Temperature of quiet Sun small scale brightenings observed by EUI on board Solar Orbiter: Evidence for a cooler component

A., Dolliou,; Parenti, S.; Auchère, F.; Bocchialini, K.; Pelouze, Gabriel; Antolin, Patrick; Berghmans, David; Harra, L. K.; Long, David M.; Schühle, U.; Kraaikamp, E.; Stegen, K.; Gissot, S.; Cuadrado, R. Aznar; Buchlin, É.; Mierla, M.; Teriaca, L.; Zhukov, A. N.

doi:10.1051/0004-6361/202244914

Cited by 10 publications

(2 citation statements)

References 64 publications

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“…Compared with the DEM results in Berghmans et al (2021), who reported that EUI brightenings can reach coronal temperature, our cases are more likely to have a lower temperature. A similar result can be found in Dolliou, A. et al (2023), who conducted a time-lag analysis of EUI brightenings. This measures the time delays between the light curves of different AIA channels.…”

Section: Discussionsupporting

confidence: 82%

Imaging and spectroscopic observations of extreme-ultraviolet brightenings using EUI and SPICE on board Solar Orbiter

Huang,

Teriaca,

Cuadrado

et al. 2023

Preprint

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Context. The smallest extreme-ultraviolet (EUV) brightening events that were detected so far, called campfires, have recently been uncovered by the High Resolution EUV telescope (HRI EUV ), which is part of the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter. HRI EUV has a broad bandpass centered at 17.4 nm that is dominated by Fe ix and Fe x emission at about 1 MK. Aims. We study the thermal properties of EUI brightening events by simultaneously observing their responses at different wavelengths using spectral data from the Spectral Imaging of the Coronal Environment (SPICE) also on board Solar Orbiter and imaging data from EUI. Methods. We studied three EUI brightenings that were identified in HRI EUV data that lie within the small areas covered by the slit of the SPICE EUV spectrometer. We obtained the line intensities of the spectral profiles by Gaussian fitting. These diagnostics were used to study the evolution of the EUI brightenings over time at the different line-formation temperatures. Results. We find that (i) the detection of these EUI brightenings is at the limit of the SPICE capabilities. They could not have been independently identified in the data without the aid of HRI EUV observations. (ii) Two of these EUI brightenings with longer lifetimes are observed up to Ne viii temperatures (0.6 MK). (iii) All of the events are detectable in O vi (0.3 MK), and the two longer-lived events are also detected in other transition region (TR) lines. (iv) In one case, we observe two peaks in the intensity light curve of the TR lines that are separated by 2.7 min for C iii and 1.2 min for O vi. The Ne viii intensity shows a single peak between the two peak times of the TR line intensity. Conclusions. Spectral data from SPICE allow us to follow the thermal properties of EUI brightenings. Our results indicate that at least some EUI brightenings barely reach coronal temperatures.

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Section: Discussionsupporting

confidence: 82%

Imaging and spectroscopic observations of extreme-ultraviolet brightenings using EUI and SPICE on board Solar Orbiter

Huang,

Teriaca,

Cuadrado

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Compared with the DEM results in Berghmans et al (2021), who reported that EUI brightenings can reach coronal temperature, our cases are more likely to have a lower temperature. A similar result can be found in Dolliou et al (2023), who conducted a time-lag analysis of EUI brightenings. This measures the time delays between the light curves of different AIA channels.…”

Section: Discussionsupporting

confidence: 82%

Imaging and spectroscopic observations of extreme-ultraviolet brightenings using EUI and SPICE on board Solar Orbiter

Huang¹,

Teriaca²,

Cuadrado³

2023

A&A

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Context. The smallest extreme-ultraviolet (EUV) brightening events that were detected so far, called campfires, have recently been uncovered by the High Resolution EUV telescope (HRIEUV), which is part of the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter. HRIEUV has a broad bandpass centered at 17.4 nm that is dominated by Fe IX and Fe X emission at about 1 MK. Aims. We study the thermal properties of EUI brightening events by simultaneously observing their responses at different wavelengths using spectral data from the Spectral Imaging of the Coronal Environment (SPICE) also on board Solar Orbiter and imaging data from EUI. Methods. We studied three EUI brightenings that were identified in HRIEUV data that lie within the small areas covered by the slit of the SPICE EUV spectrometer. We obtained the line intensities of the spectral profiles by Gaussian fitting. These diagnostics were used to study the evolution of the EUI brightenings over time at the different line-formation temperatures. Results. We find that (i) the detection of these EUI brightenings is at the limit of the SPICE capabilities. They could not have been independently identified in the data without the aid of HRIEUV observations. (ii) Two of these EUI brightenings with longer lifetimes are observed up to Ne VIII temperatures (0.6 MK). (iii) All of the events are detectable in O VI (0.3 MK), and the two longer-lived events are also detected in other transition region (TR) lines. (iv) In one case, we observe two peaks in the intensity light curve of the TR lines that are separated by 2.7 min for C III and 1.2 min for O VI. The Ne VIII intensity shows a single peak between the two peak times of the TR line intensity. Conclusions. Spectral data from SPICE allow us to follow the thermal properties of EUI brightenings. Our results indicate that at least some EUI brightenings barely reach coronal temperatures.

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First perihelion of EUI on the Solar Orbiter mission

Berghmans¹,

Antolin²,

F.³

et al. 2023

A&A

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Context. The Extreme Ultraviolet Imager (EUI) on board Solar Orbiter consists of three telescopes: the two High Resolution Imagers, in EUV (HRIEUV) and in Lyman-α (HRILya), and the Full Sun Imager (FSI). Solar Orbiter/EUI started its Nominal Mission Phase on 2021 November 27. Aims. Our aim is to present the EUI images from the largest scales in the extended corona off-limb down to the smallest features at the base of the corona and chromosphere. EUI is therefore a key instrument for the connection science that is at the heart of the Solar Orbiter mission science goals. Methods. The highest resolution on the Sun is achieved when Solar Orbiter passes through the perihelion part of its orbit. On 2022 March 26, Solar Orbiter reached, for the first time, a distance to the Sun close to 0.3 au. No other coronal EUV imager has been this close to the Sun. Results. We review the EUI data sets obtained during the period 2022 March–April, when Solar Orbiter quickly moved from alignment with the Earth (2022 March 6), to perihelion (2022 March 26), to quadrature with the Earth (2022 March 29). We highlight the first observational results in these unique data sets and we report on the in-flight instrument performance. Conclusions. EUI has obtained the highest resolution images ever of the solar corona in the quiet Sun and polar coronal holes. Several active regions were imaged at unprecedented cadences and sequence durations. We identify in this paper a broad range of features that require deeper studies. Both FSI and HRIEUV operated at design specifications, but HRILya suffered from performance issues near perihelion. We conclude by emphasizing the EUI open data policy and encouraging further detailed analysis of the events highlighted in this paper.

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Temperature of quiet Sun small scale brightenings observed by EUI on board Solar Orbiter: Evidence for a cooler component

Cited by 10 publications

References 64 publications

Imaging and spectroscopic observations of extreme-ultraviolet brightenings using EUI and SPICE on board Solar Orbiter

Imaging and spectroscopic observations of extreme-ultraviolet brightenings using EUI and SPICE on board Solar Orbiter

Imaging and spectroscopic observations of extreme-ultraviolet brightenings using EUI and SPICE on board Solar Orbiter

First perihelion of EUI on the Solar Orbiter mission

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