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A solar cycle lengthwise series of solar diameter measurements

Published online by Cambridge University Press:  26 February 2010

J. L. Penna ,
A. H. Andrei ,
S. C. Boscardin ,
E. Reis Neto  and
V. A. d'Ávila
J. L. Penna
Affiliation:
Observatório Nacional/MCT, R. Gal. Jose Cristino 77, Rio de Janeiro, Brazil email: oat1@on.br
A. H. Andrei
Affiliation:
Observatório Nacional/MCT, R. Gal. Jose Cristino 77, Rio de Janeiro, Brazil email: oat1@on.br Obs. do Valongo/UFRJ-BR, Rio de Janeiro, Brazil
S. C. Boscardin
Affiliation:
Observatório Nacional/MCT, R. Gal. Jose Cristino 77, Rio de Janeiro, Brazil email: oat1@on.br
E. Reis Neto
Affiliation:
Observatório Nacional/MCT, R. Gal. Jose Cristino 77, Rio de Janeiro, Brazil email: oat1@on.br
V. A. d'Ávila
Affiliation:
Observatório Nacional/MCT, R. Gal. Jose Cristino 77, Rio de Janeiro, Brazil email: oat1@on.br UERJ-BR, Rio de Janeiro, Brazil
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Abstract

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The measurements of the solar photospheric diameter rank among the most difficult astronomic observations. Reasons for this are the fuzzy definition of the limb, the SNR excess, and the adverse daytime seeing condition. As a consequence there are very few lengthy and consistent time series of such measurements. Using modern techniques, just the series from the IAG/USP and from Calern/OCA span more than one solar cycle. The Rio de Janeiro Group observations started in 1997, and therefore in 2008 one complete solar cycle time span can be analyzed. The series shares common principles of observation and analysis with the ones afore mentioned, and it is complementary on time to them. The distinctive features are the larger number of individual points and the improved precision. The series contains about 25,000 single observations, evenly distributed on a day-by-day basis. The typical error of a single observation is half an arc-second, enabling us to investigate variations at the expected level of tens of arc-second on a weekly basis. These features prompted to develop a new methodology for the investigation of the heliophysical scenarios leading to the observed variations, both on time and on heliolatitude. The algorithms rely on running averages and time shifts to derive the correlation and statistical incertitude for the comparison of the long term and major episodes variations of the solar diameter against activity markers. The results bring support to the correlation between the diameter variation and the solar activity, but evidentiating two different regimens for the long term trend and the major solar events.

Keywords

Sun: photospherefundamental parametersactivityinstrumentation: photometersmethods: statistical
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 5 , Symposium S264: Solar and Stellar Variability: Impact on Earth and Planets , August 2009 , pp. 49 - 54
Copyright
Copyright © International Astronomical Union 2010

References

Andrei, A. H., Penna, J. L., Reis Neto, E., D’Ávila, V. A., de Almeida, W. G., & Jilinski, E. G. 2002, What are the astrolabe observations of the Sun measuring?, First Annual Meeting of the R2S3, Calern, France.Google Scholar
Andrei, A. H., Boscardin, S. C., Chollet, F., Delmas, C., Golbasi, O., Jilinski, E. G., Kili, H., Laclare, F., Morand, F., Penna, J. L., & Reis Neto, E. 2004, Comparison of CCD astrolabe multi-site solar diameter observations, Astronomy & Astrophysics, 427, 717–723.CrossRefGoogle Scholar
Andrei, A. H., Boscardin, S. C., Reis Neto, E., Penna, J. L., & D’Ávila, V. A. 2006, Variations of the solar radius in solar cycle 23, SCOSTEP-CAWSES Meeting, 1, 43–44.Google Scholar
Boscardin, S. C. 2004, Diameter observations analysis in the solar activity context, MSc Thesis, UFRJ, Observatorio do Valongo.Google Scholar
Boscardin, S. C., Reis Neto, E., Penna, J. L., Papa, A. R. R., Andrei, A. H., & D’Ávila, V. A. 2009, Observed variations of the solar photospheric diameter, 2009, IAU Symposium 264, Solar and Stellar Variability – Impact on Earth and Planets.CrossRefGoogle Scholar
Damé, L., Brun, J.-F., Cugnet, D., Derrien, M., Leroy, C., Meftah, M., Meissonnier, M., & Porteneuve, J. 2000, A solar diameter metrology measurement: the PICCARD microsatellite program, ICSO 2000.Google Scholar
Durney, B. R. & Roxburgh, I. W. 1971, Inhomogeneous convection and the equatorial acceleration of the Sun, Solar Physics, 16, 3–11.CrossRefGoogle Scholar
Hirzberger, J., Vazquez, M., Bonet, J. A., Hansmeier, A., & Sobotka, M. 1997, The series of solar granulation inages. I. Differences between small and large granules in quiet regions, The Astrophysical Journal, 480, 406–419.CrossRefGoogle Scholar
Jilinski, E. G., Puliaev, S. P., Penna, J. K., Andrei, A. H., Sinceac, V., Chollet, F., & Delmas, C. 1998, Solar diameter observations with the astrolabe at Observatório Nacional Rio de Janeiro, Astronomy & Astrophysics Supplement Series, 130, 317–321.CrossRefGoogle Scholar
Mursula, K. 2005, Sun and Heliosphere, University of Oulu.Google Scholar
Reis Neto, E., Andrei, A. H., Pennal, J. L., Jilinski, E. G., & Puliaev, S. P. 2003, Observed variations of the solar diameter in 1998–2000, Solar Physics, 212, 7–16.CrossRefGoogle Scholar
Roudier, Th. & Reardon, K. 1998, Variations of the solar granulation over the cycle: previous results and future observations, Synoptic Solar Physics, 140, 455–466.Google Scholar
Sofia, S., Basu, S., Demarque, P., Linghuai, L., & Thuiller, G. 2006, The nonhomologous nature of solar diameter variations, Astrophysical Journal, 632, 439.Google Scholar