Loading...
Please wait, while we are loading the content...
Similar Documents
First detection of krypton and xenon in a white dwarf
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Rauch Sr., Thomas Kruk, Jeffrey W. Werner Sr., Klaus Ringat, Ellen |
| Copyright Year | 2012 |
| Description | We report on the first detection of the noble gases krypton (Z = 36) and xenon (54) in a white dwarf. About 20 KrVI-VII and Xe VI-VII lines were discovered in the ultraviolet spectrum of the hot DO-type white dwarf RE 0503-289. The observations, performed with the Far Ultraviolet Spectroscopic Explorer, also reveal highly ionized photospheric lines from other trans-iron group elements, namely Ga (31), Ge (32), As (33), Se (34), Mo (42), Sn (50), Te (52), and I (53), from which gallium and molybdenum are new discoveries in white dwarfs, too. For Kr and Xe, we performed an NLTE analysis and derived mass fractions of log Kr = -4.3 plus or minus 0.5 and log Xe = -4.2 plus or minus 0.6, corresponding to an enrichment by factors of 450 and 3800, respectively, relative to the Sun. The origin of the large overabundances is unclear. We discuss the roles of neutron-capture nucleosynthesis in the-precursor star and radiation-driven diffusion. It is possible that diffusion is insignificant and thaI the observed metal abundances constrain the evolutionary history of the star. Its hydrogen deficiency may be the consequence of a late helium-shell nash or a binary white dwarf merger. |
| File Size | 2201358 |
| Page Count | 6 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20120017019 |
| Archival Resource Key | ark:/13960/t1bk6c76w |
| Language | English |
| Publisher Date | 2012-06-08 |
| Access Restriction | Open |
| Subject Keyword | Astronomy Astrophysics White Dwarf Stars Energy Spectra Xenon Neutrons Abundance Far Uv Spectroscopic Explorer Krypton Detection Sun Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
