Sun-as-a-star Study of an X-class Solar Flare with Spectroscopic Observations of CHASE
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arXiv
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| Autori principali: | , , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| _version_ | 1866917613830930432 |
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| author | Ma, Y. L. Lao, Q. H. Cheng, X. Wang, B. T. Zhao, Z. H. Rao, S. H. Li, C. Ding, M. D. |
| author_facet | Ma, Y. L. Lao, Q. H. Cheng, X. Wang, B. T. Zhao, Z. H. Rao, S. H. Li, C. Ding, M. D. |
| contents | Sun-as-a-star spectroscopic characteristics of solar flares can be used as a benchmark for the detection and analyses of stellar flares. Here, we study the Sun-as-a-star properties of an X1.0 solar flare using high-resolution spectroscopic data obtained by the Chinese $\mathrm{H} α$ Solar Explorer (CHASE). A noise reduction algorithm based on discrete Fourier transformation is first employed to enhance the signal-to-noise ratio of the space-integral $\mathrm{H} α$ spectrum with a focus on its typical characteristics. For the flare of interest, we find that the average $\mathrm{H} α$ profile displays a strong emission at the line center and an obvious line broadening. It also presents a clear red asymmetry, corresponding to a redshift velocity of around $50 \ \mathrm{km \ s^{-1}}$ that slightly decreases with time, consistent with previous results. Furthermore, we study how the size of the space-integral region affects the characteristics of the flare Sun-as-a-star $\mathrm{H} α$ profile. It is found that although the redshift velocity calculated from the $\mathrm{H} α$ profile remains unchanged, the detectability of the characteristics weakens as the space-integral region becomes large. An upper limit for the size of the target region where the red asymmetry is detectable is estimated. It is also found that the intensity in $\mathrm{H} α$ profiles, measured by the equivalent widths of the spectra, are significantly underestimated if the $\mathrm{H} α$ spectra are further averaged in the time domain. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2403_09011 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Sun-as-a-star Study of an X-class Solar Flare with Spectroscopic Observations of CHASE Ma, Y. L. Lao, Q. H. Cheng, X. Wang, B. T. Zhao, Z. H. Rao, S. H. Li, C. Ding, M. D. Solar and Stellar Astrophysics Sun-as-a-star spectroscopic characteristics of solar flares can be used as a benchmark for the detection and analyses of stellar flares. Here, we study the Sun-as-a-star properties of an X1.0 solar flare using high-resolution spectroscopic data obtained by the Chinese $\mathrm{H} α$ Solar Explorer (CHASE). A noise reduction algorithm based on discrete Fourier transformation is first employed to enhance the signal-to-noise ratio of the space-integral $\mathrm{H} α$ spectrum with a focus on its typical characteristics. For the flare of interest, we find that the average $\mathrm{H} α$ profile displays a strong emission at the line center and an obvious line broadening. It also presents a clear red asymmetry, corresponding to a redshift velocity of around $50 \ \mathrm{km \ s^{-1}}$ that slightly decreases with time, consistent with previous results. Furthermore, we study how the size of the space-integral region affects the characteristics of the flare Sun-as-a-star $\mathrm{H} α$ profile. It is found that although the redshift velocity calculated from the $\mathrm{H} α$ profile remains unchanged, the detectability of the characteristics weakens as the space-integral region becomes large. An upper limit for the size of the target region where the red asymmetry is detectable is estimated. It is also found that the intensity in $\mathrm{H} α$ profiles, measured by the equivalent widths of the spectra, are significantly underestimated if the $\mathrm{H} α$ spectra are further averaged in the time domain. |
| title | Sun-as-a-star Study of an X-class Solar Flare with Spectroscopic Observations of CHASE |
| topic | Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2403.09011 |