Loading...
Please wait, while we are loading the content...
Similar Documents
A search for evolutionary changes in planetary nuclei: a continuation
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Altner, Bruce |
| Copyright Year | 1995 |
| Description | This report summarizes the final results of an IUE investigation to search for signs of evolutionary changes in high-mass central stars of planetary nuclei, as evidenced by UV-optical fading over the lifetime of the satellite. The program is a continuation of an earlier investigation, expanding the target list to include more types of hot central stars and to obtain more spectra of previously observed stars. In order to compare the IUE fluxes of a central star obtained over a more-than-ten-year timespan, several steps were necessary, including reprocessing of very early spectra and correction for the sensitivity degradation of the SWP camera over time. The results indicate that while a few stars appear to have diminished UV fluxes compared to earlier IUE observations, the evidence for this is less than overwhelming due to the sparseness of the data. Those stars which emerge from this study as viable candidates for having faded are the cooler Of-type stars (O6f-O7f), i.e., those for which the change in spectral energy with increasing temperature is greatest. The report describes the data analysis steps and discusses the uncertainties in both the data and in the resulting fading rates. Estimates of stellar mass based on theoretical evolutionary rates are also provided. |
| File Size | 3567061 |
| Page Count | 81 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19960002337 |
| Archival Resource Key | ark:/13960/t5fc00h73 |
| Language | English |
| Publisher Date | 1995-09-23 |
| Access Restriction | Open |
| Subject Keyword | Astrophysics Stellar Spectra Fading Hot Stars Stellar Mass Planetary Evolution Ultraviolet Spectra Iue Stellar Evolution Planetary Nebulae Ultraviolet Astronomy Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
