%) is seen from the minimum of cycle 21 to the maximum of cycle 22. This study indicates need for measurements of the degree of the radius changes taken from space, together with total irradiance measurements to establish the phase relation between these two quantities.

show abstract

“…The solar image was too small to observe other than relatively large sunspots, but enough to estimate the coordinates of sunspots by measuring the contact times of the sunspot and the solar limb (Ribes, Ribes, and Barthalot, 1987). Some pictures and the applied method of measurements of sunspot coordinates by Picard and de La Hire suggest that the observed sunspots were large.…”

Section: The Minimum As Described In Terms Of Sunspot Number and Freqmentioning

confidence: 98%

The Maunder Minimum and the Sun as the Possible Source of Particles Creating Increased Abundance of the 14C Carbon Isotope

Rek¹

2009

Sol Phys

View full text Add to dashboard Cite

The Maunder Minimum was the time during the second part of the 17th century, nominally from 1645 to 1717 AD, when unusually low numbers of sunspots were observed. On the basis of numerous recorded observations of auroras in the early 18th century, the end of the Minimum could be regarded as around 1700, but details of sunspot observations by Jan Heweliusz (Heweliusz, Machina Coelestis, 1679), John Flamsteed and Philippe de La Hire in 1684 allow us to interpret the Maunder Minimum as the period without a significant cessation of activity. This Minimum was also recognized in 14 C data from trees which grew during the second part of 17th century.The variation in the production rate of radioactive carbon isotope 14 C is due to modulation of the cosmic ray flux producing it by the changing level of solar activity and solar magnetic flux. Stronger magnetic fields in the solar wind make it more difficult for cosmic rays to reach the Earth, causing a drop in the production rate of 14 C. However, more detailed analyses of 14 C data indicate that the highest isotope abundances do not occur at the time of sunspot minima, as would be expected on the basis of modulation of the cosmic ray flux by the solar magnetic field, but two years after the sunspot number maximum. This time difference (or phase delay) can be accounted for if in fact there are both solar and non-solar cosmic ray contributions. Solar flares could also contribute high-energy particles and produce 14 C and are generally not most frequent at the time of the highest sunspot numbers in the cycle. Solar flares, most frequent about two years after the sunspot maximum, could be the main source of increased 14 C isotope abundance. This idea changes established earlier relations between sunspot number of this time regarded as low and increased abundance of 14 C isotope, and allows us to interpret the Maunder Minimum as a botanical or statistical effect.

show abstract

Evidence for a larger Sun with a slower rotation during the seventeenth century

Cited by 73 publications

References 16 publications

A Virial Theorem Investigation of Magnetic Variations in the Sun

A Virial Theorem Investigation of Magnetic Variations in the Sun

On the relation between total irradiance and radius variations

The Maunder Minimum and the Sun as the Possible Source of Particles Creating Increased Abundance of the 14C Carbon Isotope

Contact Info

Product

Resources

About