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X-Raying the Dark Side of Venus - Scatter from Venus Magnetotail?
- Publication Year :
- 2016
-
Abstract
- This work analyzes the X-ray, EUV and UV emission apparently coming from the Earth-facing (dark) side of Venus as observed with Hinode/XRT and SDO/AIA during a transit across the solar disk occurred in 2012. We have measured significant X-Ray, EUV and UV flux from Venus dark side. As a check we have also analyzed a Mercury transit across the solar disk, observed with Hinode/XRT in 2006. We have used the latest version of the Hinode/XRT Point Spread Function (PSF) to deconvolve Venus and Mercury X-ray images, in order to remove possible instrumental scattering. Even after deconvolution, the flux from Venus shadow remains significant while in the case of Mercury it becomes negligible. Since stray-light contamination affects the XRT Ti-poly filter data from the Venus transit in 2012, we performed the same analysis with XRT Al-mesh filter data, which is not affected by the light leak. Even the Al-mesh filter data show residual flux. We have also found significant EUV (304 A, 193 A, 335 A) and UV (1700 A) flux in Venus shadow, as measured with SDO/AIA. The EUV emission from Venus dark side is reduced when appropriate deconvolution methods are applied; the emission remains significant, however. The light curves of the average flux of the shadow in the X-ray, EUV, and UV bands appear different as Venus crosses the solar disk, but in any of them the flux is, at any time, approximately proportional to the average flux in a ring surrounding Venus, and therefore proportional to the average flux of the solar regions around Venus obscuring disk line of sight. The proportionality factor depends on the band. This phenomenon has no clear origin; we suggest it may be due to scatter occurring in the very long magnetotail of Venus.<br />This paper has been accepted in The Astrophysical Journal
- Subjects :
- Earth and Planetary Astrophysics (astro-ph.EP)
Physics
Point spread function
planets and satellites: atmospheres
Line-of-sight
010504 meteorology & atmospheric sciences
biology
Extreme ultraviolet lithography
Gamma ray
planets and satellites: individual (Venus)
FOS: Physical sciences
Flux
Astronomy and Astrophysics
Venus
Astrophysics
Light curve
biology.organism_classification
01 natural sciences
Settore FIS/05 - Astronomia E Astrofisica
Space and Planetary Science
0103 physical sciences
Transit (astronomy)
010303 astronomy & astrophysics
0105 earth and related environmental sciences
Astrophysics - Earth and Planetary Astrophysics
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....cea78b04bad08948081ae8e2ae27400b