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FUV emission from AGB stars: modeling accretion activity associated with a binary companion

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dc.contributor.advisor Sahai, Raghvendra en_US Stevens, Alyx Catherine 2013-06-21T15:33:11Z 2013-06-21T15:33:11Z 2012-12-21
dc.identifier.citation NASA Undergraduate Student Research Program (USRP), Pasadena, California, December 21, 2012 en_US
dc.identifier.clearanceno 12-5991
dc.description.abstract It is widely believed that the late stages of evolution for Asymptotic Giant Branch (AGB) stars are influenced by the presence of binary companions. Unfortunately, there is a lack of direct observational evidence of binarity. However, more recently, strong indirect evidence comes from the discovery of UV emission in a subsample of these objects (fuvAGB stars). AGB stars are comparatively cool objects (≤ 3000 K), thus their fluxes falls off drastically for wavelengths 3000A and shorter. Therefore, ultraviolet observations offer an important, new technique for detecting the binary companions and/or associated accretion activity. We develop new models of UV emission from fuvAGB stars constrained by GALEX photometry and spectroscopy of these objects. We compare the GALEX UV grism spectra of the AGB M7 star EY Hya to predictions using the spectral synthesis code Cloudy, specifically investigating the ultraviolet wavelength range (1344-2831Å). We investigate models composed of contributions from a photoionized "hot spot" due to accretion activity around the companion, and "chromospheric" emission from collisionally ionized plasma, to fit the UV observations. en_US
dc.description.sponsorship NASA/JPL en_US
dc.language.iso en_US en_US
dc.publisher Pasadena, CA : Jet Propulsion Laboratory, National Aeronautics and Space Administration, 2012. en_US
dc.subject ultraviolet emission en_US
dc.subject binarity en_US
dc.subject Asymptotic Giant Branch (AGB) stars en_US
dc.subject accretion en_US
dc.subject mass-loss en_US
dc.title FUV emission from AGB stars: modeling accretion activity associated with a binary companion en_US
dc.type Student Report en_US
dc.subject.NASATaxonomy Astrophysics en_US

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