GIANT CONVECTION CELL TURNOVER AS AN EXPLANATION OF THE LONG SECONDARY PERIODS IN SEMIREGULAR RED VARIABLE STARS

被引:55
作者
Stothers, Richard B. [1 ]
机构
[1] NASA, Goddard Inst Space Studies, New York, NY 10025 USA
关键词
convection; stars: interiors; stars: late-type; stars: oscillations; stars: variables: general; SOLAR-LIKE OSCILLATIONS; MIXING-LENGTH; ALPHA-ORIONIS; EFFECTIVE TEMPERATURES; VELOCITY VARIATIONS; RADIAL-VELOCITY; MASS-LOSS; PULSATION; STELLAR; SUPERGIANTS;
D O I
10.1088/0004-637X/725/1/1170
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Giant convection cells in the envelopes of massive red supergiants turn over in a time comparable in order of magnitude with the observed long secondary periods in these stars, according to a theory proposed some years ago by Stothers & Leung. This idea is developed further here by using improved theoretical data, especially a more accurate convective mixing length and a simple calculation of the expected radial-velocity variations at the stellar surface. The theory is applied to the two best-observed red supergiants, Betelgeuse and Antares, with more success than in the earlier study. The theory can also explain the long secondary periods seen in the low-mass red giants, thus providing a uniform and coherent picture for all of the semiregular red variables. How the turnover of a giant convection cell might account for the observed slow light and radial-velocity variations, their relative phasing, and the absence of these variations in certain stars is discussed here in a qualitative way, but follows naturally from the theory.
引用
收藏
页码:1170 / 1174
页数:5
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