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The He-shell flash in action: T Ursae Minoris revisited

K. Szatmary·L. L. Kiss·Zs. Bebesi
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Abstract

We present an updated and improved description of the light curve behaviour of T Ursae Minoris, which is a Mira star with the strongest period change (the present rate is an amazing -3.8+/-0.4 days/year corresponding to a relative decrease of about 1% per cycle). Ninety years of visual data were collected from all available databases and the resulting, almost uninterrupted light curve was analysed with the O-C diagram, Fourier analysis and various time-frequency methods. The Choi-Williams and Zhao-Atlas-Marks distributions gave the clearest image of frequency and light curve shape variations. A decrease of the intensity average of the light curve was also found, which is in accordance with a period-luminosity relation for Mira stars. We predict the star will finish its period decrease in the meaningfully near future (c.c. 5 to 30 years) and strongly suggest to closely follow the star's variations (photometric, as well as spectroscopic) during this period.

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K. Szatmary, L. L. Kiss, Zs. Bebesi. 2002-11-13. The He-shell flash in action: T Ursae Minoris revisited. https://doi.org/10.1051/0004-6361%3A20021646

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