RAT J0455+1305: a rare hybrid pulsating subdwarf B star

We present results on the second faintest pulsating subdwarf B (sdB) star, RAT J0455+1305, derived from photometric data obtained in 2009. It shows both short- and long-period oscillations, theoretically assigned as pressure and gravity modes. We identify six short-period frequencies (with one being a combination) and six long-period frequencies. This star is the fourth hybrid sdB star discovered so far which makes it of special interest as each type of mode probes a different part of the star. This star is similar to the sdB hybrid pulsator Balloon 090100001 in that it exhibits short-period mode groupings, which can be used to identify pulsation parameters and constrain theoretical models.