2016/07/28 by T. R. Gull, Theodore R. Gull, Thomas Madura +21 · 2 citations
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Atmospheric sciences #Ion #Ionization #Optics #Physics #Primary (astronomy) #Radiative transfer #Stellar, planetary, and galactic studies #Trace gas #astro-ph.SR
paper · pdf · doi:10.1093/mnras/stw1829
28 pages accepted MNRAS July 22 2016
openalex publication_date 2016/07/28 · arxiv created 2016/08/22 · openalex created_date 2016/08/23 · arxiv updated 2016/09/07 · openalex updated_date 2026/08/05
Eta Carinae, the closest, active, massive binary containing a highly unstable Luminous Blue Variable, exhibits expanding, compressed wind shells, seen in emission, that are spatially and spectrally resolved by Hubble Space Telescope/Space Telescope Imaging Spectrograph. Starting in 2009 June, these structures were mapped across its 5.54-yr, highly elliptical, binary orbit to follow temporal changes in the light of [Fe iii] 4659 Å and [Fe ii] 4815 Å. The emissions trace portions of fossil wind shells, that were formed by wind–wind interactions across each cycle. Over the high-ionization state, dense arcs, photoionized by far-ultraviolet radiation from the hot secondary, are seen in [Fe iii]. Other arcs, ionized by mid-ultraviolet radiation from the primary star, are seen in [Fe ii]. The [Fe iii] structures tend to be interior to [Fe ii] structures that trace extensive, less disturbed primary wind. During the brief periastron passage when the secondary plunges deep into the primary's extremely dense wind, on the far side of primary star, high-ionization [Fe iii] structures fade and reappear in [Fe ii]. Multiple fossil wind structures were traced across the 5.7-yr monitoring interval. The strong similarity of the expanding [Fe ii] shells suggests that the wind and photoionization properties of the massive binary have not changed substantially from one orbit to the next over the past several orbital cycles. These observations trace structures that can be used to test 3D hydrodynamical and radiative-transfer models of massive, interacting winds. They also provide a baseline for following future changes in η Car, especially of its winds and photoionization properties.