Solar coronal lines in the visible and infrared. A rough guide

Abstract

We review the coronal visible and infrared lines, collecting previous observations, and comparing, whenever available, observed radiances with those predicted by various models: the quiet Sun, a moderately active Sun, and an active region as observed near the limb, around 1.1R${}_{\odot }$. We also model the off-limb radiances for the quiet Sun case. We used the most up-to-date atomic data in CHIANTI version 8. The comparison is satisfactory, in that all of the strong visible lines now have a firm identification. We revise several previous identifications and suggest some new ones. We also list the large number of observed lines for which we do not currently have atomic data, and therefore still await firm identifications. We also show that a significant number of coronal lines should be observable in the near-infrared region of the spectrum by the upcoming Daniel K. Inouye Solar Telescope (DKIST) and the AIR-Spec instrument, which observed the corona during the 2017 August 21 solar eclipse. We also briefly discuss the many potential spectroscopic diagnostics available to the visible and infrared, with particular emphasis on measurements of electron densities and chemical abundances. We briefly point out some of the potential diagnostics that could be available with the future infrared instrumentation that is being built for DKIST and planned for the Coronal Solar Magnetism Observatory (COSMO). Finally, we highlight the need for further improvements in the atomic data.

arXiv commentSubmitted to ApJ - revised

References in corpus (13)

• The chemical composition of the Sun
• CHIANTI - An atomic database for Emission Lines. Version 8
• The FIP and Inverse FIP Effects in Solar and Stellar Coronae
• CHIANTI - an Atomic Database for Emission Lines. Paper VI: Proton Rates and Other Improvements
• Observations of Active Region Loops with the EUV Imaging Spectrometer on Hinode
• The Effect of Proton Temperature Anisotropy on the Solar Minimum Corona and Wind
• The Temperature Dependence of Solar Active Region Outflows
• The Temperature and Density Structure of the Solar Corona. I. Observations of the Quiet Sun with the EUV Imaging Spectrometer (EIS) on Hinode
• Benchmarking atomic data for astrophysics: a first look at the soft X-ray lines
• Signatures of the non-Maxwellian $\kappa$-distributions in optically thin line spectra \subtitle{I. Theory and synthetic Fe IX--XIII spectra}
• From Forbidden Coronal Lines to Meaningful Coronal Magnetic Fields
• Imaging and Spectroscopic Observations of a Transient Coronal Loop: Evidence for the Non-Maxwellian $\kappa$-Distributions
• Coronal Diagnostics from Narrowband Images around 30.4 nm

Cited by in corpus (30)

• Solar UV and X-Ray Spectral Diagnostics
• Global maps of the magnetic field in the solar corona
• Critical Science Plan for the Daniel K. Inouye Solar Telescope (DKIST)
• The European Solar Telescope
• Defining the Middle Corona
• Investigating `dark' energy in the solar corona using forward modeling of MHD waves
• Mapping the Sun's coronal magnetic field using the Zeeman effect
• Identifying the Coronal Source Regions of Solar Wind Streams from Total Solar Eclipse Observations and in situ Measurements Extending Over a Solar Cycle
• The EUV spectrum of the Sun: quiet and active Sun irradiances and chemical composition
• The Solar Minimum Eclipse of 2019 July 2: II. The First Absolute Brightness Measurements and MHD Model Predictions of Fe X, XI and XIV out to 3.4 Rs
• The Effect of Solar Wind Expansion and Non-Equilibrium Ionization on the Broadening of Coronal Emission Lines
• Helium line emissivities in the solar corona
• Using multi-line spectropolarimetric observations of forbidden emission lines to measure single-point coronal magnetic fields
• Predicting the COSIE-C Signal from the Outer Corona up to 3 Solar Radii
• Hinode EIS line widths in the quiet corona up to 1.5 Rsun
• Coronal Plasma Characterization via Coordinated Infrared and Extreme Ultraviolet Observations of a Total Solar Eclipse
• New deep coronal spectra from the 2017 total solar eclipse
• R-matrix electron-impact excitation data for the C-like iso-electronic sequence
• Fantastic Fits with fantasy of Active Galactic Nuclei Spectra -- Exploring the Fe II emission near the H$\alpha$ line
• Coronal Densities, Temperatures and Abundances During the 2019 Total Solar Eclipse: The Role of Multi-Wavelength Observations in Coronal Plasma Characterization
• Observation of Electric Octupole Emission Lines Strongly Enhanced by an Anomalous Behavior of Cascading Contribution
• Elemental composition in quiescent prominences
• Electron Densities in the Solar Corona Measured Simultaneously in the Extreme-Ultraviolet and Infra-Red
• New Observations of the IR Emission Corona from the July 2, 2019 Eclipse Flight of the Airborne Infrared Spectrometer
• Spectrally resolved imaging with the solar gravitational lens
• The Airborne Infrared Spectrometer: Development, Characterization, and the 21 August 2017 Eclipse Observation
• Extended Calculations with Spectroscopic Accuracy: Energy Levels and Radiative Rates for O-like Ions between Ar XI and Cr XVII
• Reduced atomic models for large-scale computations: Fe XIII near-infrared lines
• A spectroscopic survey of infrared 1-4μm spectra in regions of prominent solar coronal emission lines of Fe XIII, Si X, and Si IX
• R-matrix electron-impact excitation data for the O-like iso-electronic sequence