Loading...
Please wait, while we are loading the content...
Similar Documents
Carbon stars with oxygen-rich circumstellar material
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Hawkins, I. Jura, Michael |
| Copyright Year | 1991 |
| Description | The IUE satellite was used to search for companions to two carbon-rich stars with oxygen-rich circumstellar envelopes, EU And and V778 Cyg. Depending upon the amount of interstellar extinction and distances (probably between 1 and 2 kpc from the Sun) to these two stars, upper limits were placed between approx. 1.5 and 6 solar mass to the mass of any main sequence companions. For the 'near' distance of 1 kpc, it seems unlikely that there are white dwarf companions because the detection would be expected of ultraviolet emission from accretion of red giant wind material onto the white dwarf. A new model is proposed to explain the oxygen-rich envelopes. If these stars have a high nitrogen abundance, the carbon that is in excess of the oxygen may be carried in the circumstellar envelopes in HCN rather than C2H2 which is a likely key seed molecule for the formation of carbon grains. Consequently, carbon particles may not form; instead, oxygen-rich silicate dust may nucleate from the SiO present in the outflow. |
| File Size | 761793 |
| Page Count | 25 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19920011972 |
| Archival Resource Key | ark:/13960/t4dn92406 |
| Language | English |
| Publisher Date | 1991-01-16 |
| Access Restriction | Open |
| Subject Keyword | Astrophysics Stellar Spectra Red Giant Stars Oxygen Ultraviolet Spectra Main Sequence Stars Nitrogen Carbon Stars Carbon Stellar Envelopes Hydrocyanic Acid Cosmic Dust Stellar Mass Interstellar Extinction Iue Ultraviolet Emission 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 |
