The optical spectrum of Eta Carinae (η Car) is prominent in H I, He i and Fe ii wind lines, all of which vary both in absorption and emission with phase. The phase dependance is a consequence of the interaction between the two objects in the η Car binary (η Car A & B). The binary system is enshrouded by ejecta from previous mass ejection events and consequently, η Car B is not directly observable. We have traced the He i lines over η Car’s spectroscopic period, using HST/STIS data obtained with medium spectral, but high angular, resolving power, and created a radial velocity curve for the system. The He I lines are formed in the core of the system, and appear to be a composite of multiple features formed in spatially separated regions. The sources of their irregular line profiles are still not fully understood, but can be attributed to emission/absorption near the wind-wind interface and/or a direct consequence of the η Car A’s, massive, clumpy wind.
This paper will discuss the spectral variability, the narrow emission structure of the He i lines and how clumpiness of the winds may impede the construction of the reliable radial velocity curve, necessary for characterizations of especially η Car B.
| Identifer | oai:union.ndltd.org:Potsdam/oai:kobv.de-opus-ubp:1822 |
| Date | January 2007 |
| Creators | Nielsen, K. E. |
| Publisher | Universität Potsdam, Extern. Extern |
| Source Sets | Potsdam University |
| Language | English |
| Detected Language | English |
| Type | InProceedings |
| Format | application/pdf |
| Rights | http://opus.kobv.de/ubp/doku/urheberrecht.php |
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