TYC 3637-1152-1 - A high amplitude δ Scuti star with peculiar pulsational properties
Meingast, Stefan; Sulzenauer, Nikolaus; Pribulla, Theodor; Paunzen, Ernst; Hümmerich, Stefan; Bernhard, Klaus; Komžík, Richard; Janík, Jan; Frauenberger, Moriz; Helbig, Santiago; Herdin, Andreas; Karnthaler, Andreas; Kulterer, Beatrice; Maitzen, Hans-Michael; Miksch, Sebastian; Rode-Paunzen, Monika; Sakuler, Wolfgang; Schoder, Carla; Semenko, Eugene
Czech Republic, Germany, United States, Austria, Slovakia, Russia
Abstract
In some δ Scuti stars, only one or two radial modes are excited (usually the fundamental mode and/or first overtone mode) and the observed peak-to-peak amplitudes exceed 0.3 mag (V). These stars are known as High Amplitude Delta Scuti (HADS) variables.
We here present a detailed photometric and spectroscopic analysis of the HADS star TYC 3637-1152-1. We have derived a metallicity close to solar, a spectral type of F4 V and an age of logt = 9.1 . Employing archival time series data from different sources, two frequencies f0 = 10.034 c/d and f1 = 12.681 c/d and their harmonics and linear combinations were identified. The period ratio of f0 /f1 = 0.791 puts this star into a peculiar position in the Petersen diagram, from which we conclude that TYC 3637-1152-1 is a unique object with peculiar pulsational properties that indicate a transitional state between HADS stars pulsating in the fundamental and first overtone modes and stars pulsating in higher overtones.