Starspot Areas and Temperatures on Active Stars from TiO Bands

Session 45 -- Stellar Activity I
Display presentation, Tuesday, 10, 1995, 9:20am - 6:30pm

[45.07] Starspot Areas and Temperatures on Active Stars from TiO Bands

Douglas O'Neal and James E. Neff (Penn State), Steven H. Saar (Harvard-Smithsonian Center for Astrophysics)

We present results from a study of starspot areas and temperatures on active stars using the 7055\AA\ and 8860\AA\ absorption bands of the titanium oxide (TiO) molecule. These two bands have different temperature sensitivities, so the ratio of their strengths in a spotted star spectrum constrains the spot temperature, while the absolute strengths are a function of total starspot area. This spectroscopic technique complements Doppler Imaging and light-curve modeling studies because it can measure spot distributions on even uniformly-spotted or slowly-rotating stars. We present results for four active giant or subgiant stars: EI Eridani, V1794 Cygni, Sigma Geminorum, and V1762 Cygni. In multiple epochs of observation, the spot coverages we detected on those stars ranged from below our sensitivity level to approximately 35\%.

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