Observations from the HRTS-9 Rocket in the NUV Passband of the IRIS Mission
Abstract
The HRTS-9 rocket flew in April 1995 and observed a variety of solar surface features on the western portion of the solar disk. Unlike previous flights, the spectrograph was modified to observe a roughly 180 A wide portion the NUV solar spectrum near the Mg II doublet at 2800 A. In addition, a slit-jaw camera observed a 400 x 900 arcsecond region around the 960 arcsecond long (1 Rsun) x 1 arcsecond wide spectrograph slit in four UV passbands. Specifically, a series of narrowband images were measured at 1540 A (Si I), 1550 A ( C IV), 1560 A ( C I), and 1600 A (continuum). Images of H-alpha were measured as well. During the flight, the spectrograph slit was pointed at various features including the quiet sun near disk center and the limb, several active regions, and a sunspot. During the final portion of the flight, the rocket pointing was fixed and a slit scanning mechanism was used to collect a series of spectra that span about 45 arcseconds. From this data set spectral images at specific wavelengths in the 2765 to 2885 A range can be generated and compared to the broadband images at shorter wavelengths. For example, preliminary spectral images in the Mg II k line show evidence of loop structures similar to those seen in C IV. Our previous efforts with this data set has focused on the impact these radiance observations near Mg II have on solar spectral irradiance studies. These topics include examining the sources of solar irradiance variability, the center-to-limb variability of the quiet sun, and the relationship between the Mg II intensity and the photospheric magnetic field. In light of the upcomming IRIS Explorer mission, we are turning our attention to those science goals in order to anticipate and support potential observations by the IRIS NUV spectrograph channel. In this presentation we will present an overview of the available observations and previous results as well as discuss our ongoing analysis and preliminary spectral images of features in the region near Mg II.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFMSH13B1961K
- Keywords:
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- 7507 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY / Chromosphere;
- 7529 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY / Photosphere;
- 7538 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY / Solar irradiance;
- 7549 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY / Ultraviolet emissions