Elemental Abundances in the Solar Corona as Measured by the X-ray Solar Monitor Onboard Chandrayaan-1

Narendranath, S.; Sreekumar, P.; Alha, L.; Sankarasubramanian, K.; Huovelin, J.; Athiray, P. S.

doi:10.1007/s11207-013-0410-9

Cited by 22 publications

(21 citation statements)

References 19 publications

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“…The X-ray Solar Monitor on Chandrayaan-1 is similar to the SMART-1 XSM except for a reduction in the aperture size to accommodate a wider dynamic range in the expected counts. This instrument measured the X-ray spectrum in the range of approximately 1.8 -20 keV from several X-ray flares during the nine month mission life from 28 November 2008 to 29 August 2009 and the results were presented in Narendranath et al (2014). Narendranath et al (2014).…”

Section: Chandrayaan-1 Xsmmentioning

confidence: 99%

“…Stellar coronae also exhibit this effect (Drake, Laming, and Widing, 1997;Laming and Drake, 1999;Garcia-Alvarez et al, 2004) as well as the inverse termed as inverse-FIP (IFIP) effect (see Laming, 2015, for a review). Studies in the past such as those by Feldman (1992), Fludra and Schmelz (1999), Phillips et al (2003), Feldman and Laming (2006), Sylwester et al (2010), Sylwester et al (2012), Schmelz et al (2012), Narendranath et al (2014), Dennis et al (2015) and Moore et al (2018) to name a few, suggest that this deviation or FIP bias is not the same for all elements. The range of reported values in the past, also suggests that FIP bias values may be nominally stable but possibly vary with solar cycle phase (Brooks et al, 2017) and spatial location on the Sun.…”

Section: Introductionmentioning

confidence: 96%

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Coronal Elemental Abundance: New Results from Soft X-Ray Spectroscopy of the Sun

et al. 2020

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Elemental abundances in the solar corona are known to be different from those observed in the solar photosphere. The ratio of coronal to photospheric abundance shows a dependence on the first ionisation potential (FIP) of the element. We estimate FIP bias from direct measurements of elemental abundances from soft X-ray spectra using data from multiple space missions covering a range of solar activity levels. This comprehensive analysis shows clear evidence for a decrease in FIP bias around maximum intensity of the X-ray flare with coronal abundances briefly tending to photospheric values and a slow recovery as the flare decays. The departure from coronal abundances are larger for the low FIP elements Ca, Fe and Si than for S which have a mid FIP value. These changes in the degree of fractionation might provide inputs to model wave propagation through the chromosphere during flares.

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Section: Chandrayaan-1 Xsmmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Coronal Elemental Abundance: New Results from Soft X-Ray Spectroscopy of the Sun

et al. 2020

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“…Elemental abundances during solar flares have been reported to be coronal or intermediate between the coronal and photospheric values (Sterling et al 1993;Sylwester et al 1998;Fludra & Schmelz 1999;Phillips & Dennis 2012;Narendranath et al 2014;Sylwester et al 2015;Dennis et al 2015). However, it was recently realized that the abundance pattern is different from coronal abundances, in that the boundary between low-FIP and high-FIP elements is about 7 eV (Dennis et al 2015), significantly less than ∼10 eV that is normally observed for solar coronae or solar energetic particles.…”

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confidence: 97%

Inverse First Ionization Potential Effects in Giant Solar Flares Found from Earth X-Ray Albedo with Suzaku/XIS

Katsuda

Ohno

Mori

et al. 2020

ApJ

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We report X-ray spectroscopic results for four giant solar flares occurred on 2005 September 7 (X17.0), 2005 September 8 (X5.4), 2005 September 9 (X6.2), and 2006 December 5 (X9.0), obtained from Earth albedo data with the X-ray imaging spectrometer (XIS) onboard Suzaku. The good energy resolution of the XIS (FWHM∼100 eV) enables us to separate a number of line-like features and detect the underlying continuum emission. These features include Si Heα, Si Lyα, S Heα, S Lyα, Ar Heα, and Ca Heα originating from solar flares as well as fluorescent Ar Kα and Ar Kβ from the Earth atmosphere. Absolute elemental abundances (X/H) averaged over the four flares are obtained to be ∼2.0 (Ca), ∼0.7 (Si), ∼0.3 (S), and ∼0.9 (Ar) at around flare peaks. This abundance pattern is similar to those of active stars' coronae showing inverse first ionization potential (i-FIP) effects, i.e., elemental abundances decrease with decreasing FIP with a turnover at the low end of FIP. The abundances are almost constant during the flares, with an exception of Si which increases by a factor of ∼2 in the decay phase. The evolution of the Si abundance is consistent with a picture that the i-FIP plasma originates from the chromosphere evaporation and then mixes with the surrounding low-FIP biased materials. Flare-to-flare abundance varied by a factor of 2, agreeing with past observations of solar flares. Finally, we emphasize that Earth albedo data acquired by X-ray astronomy satellites like Suzaku and XRISM can significantly contribute to studies of solar physics.

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“…From the same mission, Narendranath et al 22 reported elemental abundances in the Solar Corona using the Chandrayaan-1 X-ray Solar monitor. The authors presented abundances of the rock-forming elements, Al, Ca, Mg and Si (as well as Na) and provided a detailed description of analytical techniques, including the derivation of XRF line uxes and the conversion to elemental abundances.…”

Section: Hand-held Mobile On-line Xrf Techniques and Planetary Explmentioning

confidence: 99%

2015 Atomic Spectrometry Update – a review of advances in X-ray fluorescence spectrometry and their applications

West¹,

Ellis

Potts

et al. 2015

J. Anal. At. Spectrom.

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Elemental Abundances in the Solar Corona as Measured by the X-ray Solar Monitor Onboard Chandrayaan-1

Cited by 22 publications

References 19 publications

Coronal Elemental Abundance: New Results from Soft X-Ray Spectroscopy of the Sun

Coronal Elemental Abundance: New Results from Soft X-Ray Spectroscopy of the Sun

Inverse First Ionization Potential Effects in Giant Solar Flares Found from Earth X-Ray Albedo with Suzaku/XIS

2015 Atomic Spectrometry Update – a review of advances in X-ray fluorescence spectrometry and their applications

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