A Search for Mass Loss from Metal-Poor Field Red Giants using Data from the WISE and AKARI Satellites

作者：Smith Graeme H^*; Bashay Edward A

来源：Publications of the Astronomical Society of the Pacific, 2014, 126(941): 605-615.

All-sky photometry from the WISE and AKARI satellite observatories has been used to obtain mid-infrared photometry in the 4-20 mu m range for a sample of almost 400 red giants with metallicities of [Fe/H] <= -0.6. The mid-infrared photometry has been combined with J and K-S 2MASS photometry to produce a series of two-color diagrams from which stars having circumstellar dust can be identified, namely (K-S - W3, K-S - W4) and (W1 - W3, W1 - W4) derived from WISE data and an analogous (K-S - S9W, K-S - L18W) diagram based on AKARI photometry. All three diagrams exhibit sequences of giants that are candidates for having circumstellar dust. Of the 8 metal-poor giants with the greatest mid-infrared excesses all but one are known to be in advanced stages of evolution, and are typically pulsating variables. Among giants with more modest evidence of emission in the WISE W3 bandpass, i.e., stars with 0.2 < (K-S - W3) <0.5 or (W1 - W3) > 0.10, there are also a number of known variables, but the SIMBAD data base does not list all such stars as variables. Photometric monitoring of this sample of mild-infrared-excess giants could help elucidate the potential connection between dust formation and stellar pulsation.

• 出版日期2014-7