Scattered Light in the Hinode/EIS and SDO/AIA Instruments Measured from the 2012 Venus Transit

Young, Peter R. and Viall, Nicholeen M. (2022) Scattered Light in the Hinode/EIS and SDO/AIA Instruments Measured from the 2012 Venus Transit. The Astrophysical Journal, 938 (1). p. 27. ISSN 0004-637X

pdf.pdf - Published Version
Available under License Creative Commons Attribution 4.0.

Download (1MB) | Preview
Official URL:


Observations from the 2012 transit of Venus are used to derive empirical formulae for long- and short-range scattered light at locations on the solar disk observed by the Hinode Extreme ultraviolet Imaging Spectrometer (EIS) and the Solar Dynamics Observatory Atmospheric Imaging Assembly (AIA) instruments. Long-range scattered light comes from the entire solar disk, while short-range scattered light is considered to come from a region within 50″ of the region of interest. The formulae were derived from the Fe xii 195.12 Å emission line observed by EIS and the AIA 193 Å channel. A study of the weaker Fe xiv 274.20 Å line during the transit and a comparison of scattering in the AIA 193 Å and 304 Å channels suggests the EIS scattering formula applies to other emission lines in the EIS wavebands. Both formulae should be valid in regions of fairly uniform emission such as coronal holes and quiet Sun, but may be less accurate for faint areas close (around 100″) to bright active regions. The formula for EIS is used to estimate the scattered light component of Fe xii λ195.12 for seven on-disk coronal holes observed between 2010 and 2018. Scattered light contributions of 56%–100% are found, suggesting that these features are dominated by scattered light, consistent with earlier work of Wendeln & Landi. Emission lines from the S x and Si x ions—formed at the same temperature as Fe xii and often used to derive the first ionization potential bias from EIS data—are also expected to be dominated by scattered light in coronal holes.

Item Type: Article
Additional Information: Funding information: The authors acknowledge support from the GSFC Internal Scientist Funding Model competitive work package program “Connecting the corona to solar wind structure and magnetospheric impact using modeling and remote and in situ observations”. P.Y. also acknowledges funding from the Hinode project.
Uncontrolled Keywords: Transits, Solar extreme ultraviolet emission, Solar corona, Solar coronal lines– Venus
Subjects: F500 Astronomy
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: John Coen
Date Deposited: 13 Oct 2022 08:25
Last Modified: 13 Oct 2022 08:30

Actions (login required)

View Item View Item


Downloads per month over past year

View more statistics