STELLA and Amadeus – the case of XX Trianguli
XX Tri is monitored by STELLA and Amadeus APT from the beginning of their
operation time of 10 and 20 years, respectively. Already in 1998
simultaneous photometry and spectroscopy revealed serious problems
concerning the temperature distribution on the stellar surface. During the
last three decades XX Tri has shown more than 1 magnitude overall change,
and its explanation is far from satisfactory. However, using together
STELLA SES spectra and Amadeus photometry obtained during the last 10
years, we could be able to shed at least some light to the nature of the
huge brightness and spottedness change of this notorious star. The talk
will raise up possibilities to do so.