edu.ucar.opensky::articles:15247 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T16:24:47.248943 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7gt5p55 Lines of OIV and SIV in the Goddard High-Resolution Spectrograph spectrum of RR Tel: Constraints on atomic data 1999-03-01T00:00:00Z publication https://n2t.org/ark:/85065/d7gt5p55 https://doi.org/10.1046/j.1365-8711.1999.02392.x Harper, G. author Jordan, C. author Judge, Philip G. author Robinson, R. author Carpenter, K. author Brage, T. author UCAR/NCAR - Library publisher High signal-to-noise ratio spectra of RR Tel obtained at medium resolution with the Goddard High-Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST) are used to test available atomic data for the OIV 2s²2p²P--2s2p²⁴P multiplet (UV 0.01). The fine-structure intervals of the 2s2p²⁴P term given by Moore (1983) appear to need revision. The flux ratios of lines within multiplet UV (0.01), which have a common upper level, depend only on transition probabilities. The observed flux ratio of lines from the ⁴P3/2' level differs from that predicted by theory, but this difference cannot be attributed to a blend with a line of SIV]. At the electron densities in the RR Tel nebula, other flux ratios give information on the relative electron excitation rates between the ²P and ⁴ fine-structure levels. Using the collision strengths calculated by Zhang, Graziani & Pradhan, the rate to the ⁴P5/2' level, relative to the rates to the other J states, appears to be underestimated by ~ 10 per cent, which is within the expected uncertainty of 20 per cent. We also discuss the SIV 3s²3p ²P--3s3p²⁴P multiplet. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 1999 Royal Astronomical Society. The definitive version is available at http://onlinelibrary.wiley.com. None eng geoscientificInformation