The HST Treasury Project on Eta Carinae
Abstract
This program is valuable for a broad range of stellar and nebular astrophysics, as well as data processing techniques and instrument characteristics. While observing this object's mysterious 5.5-year cycle, we obtained data on several distinct, complex, unfamiliar classes of spectra which cannot be observed well elsewhere. The stellar wind parameters lie outside normal experience, the Weigelt ejecta produce narrow-line spectra unlike any other known object, and the other spectra are also unusual. Altogether our results pertain to stellar instabilities close to the Eddington limit, extreme stellar winds, unexplored nebular/atomic excitation processes, nebular gas dynamics, and instrument performance.
The project also represents an extreme application of HST spectroscopy. Since η Car and its ejecta are spatially, spectrally, and temporally complex, they require the best available performance of HST/STIS across its full wavelength range. Such observations will probably not be attainable again within the next 15 years. They also require improved data processing techniques which we have developed, useful for HST/STIS programs on other objects. The Eta Car Treasury data archive will be pertinent to a variety of significant problems mentioned above -- not just η Carinae. (See a related poster concerning the Archive.) Here we report that (1) the predicted event did indeed occur during May--July 2003; (2) we obtained the planned data; (3) they show numerous fascinating and difficult-to-explain phenomena; and (4) we sketch improved reduction routines to achieve maximum resolution with STIS/CCD data in general. We also show examples of the spectral structure and variations in Eta Carinae. This project is supported by STScI grant GO-9420.- Publication:
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American Astronomical Society Meeting Abstracts
- Pub Date:
- December 2003
- Bibcode:
- 2003AAS...203.5805D