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| Paper: |
The UV Spectra of Mira Variables: A View with HST |
| Volume: |
154, Cool Stars, Stellar Systems and the Sun: Tenth Cambridge Workshop |
| Page: |
1613 |
| Authors: |
Luttermoser, Donald G.; Mahar, Susan |
| Abstract: |
We report on the first set of UV spectra taken of Mira stars under high dispersion with the Goddard High Resolution Spectrograph onboard the Hubble Space Telescope. Two spectral regions were observed, 2320 AA - 368 AA to record the C 2] (UV0.01) multiplet and 2785 AA - 2835 AA to obtain the Mg 2 h & k lines, for the Mira variable stars R Hya (phase 0.26) and R Leo (phase 0.12). The R Hya Mg 2 spectrum is very clean and shows overlying absorption from Fe 1 (UV3) and Mn 1 (UV1) over the k line. The fluoresced Fe 1 (UV44) feature at 2824 \AA is plainly visible in this spectrum, whereas past {\em IUE} observations at high dispersion were unable to record this feature. Remarkably, the newly identified fluoresced Fe 1 (UV45) feature near 2807 \AA is seen in this spectrum. Until now, this line has only been seen in cool carbon stars with {\em HST}/HRS. It is remarkable in that it is pumped by the thin C 2] (UV0.01) emission line at 2325.5 \AA in the carbon stars. This line is the likely pump in the oxygen-rich Miras in our sample as well. Two of the strongest C 2] (UV0.01) near 2325 \AA are plainly seen in our spectrum. This region of the spectrum, however, is dominated by the Si 2] (UV0.01) line near 2335 AA, opposite to what is observed in the carbon stars and the non-Mira oxygen-rich red giant stars. Very weak Mg 2 lines are seen in the R Leo spectrum at phase 0.12. At this phase, these lines are typically absent in IUE spectra. |
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