A Catalog of GALEX Ultraviolet Emission from Asymptotic Giant Branch Stars

Abstract

We have performed a comprehensive study of the UV emission detected from AGB stars by the Galaxy Evolution Explorer (GALEX). Of the 468 AGB stars in our sample, 316 were observed by GALEX. In the NUV bandpass (${\lambda }_{\mathrm{eff}}\sim 2310$z A), 179 AGB stars were detected and 137 were not detected. Only 38 AGB stars were detected in the FUV bandpass (${\lambda }_{\mathrm{eff}}\sim 1528$ A). We find that NUV emission is correlated with optical to near infrared emission leading to higher detection fractions among the brightest, hence closest, AGB stars. Comparing the AGB time-variable visible phased light curves to corresponding GALEX NUV phased light curves we find evidence that for some AGB stars the NUV emission varies in phase with the visible light curves. We also find evidence that the NUV emission, and possibly, the FUV emission are anti-correlated with the circumstellar envelope density. These results suggest that the origin of the GALEX-detected UV emission is an inherent characteristic of the AGB stars that can most likely be traced to a combination of photospheric and chromospheric emission. In most cases, UV detections of AGB stars are not likely to be indicative of the presence of binary companions.

Accepted by ApJ; go spurs go!

References in corpus (7)

• New Grids of ATLAS9 Model Atmospheres
• Near-Infrared Photometry of Carbon Stars
• Mass-loss properties of S-stars on the AGB
• Ultraviolet emission from main-sequence companions of AGB stars
• Detection of `parent' molecules from the inner wind of AGB stars as tracers of non-equilibrium chemistry
• HST Observations of Chromospheres in Metal Deficient Field Giants
• Determination of pulsation periods and other parameters of 2875 stars classified as MIRA in the All Sky Automated Survey (ASAS)

Cited by in corpus (6)

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• Photodissociation of CO in the outflow of evolved stars
• The Role of Internal Photons on the Chemistry of the Circumstellar Envelopes of AGB Stars
• HD101584: Circumstellar characteristics and evolutionary status
• A Correction for GALEX Spectroscopic UV Flux Distributions from Comparisons with CALSPEC and IUE