Publication Abstracts

Chiu et al. 1977

Chiu, H.Y., P.J. Adams, J.L. Linsky, G.S. Basri, S.P. Maran, and R.W. Hobbs, 1977: High-resolution stellar vidicon spectrophotometry. I. Variable mass loss from Arcturus and the hypothesis of giant convective elements. Astrophys. J., 211, 453-462, doi:10.1086/154951.

High-resolution spectrophotometry of the variable Ca II K-line in the K2 IIIp star α Boo was performed on five occasions over the period 1974 April-1976 February with the McMath Solar Telescope at Kitt Peak National Observatory and an experimental SEC vidicon camera. The results are compared with Copernicus observations of the Mg II hand k lines (1973 May 19; 1974 May 20) and with earlier Ca II data of Griffin, and it is found that either of two states may typically occur in the Arcturus chromosphere. From comparison with the results of model calculations for expanding chromospheres, it is concluded that these correspond respectively to a "normal" state in which the mass loss dM/dt < 10-9 M/yr and an "abnormal" state in which dM/dt — 8×10-9 M/yr. In the latter case, the expansion velocity is ∼13 km/s at optical depth unity in the K-line, which exceeds the local sound speed. It is suggested that the abnormal state represents the rise to the photosphere of a very large convective element (d ∼ r*) as hypothesized for red giants by Schwarzschild.

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BibTeX Citation

@article{ch01900k,
  author={Chiu, H. Y. and Adams, P. J. and Linsky, J. L. and Basri, G. S. and Maran, S. P. and Hobbs, R. W.},
  title={High-resolution stellar vidicon spectrophotometry. I. Variable mass loss from Arcturus and the hypothesis of giant convective elements},
  year={1977},
  journal={Astrophysical Journal},
  volume={211},
  pages={453--462},
  doi={10.1086/154951},
}

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RIS Citation

TY  - JOUR
ID  - ch01900k
AU  - Chiu, H. Y.
AU  - Adams, P. J.
AU  - Linsky, J. L.
AU  - Basri, G. S.
AU  - Maran, S. P.
AU  - Hobbs, R. W.
PY  - 1977
TI  - High-resolution stellar vidicon spectrophotometry. I. Variable mass loss from Arcturus and the hypothesis of giant convective elements
JA  - Astrophys. J.
JO  - Astrophysical Journal
VL  - 211
SP  - 453
EP  - 462
DO  - 10.1086/154951
ER  -

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