Evaluation of Sunspot Areas Derived by Automated Sunspot-Detection Methods

Fuente: arXiv
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Main Author: Hanaoka, Yoichiro
Format: Preprint
Published: 2024
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author Hanaoka, Yoichiro
author_facet Hanaoka, Yoichiro
contents Sunspot-area measurements using digital images captured by two telescopes at the Mitaka campus of the National Astronomical Observatory of Japan are conducted using automated sunspot detection. A comparison between sunspot areas derived from Mitaka and those from the reference data by Mandal et al. ({\it Astron. Astrophys.} {\bf 640,} A78, 2020), who compiled a cross-calibrated daily sunspot-area catalog, revealed that the correlation coefficients between them are high (0.96--0.97), whereas the areas in the Mitaka data are 70 \%--83 \% of those of Mandal et al. The correlation is limited by the differences in observation times and detection capabilities of spots near the limb, with discrepancies in areas arising from different definitions of spot outlines. Given the high correlation and the ease of calibrating area discrepancies with a correction factor, automated sunspot detection appears promising for future sunspot-area measurements. Furthermore, we addressed the measurements of brightness deficit caused by sunspots.
format Preprint
id arxiv_https___arxiv_org_abs_2411_00415
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Evaluation of Sunspot Areas Derived by Automated Sunspot-Detection Methods
Hanaoka, Yoichiro
Solar and Stellar Astrophysics
Sunspot-area measurements using digital images captured by two telescopes at the Mitaka campus of the National Astronomical Observatory of Japan are conducted using automated sunspot detection. A comparison between sunspot areas derived from Mitaka and those from the reference data by Mandal et al. ({\it Astron. Astrophys.} {\bf 640,} A78, 2020), who compiled a cross-calibrated daily sunspot-area catalog, revealed that the correlation coefficients between them are high (0.96--0.97), whereas the areas in the Mitaka data are 70 \%--83 \% of those of Mandal et al. The correlation is limited by the differences in observation times and detection capabilities of spots near the limb, with discrepancies in areas arising from different definitions of spot outlines. Given the high correlation and the ease of calibrating area discrepancies with a correction factor, automated sunspot detection appears promising for future sunspot-area measurements. Furthermore, we addressed the measurements of brightness deficit caused by sunspots.
title Evaluation of Sunspot Areas Derived by Automated Sunspot-Detection Methods
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2411.00415