New Observations of the IR Emission Corona from the July 2, 2019 Eclipse Flight of the Airborne Infrared Spectrometer

Abstract

The Airborne Infrared Spectrometer (AIR-Spec) was commissioned during the 2017 total solar eclipse, when it observed five infrared coronal emission lines from a Gulfstream V (GV) research jet owned by the National Science Foundation (NSF) and operated by the National Center for Atmospheric Research (NCAR). The second AIR-Spec research flight took place during the July 2, 2019 total solar eclipse across the South Pacific. The 2019 eclipse flight resulted in seven minutes of observations, during which the instrument measured all four of its target emission lines: S XI 1.393 $\mu$m, Si X 1.431 $\mu$m, S XI 1.921 $\mu$m, and Fe IX 2.853 $\mu$m. The 1.393 $\mu$m line was detected for the first time, and probable first detections were made of Si XI 1.934 $\mu$m and Fe X 1.947 $\mu$m. The 2017 AIR-Spec detection of Fe IX was confirmed and the first observations were made of the Fe IX line intensity as a function of solar radius. Telluric absorption features were used to calibrate the wavelength mapping, instrumental broadening, and throughput of the instrument. AIR-Spec underwent significant upgrades in preparation for the 2019 eclipse observation. The thermal background was reduced by a factor of 30, providing a 5.5x improvement in signal-to-noise ratio, and the post-processed pointing stability was improved by a factor of five to $<$10 arcsec rms. In addition, two imaging artifacts were identified and resolved, improving the spectral resolution and making the 2019 data easier to interpret.

19 pages, 16 figures, 5 tables

References in corpus (6)

• Solar coronal lines in the visible and infrared. A rough guide
• Coronal Magnetic Field Topology From Total Solar Eclipse Observations
• Identifying the Coronal Source Regions of Solar Wind Streams from Total Solar Eclipse Observations and in situ Measurements Extending Over a Solar Cycle
• CME Induced Thermodynamic Changes in the Corona as Inferred from Fe XI and Fe XIV Emission Observations during the 2017 August 21 Total Solar Eclipse
• The Airborne Infrared Spectrometer: Development, Characterization, and the 21 August 2017 Eclipse Observation
• A new facility for airborne solar astronomy: NASA's WB-57 at the 2017 total solar eclipse

Cited by in corpus (3)

• Coronal Densities, Temperatures and Abundances During the 2019 Total Solar Eclipse: The Role of Multi-Wavelength Observations in Coronal Plasma Characterization
• The Solar Minimum Eclipse of 2019 July 2. III. Inferring the Coronal $T_e$ with a Radiative Differential Emission Measure Inversion
• The Airborne Infrared Spectrometer: Development, Characterization, and the 21 August 2017 Eclipse Observation