NuSTAR observations of the quietest Sun
Abstract
Observing X-rays (above a few keV) from the Sun provides a direct insight into energy release (heating and/or particle acceleration) in the solar atmosphere. Targeting the faintest X-ray emission allows the study of the smallest flares and eruption, and crucially their contribution to heating the solar atmosphere. NuSTAR is an astrophysics telescope that uses directly focusing X-rays optics to detect weak X-rays from the Sun. We have observed the Sun many times since the start of solar pointings in Sep 2014 through to our latest observations in 2019. See http://ianan.github.io/nsovr/ for an overview. During the current solar minimum, when the Sun is devoid of active regions and presenting the very quietest levels of activity, NuSTAR has targeted the Sun several times. We have detected X-rays from a variety of sources: large diffuse sources, steady compact sources, brief flares/brightenings and small eruptions. The NuSTAR X-ray images of these weak sources are related to features seen at other wavelengths, such as in softer X-rays with Hinode/XRT and EUV with SDO/AIA. Crucially, NuSTAR's imaging spectroscopy allows us to obtain and fit the X-ray spectrum from these small events determining their thermal (and potentially non-thermal) properties. We will present some of the latest solar observations with NuSTAR as we go through the current solar minimum.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSH41F3335H
- Keywords:
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- 7599 General or miscellaneous;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7899 General or miscellaneous;
- SPACE PLASMA PHYSICS;
- 7999 General or miscellaneous;
- SPACE WEATHER