Browse > Article
http://dx.doi.org/10.5140/JASS.2017.34.2.99

Variation in Solar Limb Darkening Coefficient Estimated from Solar Images Taken by SOHO and SDO  

Moon, Byeongha (Department of Earth Science Education, Chonnam National University)
Jeong, Dong-Gwon (Department of Earth Science Education, Chonnam National University)
Oh, Suyeon (Department of Earth Science Education, Chonnam National University)
Sohn, Jongdae (Korea Astronomoy and Space Science Institute)
Publication Information
Journal of Astronomy and Space Sciences / v.34, no.2, 2017 , pp. 99-103 More about this Journal
Abstract
The sun is not equally bright over the whole sphere, but rather is darkened toward the limb. This effect is well-known as limb darkening. The limb darkening coefficient is defined by the ratio of the center intensity to limb intensity. In this study, we calculate the limb darkening coefficient using the photospheric intensity estimated from solar images taken by solar and helispheric observatory (SOHO) and solar dynamics observatory (SDO). The photospheric intensity data cover almost two solar cycles from May 1996 to December 2016. The limb darkening coefficient for a size of 0.9 diameter is about 0.69 and this value is consistent with solar limb darkening. The limb darkening coefficient estimated from SOHO shows a temporal increase at solar maximum and a gradual increase since the solar minimum of 2008. The limb darkening coefficient estimated from SDO shows a constant value of about 0.65 and a decreasing trend since 2014. The increase in the coefficient reflects the effect of weakened solar activity. However, the decrease since 2014 is caused by the aging effect.
Keywords
solar limb darkening; SOHO/MDI; SDO/HMI;
Citations & Related Records
연도 인용수 순위
  • Reference
1 Athay RG, Lites BW, White OR, Brault JW, A first order analysis of variations of the limb darkening and the shapes for solar Fraunhofer lines, Sol. Phys. 24, 18-27 (1972). https://doi.org/10.1007/BF00231078   DOI
2 Moe OK, Milone EF, Limb darkening 1945-3245 A for the quiet sun from SKYLAB data, Astrophys. J. 226, 301-314 (1978). https://doi.org/10.1086/156610   DOI
3 Neckel H, On the wavelength dependency of solar limb darkening (${\lambda}{\lambda}$303 to 1099 nm), Sol. Phys. 167, 9-23 (1996). https://doi.org/10.1007/BF00146325   DOI
4 Neckel H, On the sun's absolute disk-center and mean disk intensities, its limb darkening, and its limb temperature' (${\lambda}{\lambda}$303 to 1099 nm), Sol. Phys. 212, 239-250 (2003). https://doi.org/10.1023/A:1022929504779   DOI
5 Neckel H, Analytical reference functions F(${\lambda}$) for the sun's limb darkening and its absolute continuum intensities (${\lambda}{\lambda}$303 to 1100 nm), Sol. Phys. 229, 13-33 (2005). https://doi.org/10.1007/s11207-005-4081-z   DOI
6 Neckel H, Labs D, Solar limb darkening 1986-1990 (${\lambda}{\lambda}$303 to 1099 nm), Sol. Phys. 153, 91-114 (1994). https://doi.org/10.1007/BF00712494   DOI
7 Pierce AK, Solar limb darkening in the region 10.1007/BF00712494 7793-24388, Astrophys. J. 120, 221-232 (1954). https://doi.org/10.1086/145905   DOI
8 Pierce AK, Slaughter CD, Solar limb darkening. I: ${\lambda}{\lambda}$(3033-7297), Sol. Phys. 51, 25-41 (1977). https://doi.org/10.1007/BF00240442   DOI
9 Pierce AK, McMath RR, Goldberg L, Mohler OC, Observations of solar limb darkening between 0.5 and 10.2 $\mu$, Astrophys. J. 112, 289-298 (1950). https://doi.org/10.1086/145342   DOI
10 Pierce AK, Slaughter CD, Weinberger D, Solar limb darkening in the interval 7404-24 018 ${\AA}$, II, Sol. Phys. 52, 179-189 (1977). https://doi.org/10.1007/BF00935800   DOI
11 Ramanathan AS, Study of the continuous solar spectrum in the visible range, Ann. Astrophys. 17, 18-34 (1954).
12 Rubin VC, Solar limb darkening determined from eclipse observations, Astrophys. J. 129, 812-825 (1959). https://doi.org/10.1086/146677   DOI
13 Zeilik M, Gregory SA, Introductory Astronomy and Astrophysics (Cengage Learning, Boston, 1997).
14 Sykes JB, The integral equation of limb-darkening, Mon. Not. R. Astron. Soc. 113, 198-210 (1953). https://doi.org/10.1093/mnras/113.2.198   DOI